Ideas from 'Critique of Pure Reason' by Immanuel Kant [1781], by Theme Structure

[found in 'Critique of Pure Reason' by Kant,Immanuel (ed/tr Guyer,P /Wood,A W) [CUO 1998,0-521-65729-6]].

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1. Philosophy / A. Wisdom / 1. Nature of Wisdom
Cleverness is shown in knowing what can reasonably be asked
                        Full Idea: It is already a great and necessary proof of cleverness or insight to know what one should reasonably ask.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B082/A58)
                        A reaction: I admire the asking of unreasonable questions. They stretch the imagination, and the fixing of the limits of human thought requires some attempt to go beyond the limit. Kant sounds wise but conservative.
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / e. Philosophy as reason
Reason is only interested in knowledge, actions and hopes
                        Full Idea: All interest of my reason (the speculative as well as the practical) is united in the following three questions: 1) What can I know?, 2) What should I do?, and 3) What may I hope?
                        From: Immanuel Kant (Critique of Pure Reason [1781], B833/A805)
                        A reaction: Maybe reason is also interested in itself. And presumably it doesn't lose interest in what is clearly unknowable, or unachievable, or beyond all hope?
1. Philosophy / D. Nature of Philosophy / 7. Despair over Philosophy
In ordinary life the highest philosophy is no better than common understanding
                        Full Idea: In regard to the essential ends of human nature even the highest philosophy cannot advance further than the guidance that nature has also conferred on the most common understanding.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B859/A831)
                        A reaction: This is a very anti-elitist remark which seems to me to reflect Kant's Christian background. It seems obvious to me that in politics our best leaders are not confined to 'common understanding'. Nor in morality. Moral saints are wiser.
1. Philosophy / E. Nature of Metaphysics / 1. Nature of Metaphysics
Metaphysics is a systematic account of everything that can be known a priori
                        Full Idea: Metaphysics can be ...the investigation of everything that can ever be cognized a priori, as well as the presentation of that which constitutues a system of pure philosophical cognitions of this kind.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B869/A841)
                        A reaction: [He excludes mathematics from this] Moore says this is Kant's most interesting definition of metaphysics (among several versions).
1. Philosophy / E. Nature of Metaphysics / 2. Possibility of Metaphysics
Kant turned metaphysics into epistemology, ignoring Aristotle's 'being qua being'
                        Full Idea: Kant turned the question 'How is metaphysics possible?' into 'How is metaphysical knowledge possible?' He thus turned metaphysics into epistemology, obliterating Aristotle's distinction between being qua being and being qua known.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Cynthia Macdonald - Varieties of Things Ch.1
                        A reaction: This makes Kant the number one villain in my philosophical pantheon, although the confusion of ontology and epistemology is found in Berkeley and others. Human speculations are not pointless, though they are difficult to verify.
Metaphysics might do better to match objects to our cognition (and not start with the objects)
                        Full Idea: Up to now it has been assumed that all our cognition must conform to the objects; ...let us try whether we do not get farther with problems of metaphysics by assuming that the objects must conform to cognition.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B Pref xvi)
                        A reaction: Kant compares this to rethinking our viewpoint on the solar system, and Gardner calls this idea Kant's 'Copernican Revolution'. We can only applaud the idea that we should be more self-conscious when we assess reality. Just don't give up on reality!
You just can't stop metaphysical speculation, in any mature mind
                        Full Idea: In all men, as soon as their reason has become ripe for speculation, there has always existed and will always continue to exist some kind of metaphysics.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B021)
                        A reaction: I love the word 'speculation' in this, because it is the part of metaphysics which always resists logical positivist scepticism about metaphysics. So what if you can't 'verify' it?
The voyage of reason may go only as far as the coastline of experience reaches
                        Full Idea: The voyage of our reason may proceed only as far as the continuous coastline of experience reaches.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B406-/A395)
                        A reaction: This is a strikingly empiricist remark, coming from Kant. It is certainly a firm rejection of what we might call 'speculative metaphysics', but allows what Peter Strawson calls 'descriptive metaphysics'. Cf. Idea 3722.
1. Philosophy / E. Nature of Metaphysics / 3. Metaphysical Systems
It is still possible to largely accept Kant as a whole (where others must be dismantled)
                        Full Idea: Unusually, Kant's system has continued to seem possible, to some degree, to endorse as a whole, as opposed to an edifice that has most to offer by being dismantled.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Sebastian Gardner - Kant and the Critique of Pure Reason 10 Intro
                        A reaction: I think Aristotle passes this test, but Plato has to be dismantled. No one ever swallows Leibniz whole. I suppose Hume can be taken complete, but only because of his minimal commitments.
Human reason considers all knowledge as belonging to a possible system
                        Full Idea: Human reason is by nature architectonic, i.e. it considers all cognitions as belonging to a possible system, and hence it permits only such principles as do not render an intended cognition incapable of standing together with others in some system.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B502/A474)
                        A reaction: Speak for yourself! However, there is no denying that the making connections seems basic to thought, and there is clearly an enticing magic in making lots of extended connections. Beautiful finished structures may, though, be coherent but false.
Reason has two separate objects, morality and freedom, and nature, which ultimately unite
                        Full Idea: The legislation of human reason (philosophy) has two objects, nature and freedom, and thus contains the natural law as well as the moral law, initially in two separate systems, but ultimately in a single philosophical system.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B868/A840)
                        A reaction: Pure reason is for nature, and practical reason (which has priority) is for freedom and morality. There is a streak of religiosity in Kant which makes him give morality and normativity priority over truth and science.
1. Philosophy / E. Nature of Metaphysics / 5. Metaphysics beyond Science
Kant showed that theoretical reason cannot give answers to speculative metaphysics
                        Full Idea: In the 'Critique of Pure Reason' Kant shows that theoretical reason is unable to answer the questions of speculative metaphysics.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Christine M. Korsgaard - Intro to 'Creating the Kingdom of Ends' 'Intro'
                        A reaction: I don't think I really agree with Kant. We can draw very extended inferences from experience, but the process rapidly becomes exceedingly difficult. The concepts we have built up are rather piecemeal, and not really designed for the job.
A priori metaphysics is fond of basic unchanging entities like God, the soul, Forms, atoms…
                        Full Idea: Kant stresses that reason, when it turns dialectical, posits immutable basic entities; these are the standard inhabitants of traditional a priori metaphysics - God, souls, Platonic ideas, Democritean indestructible atoms, and the like.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Robert Fogelin - Walking the Tightrope of Reason Ch.3
                        A reaction: This sounds like a good warning, but it just invites the meta-question in a priori metaphysics 'Are we searching for something unchanging, or is this impossible?' Aristotle certainly addressed this question. The search strikes me as sensible.
A dove cutting through the air, might think it could fly better in airless space (which Plato attempted)
                        Full Idea: The light dove, in free flight cutting through the air the resistance of which it feels, could get the idea that it could do even better in airless space. ..Plato made no headway in the empty space of understanding; he had no resistance, no support.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B008/A5)
                        A reaction: Who says Kant can't write? This is the classic image of the excesses of metaphysics which Kant wished to curtail. His attacks culminates in the contempt of logical positivism for such things, but no one would now disagree with Kant on this.
1. Philosophy / E. Nature of Metaphysics / 7. Against Metaphysics
Kant exposed the illusions of reason in the Transcendental Dialectic
                        Full Idea: The truly critical part of his First Critique was the Transcendental Dialectic; there Kant exposed the Illusions of Reason.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Bas C. van Fraassen - The Empirical Stance 1.1
1. Philosophy / F. Analytic Philosophy / 4. Conceptual Analysis
Our reason mostly analyses concepts we already have of objects
                        Full Idea: A great part, perhaps the greatest part, of the business of our reason consists in analyses of the concepts that we already have of objects.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B009/A5)
                        A reaction: I am quite happy to think of this as the central and crucial aspect of philosophy, though I am much more sceptical about purely linguistic analysis, as developed by Frege and Russell. It describes much of what Aristotle did.
Analysis of our concepts is merely a preparation for proper a priori metaphysics
                        Full Idea: The mere analysis of the concepts that inhabit our reason a priori, is not the end at all, but only a preparation for metaphysics proper, namely extending its a priori cognition sythetically.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B023)
                        A reaction: This seems to be evidence that Kant is not an 'analytical' philosopher, because he is willing to speculate, but that is a narrow twentieth century view of analysis. I take the aim to be an analysis of reality, not of human thought.
Analysis is becoming self-conscious about our concepts
                        Full Idea: To analyze a concept is to become self-conscious of the manifold that I always think in it.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B011/A7)
2. Reason / A. Nature of Reason / 1. On Reason
The boundaries of reason can only be determined a priori
                        Full Idea: The determination of the boundaries of our reason can only take place in accordance with a priori grounds
                        From: Immanuel Kant (Critique of Pure Reason [1781], B786/A758)
                        A reaction: I suspect that this is right, and is a truth of huge importance for philosophy. If we experience limitations in our reason (a not unusual experience!) this could never show that the boundary was necessary. This supports a minimal rationalism.
If I know the earth is a sphere, and I am on it, I can work out its area from a small part
                        Full Idea: If I know that the earth is a sphere, and its surface the surface of a sphere, then from a small part of the latter I can know the diameter, and hence the complete boundary, and in accordance with a priori principles.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B787/A757)
                        A reaction: A nice example, though it may be optimistic in its assumption that you can know you are on a sphere rather than an egg-shape. I agree with Kant, but speculative metaphysics should always be accompanied by humility and health warnings.
In reason things can only begin if they are voluntary
                        Full Idea: In reason itself nothing begins, but as the unconditioned condition of very voluntary action.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B582/A554)
                        A reaction: Kant's way of saying that free will is essential for pure reason. I can't quite digest 'pure' reason, but it is undeniable that rational processes seem to have rules of their own, and to arise entirely from the world of ideas, and not from the physical.
2. Reason / A. Nature of Reason / 3. Pure Reason
Pure reason deals with concepts in the understanding, not with objects
                        Full Idea: Pure reason is never related directly to objects, but instead to concepts of them given by the understanding.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B392/A335)
                        A reaction: Hence the keen interest of McDowell and others in the way in which concepts connect us into reality. Clearly a primrose path to anti-realism beckons here. I agree with Kant. Reason needs tokens to manipulate.
Pure reason exists outside of time
                        Full Idea: Pure reason, as a merely intelligible faculty, is not subject to the form of time, and hence not subject to the conditions of the temporal sequence.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B579/A551)
                        A reaction: A strong assertion of the notion of 'pure' reason. If it is outside time, it is presumably outside space-time, and so outside space. If I believed in it (and you can't really, can you?), I think I would go the whole hog, and add Platonism.
Reason hates to be limited in its speculations
                        Full Idea: Reason does not gladly suffer constraint in the paroxysms of its lust for speculative expansion.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B814/A786)
                        A reaction: This uncharacteristic outburst shows Kant's great commitment to the limitations of reason, despite his constant assertions that it is 'pure', and that it is the basis of all value.
Pure reason is only concerned with itself because it deals with understandings, not objects
                        Full Idea: Pure reason is concerned with nothing but itself, and it can have no other concern, because what is given to it is not objects to be unified for the concept of experience, but cognitions of understanding to be unified for the concept of reason.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B708/A680)
                        A reaction: It is hard to accept this sharp division between 'understanding', which gets involved in experience, and this very "pure" reason, which seems in danger of solipsism, and is playing a private game. I think purity comes in degrees.
2. Reason / A. Nature of Reason / 4. Aims of Reason
Reason keeps asking why until explanation is complete
                        Full Idea: For Kant, theoretical reason, like practical reason, seeks the unconditioned: it keeps asking why until explanation is complete.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Christine M. Korsgaard - Aristotle and Kant on the Source of Value 8 'Kant'
                        A reaction: I love this idea. It is so important in philosophy of science, because some theorists say we should give up before our explanations are complete.
Religion and legislation can only be respected if they accept free and public examination
                        Full Idea: Religion and legislation ...excite a just suspicion against themselves, and cannot claim that unfeigned respect that reason grants only to that which has been able to withstand free and public examination.
                        From: Immanuel Kant (Critique of Pure Reason [1781], A Pref xi n)
                        A reaction: A wonderful statement of a core principle of the liberal enlightenment. I can't really relate to anyone who would reject this idea (in general). Legislation might have special circumstances (such as wartime).
All objections are dogmatic (against propositions), or critical (against proofs), or sceptical
                        Full Idea: All objections are dogmatic, critical or sceptical. A dogmatic objection is directed against a proposition, but a critical one is directed against a proof. ..The sceptical objection puts the proposition and its opposite over against one another as equals.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B406-/A388)
                        A reaction: This is a nice distinction, and I would think that the hallmark of a philosophical person is that they are always looking for critical objections, because they want beliefs to be supported by good reasons, not prejudices.
2. Reason / B. Laws of Thought / 2. Sufficient Reason
The principle of sufficient reason is the ground of possible experience in time
                        Full Idea: The principle of sufficient reason is the ground of possible experience, namely the objective cognition of appearances with regard to their relation in the successive series of time.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B246/A201)
                        A reaction: The argument to this claim from the necessity of succession in time looks unconvincing to me, but the principle of sufficient reason is deeply imbedded in the human mind. However, philosophers seem to feel it more strongly than other people.
Proof of the principle of sufficient reason cannot be found
                        Full Idea: A proof of the principle of sufficient reason has often been sought, but always in vain.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B265/A217)
                        A reaction: This might, of course, be because the principle is false. However it is quite a good candidate for an a priori, or even innate, principle of thought in rational beings. Gödel's Theorem suggests why the enterprise of proof would be doomed.
2. Reason / C. Styles of Reason / 1. Dialectic
The free dialectic opposition of arguments is an invaluable part of the sceptical method
                        Full Idea: The sceptical method can point to the dialectic as an example of the great utility of letting the arguments of reason confront one another in the most complete freedom
                        From: Immanuel Kant (Critique of Pure Reason [1781], B535/A507)
                        A reaction: An interesting link, between dialectic and the sceptical method. I would say it runs deeper, and that scepticism and the free opposition of arguments are both basic to the whole notion of reason. Reason requires freedom (though not free will).
2. Reason / D. Definition / 2. Aims of Definition
Definitions exhibit the exhaustive concept of a thing within its boundaries
                        Full Idea: To define properly means just to exhibit originally the exhaustive concept of a thing within its boundaries
                        From: Immanuel Kant (Critique of Pure Reason [1781], B755/A727)
                        A reaction: There is nothing in the concept of a 'definition' that requires it to be exhaustive, because some things are too vague. Define the 'south' of England. What are the 'boundaries', if the concept could shift in its extension?
2. Reason / D. Definition / 13. Against Definition
No a priori concept can be defined
                        Full Idea: Strictly speaking no concept given a priori can be defined, e.g. substance, cause, right, equity, etc.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B756/A728)
                        A reaction: A passing remark with large and interesting implications. A huge amount of ink has been spilled over whether to take concepts such as identity, truth, goodness and substance as 'basic', or reduce them to something else.
2. Reason / E. Argument / 2. Transcendental Argument
Transcendental cognition is that a priori thought which shows how the a priori is applicable or possible
                        Full Idea: Not every a priori cognition must be called transcendental, but only that by means of which we cognize that, and how certain representations (intuitions or concepts) are applied entirely a priori, or are possible.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B80/A56)
                        A reaction: Kant really wasn't good at expressing himself. I would describe this as either explanation, or as meta-thought.
'Transcendent' is beyond experience, and 'transcendental' is concealed within experience
                        Full Idea: Kant distinguished between the 'transcendent', which is wholly beyond experience, and the 'transcendental', which, although not strictly part of experience, is a structural feature imminent in it.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781], B353/A296) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 02 'Trans'
                        A reaction: This may be the most disastrous idea in western philosophy since Plato's theory of Forms. How can he claim special insight into the imminent structural features of his own experience, while admitting that he has no experience of these features?
Transcendental ideas require unity of the subject, conditions of appearance, and objects of thought
                        Full Idea: All transcendental ideas fall under three classes: the first contains the absolute unity of the thinking subject, the second the unity of conditions of appearance, the third the unity of the condition of all objects of thought in general.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B391/A334)
                        A reaction: This kind of claim makes me search the attic for my logical positivist shotgun. How does he KNOW these things? However we must grant him that experience 'binds' together in some way, and we think of persons and ideas as atomic.
2. Reason / E. Argument / 3. Analogy
Philosophical examples rarely fit rules properly, and lead to inflexibility
                        Full Idea: Giving examples most commonly damages the insight of the understanding, since they only seldom fulfil the condition of the rule under consideration, ..and in the end accustom us to use those rules more like formulas than like principles.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B173/A134)
                        A reaction: This is directly contrary to the belief of most people who study or teach philosophy in the English-speaking world, but it is an interesting challenge. Philosophy is mainly concerned with abstract ideas. Maybe we need many examples, or none.
3. Truth / C. Correspondence Truth / 1. Correspondence Truth
We must presuppose that truth is agreement of cognition with its objects
                        Full Idea: The nominal definition of truth, namely that it is agreement of cognition with its objects, is here granted and presupposed; but one demands to know what is the general and certain criterion of the truth of any cognition.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B082/A58)
                        A reaction: I am puzzled by the second part of this, as the demand for a criterion (or justification) seems to me to have no part at all in our notion of what truth is in itself. It is a puzzle that Kant seems to accept the concept of truth used by simple realists.
4. Formal Logic / B. Propositional Logic PL / 2. Tools of Propositional Logic / e. Axioms of PL
Philosophy has no axioms, as it is just rational cognition of concepts
                        Full Idea: Since philosophy is merely rational cognition in accordance with concepts, no principle is to be encountered in it that deserves the name of axiom.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B760/A732)
                        A reaction: This is an attack on traditional rationalism, which aspires to do philosophy in the style of Euclid. Kant offers, however, a very conservative view, in which all concepts are 'given'. Nowadays we want to play with new axioms, as they did in geometry.
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
Logic has precise boundaries, and is the formal rules for all thinking
                        Full Idea: The boundaries of logic are determined quite precisely by the fact that logic is the science that exhaustively presents and strictly proves nothing but the formal rules of all thinking.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B Pref ix)
                        A reaction: Presumably it does not give the rules for ridiculous thinking, so more will be required. The interesting bit is the universality of the claim.
5. Theory of Logic / I. Semantics of Logic / 2. Formal Truth
There must be a general content-free account of truth in the rules of logic
                        Full Idea: Concerning the mere form of cognition (setting aside all content), it is equally clear that a logic, so far as it expounds the general and necessary rules of understanding, must present criteria of truth in these very rules.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B084/A59)
                        A reaction: A vital point, used by Putnam (Idea 2332) in his critique of machine functionalism. It is hard to see how we can think of logic as pure syntax if the concept of truth is needed. We may observe one Venn circle inside another, but interpretaton is required.
5. Theory of Logic / L. Paradox / 3. Antinomies
The battle of the antinomies is usually won by the attacker, and lost by any defender
                        Full Idea: These sophistical assertions [the antinomies] open us a dialectical battlefield where each party will keep the upper hand as long as it is allowed to attack, and will certainly defeat that which is compelled to conduct itself merely defensively.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B450/A423)
                        A reaction: This seems related to the interesting question of where the 'onus of proof' lies in a major dispute. Kant's implication is that the battles are not rational, if they are settled in such a fashion.
6. Mathematics / A. Nature of Mathematics / 2. Geometry
Geometry studies the Euclidean space that dictates how we perceive things
                        Full Idea: For Kant, geometry studies the forms of perception in the sense that it describes the infinite space that conditions perceived objects. This Euclidean space provides the forms of perception, or, in Kantian terms, the a priori form of empirical intuition.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Stewart Shapiro - Thinking About Mathematics 4.2
                        A reaction: We shouldn't assume that the discovery of new geometries nullifies this view. We evolved in small areas of space, where it is pretty much Euclidean. We don't perceive the curvature of space.
Geometry would just be an idle game without its connection to our intuition
                        Full Idea: Were it not for the connection to intuition, geometry would have no objective validity whatever, but be mere play by the imagination or the understanding.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B298/A239), quoted by Stewart Shapiro - Thinking About Mathematics 4.2
                        A reaction: If we pursue the idealist reading of Kant (in which the noumenon is hopelessly inapprehensible), then mathematics still has not real application, despite connection to intuition. However, Kant would have been an intuitionist, and not a formalist.
Geometrical truth comes from a general schema abstracted from a particular object
                        Full Idea: Kant explains the general validity of geometrical truths by maintaining that the particularity is genuine and ineliminable but is used as a schema. One abstracts from the particular elements of the objects of intuition in forming a general object.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781], B741/A713) by Tyler Burge - Frege on Apriority (with ps) 4
                        A reaction: A helpful summary by Burge of a rather wordy but very interesting section of Kant. I like the idea of being 'abstracted', but am not sure why that must be from one particular instance [certainty?]. The essence of triangles emerges from comparisons.
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / c. Potential infinite
Kant only accepts potential infinity, not actual infinity
                        Full Idea: For Kant the only legitimate infinity is the so-called potential infinity, not the actual infinity.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by James Robert Brown - Philosophy of Mathematics Ch.5
                        A reaction: This is part of what leads on the the Constructivist view of mathematics. There is a procedure for endlessly continuing, but no procedure for arriving. That seems to make good sense.
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
Euclid's could be the only viable geometry, if rejection of the parallel line postulate doesn't lead to a contradiction
                        Full Idea: The possible denial of the parallel lines postulate does not entail that Kant was wrong in considering Euclid's the only viable geometry. If the denial issued in a contradiction, then the postulate would be analytic, and Kant would be refuted.
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by José A. Benardete - Metaphysics: the logical approach Ch.18
6. Mathematics / B. Foundations for Mathematics / 4. Axioms for Number / a. Axioms for numbers
Kant suggested that arithmetic has no axioms
                        Full Idea: Kant suggested that arithmetic has no axioms.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781], B204-6/A164) by Stewart Shapiro - Thinking About Mathematics 4.2
                        A reaction: A hundred years later a queue was forming to spell out the axioms of arithmetic. The definitions of 0 and 1 always look to me more like logicians' tricks than profound truths. Some notions of successor and induction do, however, seem needed.
Axioms ought to be synthetic a priori propositions
                        Full Idea: Concerning magnitude ...there are no axioms in the proper sense. ....Axioms ought to be synthetic a priori propositions.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B205/A164)
                        A reaction: This may be a hopeless dream, but it is (sort of) what all philosophers long for. Post-modern relativism may just be the claim that all axioms are analytic. Could a posteriori propositions every qualify as axioms?
6. Mathematics / C. Sources of Mathematics / 2. Intuition of Mathematics
Kant's intuitions struggle to judge relevance, impossibility and exactness
                        Full Idea: Kant's intuitions have the Irrelevance problem (which structures of the mind are just accidental?), the Practical Impossibility problem (how to show impossible-in-principle?), and the Exactness problem (are entities exactly as they seem?).
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Philip Kitcher - The Nature of Mathematical Knowledge 03.1
                        A reaction: [see Kitcher for an examination of these] Presumably the answer to all three must be that we have meta-intuitions about our intuitions, or else intuitions come with built-in criteria to deal with the three problems. We must intuit something specific.
6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / a. Mathematical empiricism
Maths is a priori, but without its relation to empirical objects it is meaningless
                        Full Idea: Although all these principles .....are generated in the mind completely a priori, they would still not signify anything at all if we could not always exhibit their significance in appearances (empirical objects).
                        From: Immanuel Kant (Critique of Pure Reason [1781], B299/A240)
                        A reaction: This is the subtle Kantian move that we all have to take seriously when we try to assert 'realism' about anything. Our drive for meaning creates our world for us?
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
Kant taught that mathematics is independent of logic, and cannot be grounded in it
                        Full Idea: Kant taught - and it is an integral part of his doctrine - that mathematics treats a subject matter which is given independently of logic. Mathematics, therefore, can never be grounded solely in logic.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by David Hilbert - On the Infinite p.192
                        A reaction: Presumably Gödel's Incompleteness Theorems endorse the Kantian view, that arithmetic is sui generis, and beyond logic.
If 7+5=12 is analytic, then an infinity of other ways to reach 12 have to be analytic
                        Full Idea: Kant claimed that 7+5=12 is synthetic a priori. If the concept of 12 analytically involves knowing 7+5, it also involves an infinity of other arithmetical ways to reach 12, which is inadmissible.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781], B205/A164) by Jonathan Dancy - Intro to Contemporary Epistemology 14.3
7. Existence / A. Nature of Existence / 1. Nature of Existence
Saying a thing 'is' adds nothing to it - otherwise if my concept exists, it isn't the same as my concept
                        Full Idea: We do not make the least addition to a thing when we declare the thing 'is'. Otherwise it would not be exactly the same thing that exists, but something more than we had thought in the concept, so we could not say the exact object of my concept exists.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B628/A600)
                        A reaction: This still strikes me as a wonderful objection to the ontological argument for God. It raises the question of what 'is' does mean. Is it a 'quantifier'? What is the ontological status of a quantifier?
7. Existence / D. Theories of Reality / 2. Realism
Kant is read as the phenomena being 'contrained' by the noumenon, or 'free-floating'
                        Full Idea: The two readings of Kant depend on whether the world of phenomena is 'constrained' by the noumenon, or whether it is 'free-floating'.
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Marianne Talbot - talk
                        A reaction: The free-floating reading leads to idealism, since the noumenon then becomes a quite irrelevant part of Kant's theory, and can be dropped (since its existence means nothing if it has no causal role). On the first reading, constraint becomes interesting.
7. Existence / D. Theories of Reality / 4. Anti-realism
Without the subject or the senses, space and time vanish, as their appearances disappear
                        Full Idea: If we remove our own subject or even ....the senses in general, then all the constitution, all relations of objects in space and time, indeed space and time themselves would disappear, and as appearances they cannot exist in themselves, but only in us.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B059/A42)
                        A reaction: This is as clear a statement of anti-realist idealism as I have ever found in Kant. You can interpret him as a thorough scientific realist, but you have to put a tricky spin on passages like this. Or maybe only the 'appearances' of space and time vanish?
Even the most perfect intuition gets no closer to things in themselves
                        Full Idea: Even if we could bring this intuition of ours to the highest degree of distinctiveness we would not thereby come any closer to the constitution of objects in themselves.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B060/A43)
                        A reaction: Either slightly ridiculous anti-realism, or a self-evident platitude. Personally I think I know the reality of trees pretty well, but to totally embrace their constitution I would have to become a tree (an Ent). My experience of me is only partial.
7. Existence / E. Categories / 1. Categories
Categories are general concepts of objects, which determine the way in which they are experienced
                        Full Idea: The categories are the concepts of an object in general, by means of which its intuition is regarded as determined with regard to one of the logical functions of government.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B128/A95)
                        A reaction: These are Kant's 'transcendental' categories. I'm wondering what he made of our more normal categories, such as animal species, genera etc.
Categories are necessary, so can't be implanted in us to agree with natural laws
                        Full Idea: If one proposed a middle way, that categories are subjective predispositions for thinking, implanted in us so that their use would agree exactly with the laws of nature,..then the categories would lack the necessity which is essential to their concept.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B167)
                        A reaction: Kant might want to rethink this once he got the hang of the theory of evolution. If we have innate categories, they must have some survival value. I don't understand Kant's claim that the categories are necessary. They just reflect nature.
7. Existence / E. Categories / 2. Categorisation
Does Kant say the mind imposes categories, or that it restricts us to them?
                        Full Idea: It is unclear whether Kant says the mind imposes space and time and categories, such as substance and cause and effect, on empirical objects, or whether our mind restricts our cognition to such features of noumenal objects. Imposition, say the majority.
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Mark Rowlands - Externalism Ch.3
                        A reaction: Rowlands says, rightly, that Kant probably thought the mind imposed categories, but that he should have said that it restricts us to them. The imposition view leads to idealism, anti-realism and madness; restriction is common sense, really.
8. Modes of Existence / C. Powers and Dispositions / 7. Against Powers
Kant claims causal powers are relational rather than intrinsic
                        Full Idea: Kant argues that an object's causal powers are not intrinsic to it but feature among its relational properties.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Tim Bayne - Thought: a very short introduction Ch.7
                        A reaction: [He doesn't give a reference for this] Put in this simple way, rather than obfuscated by Kant's arcane lexis, this sounds utterly false to me. Giving relations and functions explains nothing. How are those relations and functions possible?
9. Objects / A. Existence of Objects / 1. Physical Objects
Objects in themselves are not known to us at all
                        Full Idea: Objects in themselves are not known to us at all.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B045/A30)
                        A reaction: It is the phrase "at all" which is interesting. It suggests that Kant is in no way a representative realist, though it is hard to place him within the labels of phenomenalism/idealism/anti-realism.
The a priori concept of objects in general is the ground of experience
                        Full Idea: Concepts of objects in general lie at the ground of all experiential cognition as a priori conditions.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B126/A93)
                        A reaction: Does Kant have an a priori insight that process philosophy, or philosophy based entirely on relations, are wrong?
9. Objects / B. Unity of Objects / 2. Substance / a. Substance
A substance could exist as a subject, but not as a mere predicate
                        Full Idea: A substance is something that could exist as a subject but never as a mere predicate.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B149)
                        A reaction: Interesting to see Kant asserting the idea of substance a century after many philosophers thought they had dispensed with this Aristotelian notion (e.g. Ideas 3628 and Idea 2714). It has crept back into modern metaphysics too (e.g. in Wiggins).
9. Objects / B. Unity of Objects / 2. Substance / d. Substance defined
All appearances need substance, as that which persists through change
                        Full Idea: All appearances contain that which persists (substance) as the object itself, and that which can change as its mere determination (i.e. the way in which the object exists). ...[2nd ed] In all change of appearances substance persists.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B224/A182)
                        A reaction: This is a full-blooded commitment by Kant to the traditional Aristotelian concept of a substance which endures through the change in its accidental features. Though in Kant's case the commitment is 'transcendental', not realist.
Substance must exist, as the persisting substratum of the process of change
                        Full Idea: Since all effect consists in that which happens, consequently in the changeable, which indicates succession in time, the ultimate subject of the changeable is therefore that which persists, as the substratum of everything that changes, i.e. the substance.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B250/A205)
                        A reaction: The idea that 'something' changes seems to involve a commitment to substances, but not if one thing is replaced by another. It is not clear that the abandonment of the concept of substance leads to a total collapse of our metaphysics.
9. Objects / E. Objects over Time / 1. Objects over Time
An a priori principle of persistence anticipates all experience
                        Full Idea: The principle of persistence is one that anticipates experience just as much as that of causality.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B795/A767)
                        A reaction: This is the notion that identity is an indefinable basic of our understanding. He is objecting to Hume, who, of course, thought persistance was just an experience. Personally I persistance to be a posteriori, but how else could things exist?
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
The Identity of Indiscernibles is true of concepts with identical properties, but not of particulars
                        Full Idea: Kant said that the principle of the Identity of Indiscernibles is true only at the level of concepts; two concepts having identical properties are the same concept; the principle is not true at the level of particulars given in sensory experience.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Nicholas Jolley - Leibniz Ch.8
                        A reaction: Good. I would think that should be the last word on that particular subject. ...Suppose, though, that two people had identical concepts with identical properties, but believed that the extensions (application to particulars) were different?
If we ignore differences between water drops, we still distinguish them by their location
                        Full Idea: In the case of two drops of water one can completely abstract from all inner difference (of quality and quantity), and it is enough that they be intuited in different places at the same time in order for them to be held to be numerically different.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B319/A263)
                        A reaction: Adams points out that this is the same idea as Max Black's famous two spheres thought experiment. We assume that all the water drops are distinct from one another, even if we are unable to perceive the fact. Best explanation.
10. Modality / A. Necessity / 1. Types of Modality
Modalities do not augment our concepts; they express their relation to cognition
                        Full Idea: The categories of modality have this peculiarity: as a determination of the object they do not augment the concept to which they are ascribed in the least, but rather express only the relation to the faculty of cognition.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B266/A219)
                        A reaction: A nice summary of Kant's view of modality. It does not arise out of reality, or even out of the nature of our concepts, but out of the relations which our concepts enter into, in the processes of understanding. (Do I understand that?)
10. Modality / A. Necessity / 7. Natural Necessity
Natural necessity is the unconditioned necessity of appearances
                        Full Idea: The unconditioned necessity of appearances can be called natural necessity.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B447/A419)
                        A reaction: Kant can call it what he likes, but this isn't what we mean by 'natural necessity'. We mean a feature of reality, even if we can only use appearances to infer that feature. As usual, they can't tell their ontology from their epistemology.
10. Modality / B. Possibility / 1. Possibility
A concept is logically possible if non-contradictory (but may not be actually possible)
                        Full Idea: The concept is always possible if it does not contradict itself (the logical mark of possibility). Yet it can be an empty concept. ...We cannot infer from the possibility of the concept (logical possibility) to the possibility of the thing (real).
                        From: Immanuel Kant (Critique of Pure Reason [1781], B624/A596 n)
Is the possible greater than the actual, and the actual greater than the necessary?
                        Full Idea: Whether the field of possibility is greater than the field that contains everything actual, and whether the latter is in turn greater than the set of that which is necessary, are proper questions.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B282/A230)
                        A reaction: A good overview. Is the actual necessary (i.e. is only the actual possible?)? Why is the non-actual possible? What would a theory look like which explains why the necessary is necessary, the actual actual, and the possible possible? A religion?
The analytic mark of possibility is that it does not generate a contradiction
                        Full Idea: The analytic mark of possibility is the fact that mere positings (realities) do not generate a contradiction.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B630/A602)
                        A reaction: I think this is wrong. I would offer self-evident absurdity (but with no actual contradiction) as another analytic mark of possibility. Natural possibility may coincide with metaphysical possibility. Human thought does not determine possibilities.
10. Modality / C. Sources of Modality / 4. Necessity from Concepts
Formal experience conditions show what is possible, and general conditions what is necessary
                        Full Idea: Whatever agrees with the formal conditions of experience is possible, ...and that whose connection with the actual is determined in accordance with general conditions of experience is (exists) necessarily.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B266/A218)
                        A reaction: This is the Kantian view of necessity, as more concerned with how we think than with how the world is. I think there are necessities in reality, and philosophy endeavours to discern what they are (despite the mockery of scientists).
10. Modality / D. Knowledge of Modality / 1. A Priori Necessary
Kant thought worldly necessities are revealed by what maths needs to make sense
                        Full Idea: It struck Kant (to put it crudely) that there are some things which are necessarily true of the world, revealed when we consider what is required for mathematics - indeed, thinking in general - to make sense.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Michael Morris - Guidebook to Wittgenstein's Tractatus Intro
                        A reaction: This is given as background the Wittgenstein's Tractatus. He disagrees with Kant because logic is not synthetic. I see a strong connection with the stoic belief that the natural world is intrinsically rational.
Necessity is always knowable a priori, and what is known a priori is always necessary
                        Full Idea: The Kantian rationalist view is that what is necessary is always knowable a priori, and what is knowable a priori is always necessary.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Laura Schroeter - Two-Dimensional Semantics 2.3.1
                        A reaction: Nice to get a clear spelling out of the two-way relationship here. Why couldn't Kant put it as clearly as this? See Kripke for the first big challenges to Kant's picture. I like aposteriori necessities.
For Kant metaphysics must be necessary, so a priori, so can't be justified by experience
                        Full Idea: Kant maintained that metaphysics must be a body of necessary truths, and that necessary truths must be a priori, so metaphysical claims could not be justified by experience.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Tim Maudlin - The Metaphysics within Physics 3
                        A reaction: I'm coming to the view that there is no a priori necessity, and that all necessities are entailments from the nature of reality. The apparent a priori necessities are just at a very high level of abstraction.
Maths must be a priori because it is necessary, and that cannot be derived from experience
                        Full Idea: Mathematical propositions are always a priori judgments and are never empirical, because they carry necessity with them, which cannot be derived from experience.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B014)
                        A reaction: Personally I like the idea that maths is the 'science of patterns', but then I take it that the features of patterns will be common to all possible worlds. Presumably a proposition could be contingent, and yet true in all possible worlds.
11. Knowledge Aims / A. Knowledge / 1. Knowledge
Knowledge is threefold: apprehension, reproduction by imagination, recognition by concepts
                        Full Idea: Kant describes knowledge in terms of a 'threefold synthesis', in which something is first 'apprehended' as affecting the mind, then is 'reproduced' in the imagination, and finally is 'recognised' via a concept which classifies it.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Andrew Bowie - Introduction to German Philosophy 1 'Judgement'
                        A reaction: Helpful. How does this distinguish knowledge from error (as Russell would enquire)? Is the 'apprehended', then, the unconceptualised 'Given'? I think that is what later German philosophers rebelled against in Kant.
Knowledge begins with intuitions, moves to concepts, and ends with ideas
                        Full Idea: All human cognition begins with intuitions, goes from there to concepts, and ends with ideas.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B730/A702)
                        A reaction: 'Ideas' is a vague term. 'Propositions' might fit better. The question is whether concept-free intuitions are possible. They sound here like Humean 'impressions'. The brain phenomenon of re-entry suggests that ideas in turn influence intuitions.
11. Knowledge Aims / A. Knowledge / 2. Understanding
Kant showed that the understanding (unlike reason) concerns what is finite and conditioned
                        Full Idea: Kant was the first to emphasize the distinction between understanding and reason in a definite way, establishing the finite and conditioned as the subject-matter of the former, and the infinite and unconditioned as that of the latter.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Georg W.F.Hegel - Logic (Encyclopedia I) §45 Add
                        A reaction: This seems to match Plato's division of reality into the realm of experience and of the mind. I am inclined to see them as a unity, united by the many levels of abstraction. Frege is the modern spokesman for the Plato/Hegel view.
Understanding essentially involves singular elements
                        Full Idea: For Kant understanding essentially involves singular elements (and reason is essentially general).
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Tyler Burge - Frege on Apriority (with ps) 3
Reason is distinct from understanding, and is the faculty of rules or principles
                        Full Idea: In the first part of our transcendental logic we defined the understanding as the faculty of rules; here we will distinguish reason from understanding by calling reason the faculty of principles.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B356/A299)
                        A reaction: If we narrow the concept of rationality down to a concern with rules or principles, the concept of 'understanding' has to widen out to cover inferences from experience. Personally I think we can be rational about particulars as well as principles.
11. Knowledge Aims / A. Knowledge / 4. Belief / a. Beliefs
Opinion is subjectively and objectively insufficient; belief is subjective but not objective; knowledge is both
                        Full Idea: An 'opinion' is taking something to be true which is subjectively and objectively insufficient. 'Believing' is when it is subjectively sufficient and objectively insufficient. 'Knowing' is subjective and objective sufficiency (for myself, and everyone).
                        From: Immanuel Kant (Critique of Pure Reason [1781], B850/A822)
                        A reaction: He defines objectivity as being 'sufficient' for 'everyone'. Compare Aristotle's Idea 95. This implies a rather social criterion for knowledge, but doesn't deal with 'sufficient for a majority, but not everyone'. How high to set the bar?
11. Knowledge Aims / B. Certain Knowledge / 5. Cogito Critique
'I think therefore I am' is an identity, not an inference (as there is no major premise)
                        Full Idea: My existence cannot be regarded as inferred from the proposition "I think" (for otherwise the major premise "Everything that thinks, exists" would have to precede it), but rather it is identical with it.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B422)
                        A reaction: "I think" can hardly be identical with "I exist". One is an activity, the other a state. I prefer: within the unified activity of thinking which is clearly occurring, it is self-evident that there must be an 'I' which holds it together.
11. Knowledge Aims / C. Knowing Reality / 2. Phenomenalism
There are possible inhabitants of the moon, but they are just possible experiences
                        Full Idea: That there could be inhabitants of the moon, even though no human being has ever perceived them, must of course be admitted; but this means only that in the possible progress of experience we could encounter them.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B521/A493)
                        A reaction: This seems a fairly precise statement of phenomenalism (compare A.J. Ayer's Idea 5170). Kant calls himself a 'transcendental idealist', which seems something like a true idealist who acknowledges Humean 'natural beliefs' in reality.
11. Knowledge Aims / C. Knowing Reality / 3. Idealism / a. Idealism
We have no sensual experience of time and space, so they must be 'ideal'
                        Full Idea: Time and space, Kant concluded, were 'ideal' since they could not be objects of direct sensory experience, and therefore had to be available only as 'pure' representations. ...Hence time and space were not 'objects' out there in the world.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Terry Pinkard - German Philosophy 1760-1860 01
                        A reaction: Put like this it sounds like a crazy application of empiricism, but demanding that space and time are experienced by the 'senses'. Can't we way that we experience them, but not through any particular sense? Kant at his most idealist.
Objects having to be experiencable is not the same as full idealism
                        Full Idea: Being subject to the condition of experienceability - that is, necessarily related in some manner to intuition - is not the same as being composed of experiences in any sense (and particularly Berkeley's sense).
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Sebastian Gardner - Kant and the Critique of Pure Reason 08 'Non-phenom'
                        A reaction: This is Gardner's best explanation of why Kant is definitely not a Berkeleyan idealist (who claims objects ARE conscious experiences)
If we disappeared, then all relations of objects, and time and space themselves, disappear too
                        Full Idea: If we remove our own subject ...then all the constitution, all relations of objects in space and time, indeed space and time themselves would disappear, and as appearances they cannot exist in themselves, but only in us.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B059/A42)
                        A reaction: Apart from over-cautious 'as appearances', this seems like simple Berkleyean idealism, and hence rather silly. The first commitment of realism (mine, anyway) is that at least time and space would survive our disappearance.
11. Knowledge Aims / C. Knowing Reality / 3. Idealism / b. Transcendental idealism
Kant's idealism is a limited idealism based on the viewpoint of empiricism
                        Full Idea: Kant's idealism is a limited idealism - idealism based on the viewpoint of empiricism.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Ludwig Feuerbach - Principles of Philosophy of the Future §17
                        A reaction: This would place Kant as closer to Berkeley than to Hegel. Good for Kant, I say. He had the good sense to see that the crucial challenge to understanding is that offered by David Hume.
In Kantian idealism, objects fit understanding, not vice versa
                        Full Idea: In Kantian idealism, the objects conform to the understanding, and not the understanding to the objects.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Ludwig Feuerbach - Principles of Philosophy of the Future §17
                        A reaction: This labels Kant as an idealist, but he was also a realist (of a very minimal sort). Modern cognitive science shows clearly that Kant is at least partially correct. Personally I think I see squares as square because they are square.
For Kant experience is either structured like reality, or generates reality's structure
                        Full Idea: On the analytic interpretation of Kant (by Strawson) ...the structure of experience ultimately reduces to the structure of what is experienced. ...In the idealist view (of D. Heinrich) experience itself has an inherent structure.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Sebastian Gardner - Kant and the Critique of Pure Reason 02 'Interpretations'
                        A reaction: Gardner thinks Strawson has got it wrong, and makes a good case for his view. Strawson's view sounds more like the empiricist view of concepts. I prefer that view, but I doubt whether it is Kant's.
The concepts that make judgeable experiences possible are created spontaneously
                        Full Idea: The concepts that make sensory experience possible are not innate, but are generated by the spontaneity of the human mind itself as it shapes our experiences in to judgemental form.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Terry Pinkard - German Philosophy 1760-1860 01
                        A reaction: Pinkard emphasises this creative spontaneity of the mind as a key idea in Kant, and in the generation that followed him. An account is needed of how the spontaneity matches reality, rather than being private. What about words (like 'telephone').
'Transcendental' cognition concerns what can be known a priori of its mode
                        Full Idea: I call all cognition 'transcendental' that is occupied not so much with objects but rather with our mode of cognition of objects insofar as this is to be possible a priori.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B025/A11)
                        A reaction: Kant thinks this enquiry is a highly rational affair, but it sounds more like hopeful introspective psychology to me. If you find some prerequisites for an activity, how do you know there aren't others you have missed?
We cannot know things in themselves, but are confined to appearances
                        Full Idea: We have no insight into the possibility of noumena (things in themselves), and the domain outside the sphere of appearances is empty (for us).
                        From: Immanuel Kant (Critique of Pure Reason [1781], B310/A255)
                        A reaction: Yet another philosopher confusing ontology and epistemology! Every day we go beyond our experiences by inference (smoke means fire). Metaphysics is the inference of the nature of things in themselves, from within our prison of appearances.
We have proved that bodies are appearances of the outer senses, not things in themselves
                        Full Idea: In the transcendental aesthetic we have undeniably proved that bodies are mere appearances of our outer senses, and not things in themselves.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B406-/A357)
                        A reaction: This seems a strongly idealistic remark, which is a bit qualified when he talks of the existence of the unknowable 'noumenon' behind appearances, and he rejects idealism when he labels it a 'paralogism' at A367, preferring 'transcendental idealism'.
Everything we intuit is merely a representation, with no external existence (Transcendental Idealism)
                        Full Idea: We have proved that everything intuited in space or time, hence all possible objects of experience, are nothing but appearances, mere representations, which ...have outside our thoughts no existence grounded in itself. I call this Transcendental Idealism.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B519/A491)
                        A reaction: It is only 'transcendental' idealism because it is what can be learned from deconstructing our own cognition, while remaining neutral (I assume) about whether the things-in-themselves are mere ideas. He is notoriousy ambivalent.
12. Knowledge Sources / A. A Priori Knowledge / 1. Nature of the A Priori
Kant's shift of view enables us to see a priority in terms of mental capacity, not truth and propositions
                        Full Idea: Kant's shift in his understanding of apriority from the content of truth and of proof-sequences of propositions to the character of cognitive procedures opens more possibilities for understanding the sources of apriority, in capacities and mental acts.
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Tyler Burge - Frege on Apriority I
                        A reaction: [Burge attributes the alternative view to Leibniz and Frege] This harmless-looking thought seems to me right at the heart of what I take to be a discrete cold war going on between logicians and philosophers. Logic is in retreat!
A priori knowledge is limited to objects of possible experience
                        Full Idea: Kant says that a priori knowledge is limited to objects of possible experience, and this is the core thesis of his distinctive doctrine of transcendental idealism.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Nicholas Jolley - Leibniz Ch.8
                        A reaction: Some people would even challenge this bold claim for a priori knowledge, but this idea shows why Kant was said to have put an end to old fashioned speculative metaphysics. For Kant, a priori knowledge seems to be something like introspection.
A priori knowledge occurs absolutely independently of all experience
                        Full Idea: We will understand by a priori cognitions not those that occur independently of this or that experience, but rather those that occur absolutely independently of all experience.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B003)
                        A reaction: Kitcher quotes this, and raises questions about how widely we should understand 'experience', and how strongly we can assert total 'independence'. But then he is attacking the whole idea of a priori knowledge. He modifies Kant's formulation (Idea 12415).
One sort of a priori knowledge just analyses given concepts, but another ventures further
                        Full Idea: Analysis of concepts affords us a multitude of cognitions which are illuminations or clarifications of what is already thought, and yields a priori cognition. Reason also surreptitiously makes a priori assertions, which add something alien to the concept.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B009/A5)
                        A reaction: This is at the heart of Kant's programme, to disentangle these two, and especially to turn a strong critical light on the second one. He does not deny the possibility of a priori knowledge beyond conceptual analysis, but is wary.
12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
Experienceless bodies have space; propertyless bodies have substance; this must be seen a priori
                        Full Idea: Remove from your experiential concept of a body everything empirical (colour, hardness etc), and there still remains its space. If you remove all the properties which experience teaches you, there remains substance. This shows your a priori faculty.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B006)
                        A reaction: Presumably you can also 'remove' the space and the substance. Maybe there are no actual items such as spaces or substances, so getting both of them wrong wouldn't be a good advertisement for the faculty. It's just imagination?
12. Knowledge Sources / A. A Priori Knowledge / 4. A Priori as Necessities
The apriori is independent of its sources, and marked by necessity and generality
                        Full Idea: Kant defines apriority in terms of independence from genesis and from sense experience, and it is indicated by its necessity and by it generality or universality.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781], B003-4) by Tyler Burge - Frege on Apriority (with ps) 2
Two plus two objects make four objects even if experience is impossible, so Kant is wrong
                        Full Idea: Two physical objects and two other physical objects must make four physical objects, even if physical objects cannot be experienced, so Kant's solution unduly limits the scope of a priori propositions.
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Bertrand Russell - Problems of Philosophy Ch.8
                        A reaction: The point seems good, though it is doubtful whether Russell is entitled to be so confident. If the basis of a priori certainty is pushed outside the mind, our ontology becomes dramatically more complicated.
Propositions involving necessity are a priori, and pure a priori if they only derive from other necessities
                        Full Idea: If a proposition is thought along with its necessity, it is an a priori judgement; if it is, moreover, also not derived from any proposition except one that in turn is valid as a necessary proposition, then it is absolutely a priori.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B003)
                        A reaction: The misunderstanding behind this is that we can obtain certainty in this way. I presume that consistency with empirical experience would increase our certainty of (say) maths or logic. There is no 'pure' a priori, delivering 'pure' necessity.
A priori knowledge is indispensable for the possibility and certainty of experience
                        Full Idea: One could establish the indispensability of the reality of pure a priori principles for the possibility of experience itself, and thus establish it a priori. Where would experience gets its certainty if it was based on empirical, contingent rules?
                        From: Immanuel Kant (Critique of Pure Reason [1781], B005)
                        A reaction: [compressed] There seems a touch of circularity here, apart from the transcendental argument. Proving the a priori by a priori means? All very odd. And experience is certain because it is based on a priori rules, which are necessary?
12. Knowledge Sources / A. A Priori Knowledge / 5. A Priori Synthetic
Seeing that only one parallel can be drawn to a line through a given point is clearly synthetic a priori
                        Full Idea: Kant took Euclidean geometry to be an obvious source of synthetic a prior truths, as one can just see that through a point outside a straight line one and only one parallel to it can be drawn.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by José A. Benardete - Metaphysics: the logical approach Ch.18
Kant bases the synthetic a priori on the categories of oneness and manyness
                        Full Idea: The categories of oneness and manyness are the basis of what Kant terms 'synthetic judgements a priori'.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Andrew Bowie - Introduction to German Philosophy 1 'First'
                        A reaction: This is a solution to the paradoxes of one and many that bothered Plato. I think it is best seen in our capacity to count things, and the individuation which must precede that. Atomism and holism.
Kant showed that we have a priori knowledge which is not purely analytic
                        Full Idea: Kant deserves credit for showing that we have a priori knowledge which is not purely 'analytic', i.e. such that the opposite would be self-contradictory.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Bertrand Russell - Problems of Philosophy Ch. 8
                        A reaction: It is noteworthy that a great empiricist philosopher makes this judgement. But how do you spot an a priori truth, apart from seeing that its opposite would be a contradiction? Where else can its force come from?
We can think of 7 and 5 without 12, but it is still a contradiction to deny 7+5=12
                        Full Idea: From the fact that one can think of the sum of seven and five without necessarily thinking of twelve, it by no means follows that the proposition '7+5=12' can be denied without self-contradiction.
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by A.J. Ayer - Language,Truth and Logic Ch.4
                        A reaction: Kant's claim that arithmetic was synthetic always looked glib and dubious, and this pinpoints an objection very nicely. It appears that the great Kant has confused his epistemology with his ontology.
That a straight line is the shortest is synthetic, as straight does not imply any quantity
                        Full Idea: That the straight line between two points is the shortest is a synthetic proposition. For my concept of the straight contains nothing of quantity, but only a quality. The concept of shortest is additional, and cannot be extracted by analysis.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B016)
                        A reaction: We should ask Kant to define 'straight' without mentioning 'shortest'. If you think of a long walk between two towns, it becomes obvious that the straight line will be defined by being the shortest line.
That force and counter-force are equal is necessary, and a priori synthetic
                        Full Idea: In the proposition that in all communication of motion effect and counter-effect must always be equal, not only the necessity, and thus its a priori origin, but also that it is a synthetic proposition is clear.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B017)
                        A reaction: No, I don't follow that. God might have made Newton's Third Law that every time you push a wall it pushes you back with double force. Looks like a Humean a posteriori observation of regularity to me.
The real problem of pure reason is: how are a priori synthetic judgments possible?
                        Full Idea: The real problem of pure reason is contained in the question: How are synthetic judgments a priori possible?
                        From: Immanuel Kant (Critique of Pure Reason [1781], B019)
                        A reaction: If they are possible, I would say that is not 'the real problem of pure reason', but the real problem of understanding the underlying nature of reality. I doubt whether we know much of reality by 'pure' reason, but we might 'see' that it is necessary.
That two lines cannot enclose a space is an intuitive a priori synthetic proposition
                        Full Idea: The proposition that with two straight lines no space can be enclosed cannot be derived from the concept of straight lines and the number two. You are forced to take refuge in intuition, ..which is a pure a priori intuition of a synthetic proposition.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B065/A47)
                        A reaction: A very nice example. If you gave a child two rods and told them to make a shape, they might quickly learn this from experience. Kant's proposal is nice, but I am not convinced. We learn that to create shapes you must turn corners.
Are a priori concepts necessary as a precondition for something to be an object?
                        Full Idea: The question is whether a priori concepts precede, as conditions under which alone something can be, if not intuited, nevertheless thought as objects in general.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B125/A93)
                        A reaction: This remains a good question. Some sort of synthesis of impressions is required in order to perceive an object. To think of it as a rational inference seems wildly wrong, as it is instantaneous. How do dogs get along, I wonder….
7+5=12 is not analytic, because 12 is not contained in 7 or 5 or their combination
                        Full Idea: 7+5=12 is not an analytic proposition, for I do not think the number 12 either in the representation of 7 nor in that of 5 nor in the representation of the combination of the two.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B205/A164)
                        A reaction: Unconvincing. The third option sounds analytic. Present it as: if you start at 7 and move 5 places along the natural number sequence, you have arrived at the answer (so find out its name). Or rename '12' as 'sevenplusfive'?
We possess synthetic a priori knowledge in our principles which anticipate experience
                        Full Idea: We are already in possession of synthetic a priori cognition, as is established by the principles of understanding, which anticipate experience.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B790/A762)
                        A reaction: When put like this, I remain unconvinced that the mental states to which Kant refers should actually qualify as cognition/knowledge. If we have to look through rose-tinted spectacles, this doesn't make rose-colour a truth, or even a belief.
12. Knowledge Sources / A. A Priori Knowledge / 6. A Priori from Reason
Reason contains within itself certain underived concepts and principles
                        Full Idea: Reason itself contains the origin of certain concepts and principles, which it derives neither from the senses nor from the understanding.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B355/A299)
                        A reaction: You might say that these principles are known 'by the natural light' rather than being innate, but if they are not even 'derived from the understanding', that seems to leave them innate, which is a classic hallmark of a rationalist philosopher.
12. Knowledge Sources / A. A Priori Knowledge / 7. A Priori from Convention
If, as Kant says, arithmetic and logic are contributed by us, they could change if we did
                        Full Idea: The main objection to Kant's philosophy is that to say that logic and arithmetic are contributed by us does not account for its certainty; if Kant is right, then tomorrow our nature could so change as to make two and two become five.
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Bertrand Russell - Problems of Philosophy Ch.8
                        A reaction: One would expect a realist like Russell to have fairly fundamental objections to the implied anti-realism (and conventionalism) of Kant. The same comment could be made about Kant's view of space, time and causation.
12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic
No analysis of the sum of seven and five will in itself reveal twelve
                        Full Idea: The concept of twelve is by no means already thought merely by my thinking of the unification of seven and five, and no matter how long I analyze my concept of such a possible sum I will still not find twelve in it.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B015)
                        A reaction: I don't find this convincing. All sums can be revealed by analysing the relationships within the sequence of natural numbers.
12. Knowledge Sources / A. A Priori Knowledge / 9. A Priori from Concepts
For Kant analytic knowledge needs complex concepts, but the a priori can rest on the simple
                        Full Idea: As Kant saw it, analytic knowledge is possible only in the presence of conceptual complexity, but it should have been clear that simple concepts, unaided by intuition, are as apt as their complex counterparts to act as grounds of a priori knowledge.
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by J. Alberto Coffa - The Semantic Tradition from Kant to Carnap 1 'Analyt'
                        A reaction: The point is that the concept must 'contain' something for Kant's account of what is analytic. This seems to be a very important thought for those who think the a priori is entirely analytic.
With large numbers it is obvious that we could never find the sum by analysing the concepts
                        Full Idea: It is clearer that all arithmetical propositions are synthetic if we take larger numbers, for it is then clear that, twist and turn our concepts as we will, without help from intuition we could never find the sum by means of the mere analysis of concepts.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B016)
                        A reaction: I don't see this. Obviously we may not know the name of the number which is the answer. We must analyse 'plus' as well as the component numbers. How can it be synthetic if no experience is involved?
12. Knowledge Sources / A. A Priori Knowledge / 10. A Priori as Subjective
A priori the understanding can only anticipate possible experiences
                        Full Idea: The understanding can never accomplish a priori anything more than to anticipate the form of a possible experience in general.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B303/A246)
                        A reaction: This is why many people think that Kant brough metaphysical (ontological) speculation to an end. He asserts that synthetic a priori knowledge is possible, but then imposes a huge limitation on it.
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / b. Primary/secondary
We know the shape of a cone from its concept, but we don't know its colour
                        Full Idea: The shape of a cone we can form for ourselves in intuition, unassisted by any experience, according to its concept alone, but the colour of this cone must be previously given in some experience or other.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B743/A715)
                        A reaction: Coffa says this gives a 'transcendental twist' to the primary/secondary distinction. The distinction doesn't seem to help much, since you clearly don't know the shape of a pebble from its concept. Is the angle of the cone part of its concept?
12. Knowledge Sources / B. Perception / 2. Qualities in Perception / d. Secondary qualities
Colours and tastes are not qualities of things, but alterations of the subject
                        Full Idea: Things like colors, taste etc. are correctly considered not as qualities of things but as mere alterations of our subject, which can even be different in different people.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B045/A29)
                        A reaction: This acceptance of the category of 'secondary' qualities shows that Kant is not totally daft about reality. He 'considers them as' alterations in the subject, but how does he view primary qualities? Not, I think, as features of the noumenon.
12. Knowledge Sources / B. Perception / 5. Interpretation
Kant says the cognitive and sensory elements in experience can't be separated
                        Full Idea: Kant maintains that it is impossible to draw a suitable distinction between the cognitive and sensory 'elements' in sensory experience.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Jonathan Dancy - Intro to Contemporary Epistemology 8.4
12. Knowledge Sources / B. Perception / 6. Inference in Perception
Appearances have a 'form', which indicates a relational order
                        Full Idea: That which allows the manifold of appearance to be intuited as ordered in certain relations I call the 'form' of appearance.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B034/A20)
                        A reaction: An important idea, which figures prominently in Wittgenstein's Tractatus. Presumably the noumenon is responsible for generating the form in the appearances, and we infer the order of the world thereby (though we can't prove it).
12. Knowledge Sources / C. Rationalism / 1. Rationalism
We cannot represent objects unless we combine concepts with intuitions
                        Full Idea: Understanding and sensibility can determine an object only in combination; if we separate them, then we have intuitions without concepts, or concepts without intuitions, but in either case representations that we cannot relate to any determinate objects.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B314/A258)
                        A reaction: Although Kant seems to be rejecting the rationalist v empiricist debate, I take this to be evidence that Kant was a rationalist, because he thinks understanding cannot arise just from sensibility.
12. Knowledge Sources / D. Empiricism / 2. Associationism
I exist just as an intelligence aware of its faculty for combination
                        Full Idea: I exist as an intelligence that is merely conscious of its faculty for combination.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B158)
                        A reaction: [plucked from a complex context!] This thought seems to have its origins in Hume's account of associations, and is a fairly accurate piece of introspection, I would say. I could think of my Self simply as the thing which unites some diverse experiences.
Associations and causes cannot explain content, which needs norms of judgement
                        Full Idea: Kant said the representational content of thought could not be explained by patterns of association or by naturalistically understood causal patterns; the cognitive content of thought is constituted entirely by the norms governing judgemental synthesis.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Terry Pinkard - German Philosophy 1760-1860 01
                        A reaction: I'd be inclined to say that it needs a concept of truth, rather than Kant's tangle of norms and categories. Maybe the content is there before the associations get to work.
12. Knowledge Sources / D. Empiricism / 4. Pro-Empiricism
For Kant, our conceptual scheme is disastrous when it reaches beyond experience
                        Full Idea: For Kant, the conceptual apparatus that structures our experience for us will inevitably lead to intellectual disasters when it is applied to matters completely beyond experience.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Robert Fogelin - Walking the Tightrope of Reason Ch.3
                        A reaction: This is the empiricist side of Kant, influenced by Hume. I don't agree with Kant on this. I just think that speculation and abstract theory are much more difficult and error-prone than science, because you can't keep checking against raw facts.
12. Knowledge Sources / D. Empiricism / 5. Empiricism Critique
Understanding has no intuitions, and senses no thought, so knowledge needs their unity
                        Full Idea: The understanding is not capable of intuiting anything, and the senses are not capable of thinking anything. Only from their unification can cognition arise.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B075/A51)
                        A reaction: At first glance this seems to settle the rationalist-empiricist debate at a stroke, by rejecting the rationalist dream of knowledge arising from pure intuitions, and the empiricist dream of knowledge from pure sensation. It can't be that simple, though…
Sensations are a posteriori, but that they come in degrees is known a priori
                        Full Idea: All sensations are given only a posteriori, but their property of have a degree can be cognised only a priori.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B218/A176)
                        A reaction: Study the context to be fair to Kant, but this seems very unconvincing. If we were constructed in some more digital way, our sensations might be binary, so their 'degree' can hardly be a necessity.
12. Knowledge Sources / E. Direct Knowledge / 2. Intuition
Kantian intuitions are of particulars, and they give immediate knowledge
                        Full Idea: For Kant, intuitions are singular, in the sense that they are modes of representing individual objects, and are needed for numbers and geometric figures; ..they also yield immediate knowledge, and are tied to sense perceptions.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Stewart Shapiro - Thinking About Mathematics 4.2
                        A reaction: The ordinary usage of the word 'intuition' agrees on the immediate knowledge produced, but not on the 'singular' aspect of it, so that is the respect in which Kant's use is a term of art. Why have a special faculty for singular apprehensions?
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / f. Foundationalism critique
A sufficient but general sign of truth cannot possibly be provided
                        Full Idea: It is clear that a sufficient and yet at the same time general sign of truth cannot possibly be provided.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B083/A59)
                        A reaction: In relation to the quest of Sextus Empiricus to find the 'criterion' of knowledge, this makes Kant a sceptic. It certainly seems to rule out any foundationalist view of knowledge. (Clearly Kant believes that an account of knowledge is possible).
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
Kant says knowledge is when our representations sufficiently conform to our concepts
                        Full Idea: Kant, in his epistemology, turns the issue of scepticism around by acknowledging that, although we can never know things-in-themselves, the objects of our representations conform to the concepts we have of them in a manner sufficient for knowledge.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Simon Critchley - Continental Philosophy - V. Short Intro Ch.2
                        A reaction: This seems to invite the problem of a brain-in-a-vat, which is fed absurd representations, and set up with a bunch of silly concepts that conform to the representations.
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
Kant thought he had refuted scepticism, but his critics say he is a sceptic, for rejecting reality
                        Full Idea: Kant believed he had given a decisive answer to traditional scepticism, since we can no longer be mistaken about objects, but his critics say he is a sceptic, because he relinquishes our grasp of independent things.
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Paul O'Grady - Relativism Ch.3
                        A reaction: A simple issue to raise about the man, my first reaction being that he is a sceptic. He says the 'noumenon' (true reality) is unknowable, but I say we can meaningfully speculate and theorise about it.
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
Scepticism is absurd in maths, where there are no hidden false assertions
                        Full Idea: The sceptical method would be absurd in mathematics, because nowhere in mathematics do false assertions disguise themselves and make themselves invisible.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B452/A424)
                        A reaction: An interesting observation. The implication I take here is that scepticism in the realm of sensation is justified, precisely because errors and illusion do occur.
Scepticism is the euthanasia of pure reason
                        Full Idea: Reason is tempted to surrender itself to a sceptical hopelessness, which might also be called the euthanasia of pure reason.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B434/A407)
                        A reaction: Colin McGinn's 'mysterian' pessimism about the mind-body problem comes to mind!
13. Knowledge Criteria / E. Relativism / 1. Relativism
For Kant, experience is relative to a scheme, but there are no further possible schemes
                        Full Idea: For Kant, experience is relativised to a categorial framework, but there is no further relativisation, at least in any deep respect, to a plurality of possible conceptual schemes.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Robert Fogelin - Walking the Tightrope of Reason Ch.3
                        A reaction: This point is enlarged nicely by Davidson, in his view that we could make no sense of a different 'conceptual scheme' (Idea 6398). Kant's resistance to speculation prevents him imagining how it might be to be an angel, or an alien, or a Hopi.
14. Science / A. Basis of Science / 6. Falsification
If a proposition implies any false consequences, then it is false
                        Full Idea: If only a single false consequence can be derived from a proposition, then this proposition is false.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B819/A791)
                        A reaction: Seems right. Of course, it might imply entirely true consequences, and still be false. This idea has to be one of the foundations (sic) of coherentism about truth and justification.
15. Nature of Minds / A. Nature of Mind / 3. Mental Causation
Freedom and natural necessity do not contradict, as they relate to different conditions
                        Full Idea: Are freedom and natural necessity contradictory in an action? We have shown that freedom can relate to conditions of a kind entirely different from those in natural necessity, so each is independent of the other.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B585/A557)
                        A reaction: I'm not sure I understand this, but I suspect that it means that a serious case of kleptomania while never provide even the hint of an excuse for a minor theft. We're all free, and that's that. I am dubious.
15. Nature of Minds / B. Features of Minds / 1. Consciousness / f. Higher-order thought
Kant thought that consciousness depends on self-consciousness ('apperception')
                        Full Idea: Kant thought that consciousness in general depends for its possibility on self-consciousness (or, as he called it, 'apperception').
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Tim Crane - Elements of Mind 3.21
                        A reaction: What would Kant have made of Darwin? Consciousness looks very useful in small dim animals for registering survival information.
15. Nature of Minds / C. Capacities of Minds / 1. Faculties
Kant's only answer as to how synthetic a priori judgements are possible was that we have a 'faculty'!
                        Full Idea: Kant asked himself: how are synthetic judgements a priori possible? And what, really, did he answer? By means of a faculty!
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Friedrich Nietzsche - Beyond Good and Evil §011
Judgements which are essentially and strictly universal reveal our faculty of a priori cognition
                        Full Idea: Empirical universality is an increase in validity from most cases to all cases (e.g. all bodies are heavy), whereas strict universality belongs to a judgement essentially; this points to a special faculty of a priori cognition for it.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B004)
                        A reaction: I would say that 'strict' universality arises not directly from some faculty, but from increasing degrees of refinement by abstraction. It is merely the iterations of a lower faculty, not the pure deliverances of a higher one.
Reason has logical and transcendental faculties
                        Full Idea: Reason has logical and transcendental faculties.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B355/A299)
                        A reaction: The notion of a transcendental faculty is not entirely clear (despite all Kant's efforts), but it is certainly vital to grasp that rationality extends way beyond logic. The clearest example is induction, which is rational, despite its shortage of logic.
15. Nature of Minds / C. Capacities of Minds / 2. Imagination
We are seldom aware of imagination, but we would have no cognition at all without it
                        Full Idea: Imagination - a blind though indispensable function of the soul, without which we would have no cognition at all, but of which we are seldom even conscious.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B103/A78)
                        A reaction: I'm not sure why he calls it 'blind', since I can very deliberately control imagination. Neverthless, I applaud his recognition of imagination's central importance, even (I take it) in the simple act of looking out of the window.
16. Persons / B. Nature of the Self / 3. Self as Non-physical
I can express the motion of my body in a single point, but that doesn't mean it is a simple substance
                        Full Idea: I can express the motion of my body through the motion of a point, since its volume is not relevant, but I could not infer from this that if I know nothing except the moving force of a body, that then the body can be conceived as a simple substance.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B812/A784)
                        A reaction: A nice analogy. The centre of gravity of a body is an abstraction, and people (such as Cartesians) who represent personal identity as being atomic seem to be discussing an abstraction rather than the real thing. My personal self is a bit of a mess.
16. Persons / B. Nature of the Self / 4. Presupposition of Self
To some extent we must view ourselves as noumena
                        Full Idea: To some extent we must view ourselves as noumena.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Christine M. Korsgaard - Intro to 'Creating the Kingdom of Ends' xi
                        A reaction: An illuminating idea. We are inclined to thing of reality as 'out there', and hence potentially unreachable, but we actually experience 'being reality' directly in ourselves. Is this the germ of the whole of continental philosophy?
Representation would be impossible without the 'I think' that accompanies it
                        Full Idea: The 'I thinks' must be able to accompany all my representations; for otherwise something would be represented in me that could not be thought at all, which is as much as to say that representation would be impossible, or would be nothing to me.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B132)
                        A reaction: This is evidently a flat rejection of Hume's claim that he is a bundle of experiences with no self to co-ordinate them. Presumably this should apply to animals too, if they 'represent' their world (and how could they not?).
16. Persons / B. Nature of the Self / 7. Self and Body / a. Self needs body
We need an account of the self based on rational principles, to avoid materialism
                        Full Idea: Why do we have need of a doctrine of the soul grounded merely on pure rational principles? Without doubt chiefly with the intent of securing our thinking Self from the danger of materialism.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B406-/A383)
                        A reaction: And why is materialism a 'danger'? Only, I think, because it would make immortality impossible. Huge chunks of Enlightenment philosophy are the last vestiges of the religious view of reality. I think we can base morality on a material self.
16. Persons / C. Self-Awareness / 2. Knowing the Self
Self-knowledge can only be inner sensation, and thus appearance
                        Full Idea: We know even ourselves only through inner sense, thus as appearance.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B334/A278)
                        A reaction: I'm not sure what it means to say that 'inner sense' is merely 'appearance'. Surely appearance is reality, within a mind? To want to see the real 'me' behind the world of inner appearances is a very odd kind of dream.
16. Persons / C. Self-Awareness / 3. Limits of Introspection
I have no cognition of myself as I am, but only as I appear to myself
                        Full Idea: I have no cognition of myself as I am, but only as I appear to myself.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B158)
                        A reaction: The key thought of the 'transcendental ego', showing a clear difference from Descartes, who thinks he directly knows himself (Idea 1401). He disagrees with Hume (Idea 1317) when he says there is an appearance. What could the true ego be like?
16. Persons / D. Continuity of the Self / 2. Mental Continuity / c. Inadequacy of mental continuity
I can only determine my existence in time via external things
                        Full Idea: The determination of my existence in time is possible only by means of the existence of actual things that I perceive outside of myself.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B275)
                        A reaction: This may be the germ of Hegel's much more social view of the self. Kant is only concerned with the question of identity across time.
As balls communicate motion, so substances could communicate consciousness, but not retain identity
                        Full Idea: A series of elastic balls can successively communicate motion to one another. If mental substances communicated consciousness in this way, the last substance would be conscious of the previous states, but would not be the very same person.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B406-/A364)
                        A reaction: A nice attack on John Locke's proposal, though Locke was aware of this scenario, and claimed the identity followed the consciousness. Clearly, though, if I share my thoughts with you, you don't instantly become me!
16. Persons / D. Continuity of the Self / 3. Reference of 'I'
For Kant the self is a purely formal idea, not a substance
                        Full Idea: Kant insists that the 'I' of consciousness is purely formal, and does not carry with it any positive conception of the self as substance.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781], B406-/A398-9) by Michael Lockwood - Mind, Brain and the Quantum p.169
                        A reaction: We might agree that a self does not involve any awareness of the substance of which it is constituted, but it is hard to see why we might get so worked up about the past, present and future of something which is 'purely formal'.
16. Persons / D. Continuity of the Self / 7. Self and Thinking
Mental representations would not be mine if they did not belong to a unified self-consciousness
                        Full Idea: The manifold representations that are given in a certain intuition would not all together be my representations if they did not all together belong to a self-consciousness.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B132)
                        A reaction: Kant's 'transcendental ego' may only be a posh way of restating the Cartesian Cogito. Descartes was keen to assert not only that there must be a thinker, but also that its essence was to be unified in a manner beyond the physical (Ideas 2303 and 1400).
16. Persons / F. Free Will / 1. Nature of Free Will
We must assume an absolute causal spontaneity beginning from itself
                        Full Idea: It must be assumed that there is an absolute causal spontaneity beginning from itself.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B474/A446)
                        A reaction: Note that this is part of the Antinomies (conflicts) of pure reason. This phrase is a beautiful statement of the dream that is free will.
16. Persons / F. Free Will / 4. For Free Will
We must be free, because we can act against our strongest desires
                        Full Idea: The fact that we are able to act against our strongest desires reveals to us that we are free, and so are members of the intelligible world.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Christine M. Korsgaard - Intro to 'Creating the Kingdom of Ends' Ch.1
                        A reaction: Can he prove that we can act against our strongest desires? If you choose to drown yourself in the sink, you may just be in the grips of a very strong desire to do so, which defeats the normal desire to survive.
If there is a first beginning, there can be other sequences initiated from nothing
                        Full Idea: Because we must establish the necessity of a first beginning to make comprehensible an origin of the world, we are permitted to allow that in the course of the world different series may begin on their own as far as their causality is concerned.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B478/A450)
                        A reaction: This reinforces my firmly held view, that human free will is a bogus concept, which was invented in order place God above nature, and then ascribed to human beings because no other explanation of moral responsibility could be found.
17. Mind and Body / A. Mind-Body Dualism / 1. Dualism
Soul and body connect physically, or by harmony, or by assistance
                        Full Idea: The three usual systems (really the only possible ones) for the community between soul and body are physical influence, preestablished harmony, and supernatural assistance.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B406-/A390)
                        A reaction: This summarises the views of Descartes, Leibniz and Malebranche. Kant is not committing himself to dualism here. He didn't think of epiphenomenalism, or property dualism. And the 'community' could just be a coincidence…
17. Mind and Body / A. Mind-Body Dualism / 8. Dualism of Mind Critique
Our concept of an incorporeal nature is merely negative
                        Full Idea: Our concept of an incorporeal nature is merely negative.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B827/A799)
                        A reaction: This nicely pinpoints a well-known problem with the dualist theory of mind.
Neither materialism nor spiritualism can reveal the separate existence of the soul
                        Full Idea: If materialism will not explain my existence, then spiritualism is just as unsatisfactory, and the conclusion is that in no way can we cognise anything about the constitution of our soul that concerns its possible separate existence.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B420)
                        A reaction: This is Kant's refusal to deal with the mind-body relation, because the mind and its identity have a 'transcendental' status. I.e. they are unavoidable presuppositions about which nothing can be asked. I don't think I agree with him. I'm a materialist.
18. Thought / A. Modes of Thought / 1. Thought
A pure concept of the understanding can never become an image
                        Full Idea: The schema of a pure concept of the understanding is something that can never be brought to an image at all.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B181/A142)
                        A reaction: Interesting. He is thinking of triangles, for example. The emphasis is on 'pure', and this is a nice defence of the notion of 'pure reason'. Obviously you wouldn't understand a triangle if you were incapable of imagining one.
18. Thought / A. Modes of Thought / 5. Rationality / a. Rationality
Kantian 'intuition' is the bridge between pure reason and its application to sense experiences
                        Full Idea: In Kant's technical sense, 'intuition' is the bridge between sense experience and pure reasoning, making it possible for us to apply our reasoning to the physical world around us.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Michčle Friend - Introducing the Philosophy of Mathematics 3.3
                        A reaction: Although this concept invites Ockham's Razor, I like it, since it focuses on the mystery of how reasoning can have application. It is the bridge between the analytic and the synthetic, between the a priori and the empirical. It unites thought.
18. Thought / B. Mechanics of Thought / 2. Categories of Understanding
Kant deduced the categories from our judgements, and then as preconditions of experience
                        Full Idea: Kant provided a 'metaphysical deduction' of the categories by deriving them from the fundamental forms of judgement. He also gave a 'transcendental deduction' of the categories ...as the indispensable conditions of our knowledge and experience of objects
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Stephen Houlgate - An Introduction to Hegel 02 'From indeterminate'
                        A reaction: I'm suspicious of the second method, because it seems that all you can do is make up an explanation of experience, with very little to go on, because it is hidden. Analysing the way we make judgements is more interesting.
Kant says we can describe the categories of thought, but Hegel claims to deduce them
                        Full Idea: Kant maintains that we can only describe the a priori forms of knowledge (space and time, and the twelve categories), whereas Hegel insists that it is possible to deduce them.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Quentin Meillassoux - After Finitude; the necessity of contingency 2
                        A reaction: I've some sympathy with Kant here. There is a sort of introspective philosophical psychology which seems to be possible, independently from empirical psychology.
Categories are concepts that prescribe laws a priori to appearances
                        Full Idea: Categories are concepts that prescribe laws a priori to appearances.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B163)
                        A reaction: The intriguing word here is 'laws'. Might it be possible to create a new category of the understanding, by taking drugs, or by spectacularly imaginative thought? It all sounds a bit conservative (as Nietzsche suggested - Idea 2859).
Four groups of categories of concept: Quantity, Quality, Relation and Modality
                        Full Idea: Four groups of categories: Quantity (unity,plurality,totality), Quality (reality,negation,limitation), Relation (inherence/subsistence, causality/dependence,community), and Modality (possible/impossible,exist/non-exist,necessary/contingent).
                        From: Immanuel Kant (Critique of Pure Reason [1781], B106/A80)
                        A reaction: I can't challenge this claim, but Kant himself invites us to compare his scheme with that of Aristotle. See Idea 3311 for a summary. I prefer the way Aristotelian categories 'peter out', rather than being clear and determinate. Hegel had a shot too.
The categories are objectively valid, because they make experience possible
                        Full Idea: The objective validity of the categories, as a priori concepts, rests on the fact that through them alone is experience possible.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B126/A93)
                        A reaction: The human mind is clearly a sort of database, with a flexible structure, but the grounding of it has to be innate, and a priori additions are made at an early stage. I take the categories to be the basic folders of the database, but they may be cultural.
18. Thought / D. Concepts / 1. Concepts / a. Nature of concepts
Thoughts without content are empty, intuitions without concepts are blind
                        Full Idea: Without sensibility no object would be given to us, and without understanding none would be thought. Thoughts without content are empty, intuitions without concepts are blind.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B075/A51)
                        A reaction: A famous assertion, which requires quite a lot of deconstruction. See MacDowell 1994 for example. Whatever the solution, it had better allow animals to cope with their world, because that's what they do.
Either experience creates concepts, or concepts make experience possible
                        Full Idea: There are only two ways in which a necessary agreement of experience with the concepts of its objects can be thought: either the experience makes these concepts possible or these concepts make the experience possible.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B166)
                        A reaction: A nice clear statement of the big question about concepts. The extremes seem to be the 'tabula rasa' versus Fodor's strong 'nativism' (that most concepts are innate). Personally I want to be as empiricist as possible. Kant needs a theory of their origin.
Reason generates no concepts, but frees them from their link to experience in the understanding
                        Full Idea: Only from the understanding can pure concepts arise, and reason cannot generate any concept at all, but can only free a concept of the understanding from the unavoidable limitations of possible experience, and extend it beyond empirical boundaries.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B435/A409)
                        A reaction: Presumably Descartes' 'natural light' should cover the understanding as much as the reason. This quotation brings out the empirical aspect of Kant's thought. It suggests that analysis is the main function of reason.
18. Thought / D. Concepts / 1. Concepts / c. Concepts in psychology
Concepts are rules for combining representations
                        Full Idea: For Kant, concepts should be thought of as rules for the combination of representations.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Terry Pinkard - German Philosophy 1760-1860 01
                        A reaction: Kant seems to have thought that they are rules we decree for ourselves (like the categorical imperative). So think of private languages, and you get Hegel's much more social view of concepts (I think).
All human cognition is through concepts
                        Full Idea: The cognition of every, at least human, understanding is a cognition through concepts. ...A concept is a unity of the act of bringing various representations under one common representation.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B093/A68)
                        A reaction: This puts concepts right at the heart of human understanding, as the building blocks for propositions and beliefs. Do gods and dogs use concepts? If artificial intelligence cannot program concepts, is it defeated? Are there non-conscious concepts? …
18. Thought / D. Concepts / 4. Structure of Concepts / b. Analysis of concepts
Kant implies that concepts have analysable parts
                        Full Idea: Kant's definition of 'analyticity' presupposes that concepts have parts (at least metaphorically).
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Stewart Shapiro - Thinking About Mathematics
                        A reaction: The concept of a 'bachelor' seem undeniably to have parts. Others, however, seem to lack components, such as 'one', 'red', 'true'. Hence concepts must fall into two groups: primitive and composite. In any language. In any proposition.
19. Language / E. Analyticity / 1. Analytic Propositions
Non-subject/predicate tautologies won't fit Kant's definition of analyticity
                        Full Idea: Not every proposition has a subject-predicate form, and so by contemporary lights Kant's definition of analyticity [predicate contained in subject] is unnatural and stifling. What of 'If it is raining now, then either it is raining or it is snowing'?
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Stewart Shapiro - Thinking About Mathematics 4.2
                        A reaction: Only a logician would want to assert something so pointless. Kant gives a pretty good account of normal language tautologies. Still, you can't deny the point.
How can bachelor 'contain' unmarried man? Are all analytic truths in subject-predicate form?
                        Full Idea: There are two problems with Kant's characterisation of analytic truths (as having 'the predicate contained within the subject'): what exactly does it mean to say that bachelor "contains" unmarried man?, and it is limited to subject-predicate sentences.
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Alexander Miller - Philosophy of Language 4.2
                        A reaction: He picks these objections up from Quine. I always have reservations about Quine's supposed demolition of analytic truths, but there is no denying that these are two excellent problems which need addressing.
If the predicate is contained in the subject of a judgement, it is analytic; otherwise synthetic
                        Full Idea: In judgements, the relation of subject to predicate is possible in two ways. Either the predicate B belongs to the subject A as (covertly) contained in this concept A; or B lies entirely outside A. The first I call analytic, the second synthetic.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B010/A6)
                        A reaction: Rey says this is the first introduction of the analytic/synthetic disctinction. Modern philosophers seem to reject this definition, mainly because they are suspicious of the vague word 'contained'. Depends what a concept is.
Analytic judgements clarify, by analysing the subject into its component predicates
                        Full Idea: One could call an analytic judgement one of clarification ...since the predicate does not add anything to the concept of the subject, but only breaks it up by means of analysis into its component concepts.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B011/A7)
                        A reaction: This is a very illuminating view of the concept, which seems to have fallen into disrepute. If we ask what predicates are contained in 'tree', we may quickly have to embrace essentialism, to decide which predicates matter.
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / a. Preconditions for ethics
Without God, creation and free will, morality would be empty
                        Full Idea: If there is no original being different from the world, if the world is without a beginning and without an author, if our will is not free and our soul is of the same corruptibility as matter, then moral ideas and principles lose all validity.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B496/A468)
                        A reaction: Atheism or determinism might lead to the collapse of your morality, if you had an amazingly inflated idea of the cosmic importance of human beings behaving well. My view is that morality just concerns important decisions made by healthy persons.
22. Metaethics / B. Value / 1. Nature of Value / b. Fact and value
We cannot derive moral laws from experience, as it is the mother of illusion
                        Full Idea: With respect to moral laws, experience is (alas!) the mother of illusion, and it is most reprehensible to derive the laws concerning what I ought to do from what is done, or to want to limit it to that.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B375/A319)
                        A reaction: Kant agrees with Hume, and turns to a non-naturalistic and cognitivist explanation, whereas Hume turns to a non-cognitivist naturalistic one (based on human feelings). Aristotle's view is somewhat based on the experience of human nature.
22. Metaethics / B. Value / 2. Values / a. Normativity
We only understand what exists, and can find no sign of what ought to be in nature
                        Full Idea: In nature the understanding cognizes only what exists, or has been, or will be. It is impossible that something ought to be other that what it in fact is. ...We cannot ask what ought to happen in nature, any more than what properties a circle should have.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B575/A547)
                        A reaction: This seems to be the first clear recognition of what we now call 'normativity', which seems like a misfit in naturalistic views. Davidson derives a sort of mental dualism from it. Note that powers and dispositions can also not be directly cognised.
23. Ethics / D. Deontological Ethics / 6. Motivation for Duty
Moral blame is based on reason, since a reason is a cause which should have been followed
                        Full Idea: Moral blame is grounded in the law of reason, which regards reason as a cause that, regardless of all the empirical conditions, could have and ought to have determined the conduct of the person to be other than it is.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B583/A555)
                        A reaction: This appears to be a description of akrasia, in which case it is hard to see how a reason is a cause if it doesn't actually produce the result it judges to be right. Kant is an intellectualist about morality, but not about practical reason, it seems.
Moral laws are commands, which must involve promises and threats, which only God could provide
                        Full Idea: Everyone regards moral laws as commands, which they could not be if they did not connect consequences with their rule a priori, and thus carry with them promises and threats, which must lie in a necessary being as the highest good.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B839/A811)
                        A reaction: This reveals the thinking of Kant's moral argument for God rather more nakedly than elsewhere.
23. Ethics / F. Existentialism / 5. Existence-Essence
For Kant, essence is mental and a mere idea, and existence is the senses and mere appearance
                        Full Idea: Kant's philosophy is the contradiction of essence and existence; essence lies in the mind and existence in the senses; existence without essence is mere appearance, and essence without existence is mere idea.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Ludwig Feuerbach - Principles of Philosophy of the Future §22
                        A reaction: The Sartrean challenge is that existence without essence is not mere appearance, but is the central feature of reality as it actually is. One might even flirt with the slogan 'existence is essence'.
24. Political Theory / D. Ideologies / 6. Liberalism / d. Liberal freedom
An obvious idea is a constitution based on maximum mutual freedom for citizens
                        Full Idea: A constitution providing for the greatest human freedom according to laws that permit the freedom of each to exist together with that of others is at least a necessary idea.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B373/A316)
                        A reaction: The basis of Mill's 'On Liberty'. Given that he claims it to be a necessary idea, it is strikingly characteristic of the Enlightenment, and not the sort of thing that occurred to people in 1320. Individual freedom acquired a value. John Lilburne?
25. Social Practice / A. Freedoms / 6. Political freedom
The existence of reason depends on the freedom of citizens to agree, doubt and veto ideas
                        Full Idea: The very existence of reason depends on freedom, which has no dictatorial authority, but whose claim is never anything more than the agreement of free citizens, each of whom must be able to express reservations, indeed even veto, without holding back.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B766/A738)
                        A reaction: I think the biggest conflict within modern societies (as opposed to currently existing medieval ones) is between the freedom that is required for a rational society, and the restraint which is required for a virtuous society. What has highest value?
26. Natural Theory / A. Speculations on Nature / 1. Nature
Kant's nature is just a system of necessary laws
                        Full Idea: In the first Critique, nature is just a system of necessary laws.
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Andrew Bowie - German Philosophy: a very short introduction 1
                        A reaction: This seems to have provoked rebellion in Schiller and the early Romantics, and Kant tried to add teleology to his picture of nature. Leibniz saw nature as dimly alive, and Schiller focused on organisms. Biology is not very lawlike.
Kant identifies nature with the scientific picture of it as the realm of law
                        Full Idea: For Kant the idea of nature is the idea of the realm of law, the idea that came into focus with the rise of modern science.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by John McDowell - Mind and World V.4
                        A reaction: Any doubts about the existence of laws of nature (e.g. Ideas 5470, 6781, 5474) would pull the mat out from under this view. I am inclined to view nature as the realm of natural kinds, which give rise to the regularities we call 'laws'.
26. Natural Theory / A. Speculations on Nature / 2. Natural Purpose / b. Limited purposes
Reason must assume as necessary that everything in a living organism has a proportionate purpose
                        Full Idea: Regarding the nature of living beings in this world, reason must assume as a necessary principle that no organ, no faculty, nothing superfluous, or disproportionate to its use, hence nothing purposeless, is to be met with.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B425)
                        A reaction: Extraordinary to treat this as an a priori truth! In fact Darwin seems to have discovered that most organs have a purpose, but sometimes they have become redundant, and certainly they can be disproportionate. Did Kant really need that massive intellect?
26. Natural Theory / A. Speculations on Nature / 7. Later Matter Theories / c. Matter as extension
Extension and impenetrability together make the concept of matter
                        Full Idea: Extension and impenetrability together constitute the concept of matter.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B646/A618)
                        A reaction: Descartes had settled for extension alone. Kant's simple claim is probably now just a historical footnote, as we would now turn to physicists to define matter. Extension might survive, but impenetrability is not a key notion in quantum mechanics.
26. Natural Theory / C. Causation / 8. Particular Causation / b. Causal relata
A ball denting a pillow seems like simultaneous cause and effect, though time identifies which is cause
                        Full Idea: If I consider a ball that lies on a stuffed pillow and makes a dent in it as a cause, it is simultaneous with its effect. Yet I distinguish the two by means of the temporal relation of the dynamical connection.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B248/A203)
                        A reaction: Mumford and Lill Anjum use this example to defend simultaneous cause and effect, whereas Kant seems to be in the grip of an a priori assumption that cause must come first. At the micro level Kant may be right. Two books lean on one another?
26. Natural Theory / C. Causation / 9. General Causation / a. Constant conjunction
Appearances give rules of what usually happens, but cause involves necessity
                        Full Idea: The concept of cause always requires that something A be of such a kind that something else B follows from it necessarily and in accordance with an absolutely universal rule. Appearances may give a rule that something usually happens, but not necessarily.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B124/A91)
                        A reaction: I must side with Hume when it is put like this. As all empiricists are keen to tell us, a strong feeling of necessity is not enough to guarantee it. Has Kant confused 'natural' and 'metaphysical' necessity? We can't learn natural necessity a priori.
26. Natural Theory / C. Causation / 9. General Causation / b. Nomological causation
The concept of causality entails laws; random causality is a contradiction
                        Full Idea: For Kant, the will is a causality, and the concept of a causality entails laws; a causality which functions randomly is a contradiction.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Christine M. Korsgaard - Intro to 'Creating the Kingdom of Ends' Ch.1
                        A reaction: This seems to be a rather Humean view, which may be confusing the epistemology (of how we might detect causes) from the ontology (of what causation is). Where is the logical contradiction in random unpredictable causes?
We judge causation by relating events together by some law of nature
                        Full Idea: Kant says that we can judge one event to cause another if we can relate the two events to one another by some law of nature.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Edwin D. Mares - A Priori 07.3
                        A reaction: I take this to have got things exactly the wrong way round, since it leaves no notion of the foundations of the laws being used to do the explaining. The laws have to be primitive or supernatural.
Experience is only possible because we subject appearances to causal laws
                        Full Idea: It is only because we subject the sequence of appearances and thus all alteration to the law of causality that experience itself is possible.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B234/A189)
                        A reaction: Remarks like this make me sympathise with Hume. Kant puts it too strongly. It strikes me as theoretically possible to 'experience' a sequence with no thought of causality.
26. Natural Theory / C. Causation / 9. General Causation / d. Causal necessity
Causation obviously involves necessity, so it cannot just be frequent association
                        Full Idea: The very concept of a cause obviously contains the concept of a necessity of connection with an effect and a strict universality of rule, which would be entirely lost if one sought, as Hume did, to derive it from a frequent association.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B005)
                        A reaction: It is not clear (in the next paragraphs) whether Kant is saying causation is necessary because it is knowable a priori, or knowable a priori because it is necessary. I am quite sure that Hume cannot be dismissed as glibly as this.
26. Natural Theory / D. Laws of Nature / 8. Scientific Essentialism / b. Scientific necessity
For Kant the laws must be necessary, because contingency would destroy representation
                        Full Idea: Kant considers the hypothesis of the contingency of the laws of nature to be refuted by the mere fact of representation. ...If representation were no longer structured by causality, it would no longer structure any aspect of the phenomenon at all.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Quentin Meillassoux - After Finitude; the necessity of contingency 4
                        A reaction: This is based on the belief that a contingent nature would continually change, which Meillassoux denies.
Kant fails to prove the necessity of laws, because his reasoning about chance is over-ambitious
                        Full Idea: Kant's belief in the necessity of laws is revoked as an instance of aleatory reason's unwarranted pretension to reach beyond the limits of experience.
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by Quentin Meillassoux - After Finitude; the necessity of contingency 4
                        A reaction: A glimpse of Meillassoux's master argument. He cites Cantor on the uncountable transfinite, claiming that chance in nature involves the transfinite, but normal reasoning about chances should be restricted to what is countable.
27. Natural Reality / C. Space / 2. Space
We can't learn of space through experience; experience of space needs its representation
                        Full Idea: Thus the representation of space cannot be obtained from the relations of outer appearance through experience, but this outer experience is itself first possible only through this representation.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B038/A23)
                        A reaction: There is an obvious symbiosis between the mental experience of such things as space and the nature of the thing itself, but I don't see what basis Kant can have for his confident distinction.
Space is an a priori necessary basic intuition, as we cannot imagine its absence
                        Full Idea: Space is a necessary representation, a priori, which is the ground of all outer intuitions. One can never represent that there is no space, although one can very well think that there are no objects to be encountered.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B038/A24)
                        A reaction: The proposal that space is a mental intuition rather than a reality strikes me, and most people, as daft, but the observation that we are incapable of imagining the absence of space is striking. It is one of the basics of thought.
27. Natural Reality / D. Time / 1. Nature of Time / a. Absolute time
If space and time exist absolutely, we must assume the existence of two pointless non-entities
                        Full Idea: Those who decide in favour of the subsistence of the absolute reality of space and time must assume two eternal and infinite self-subsisting non-entities which exist (without there being anything real) only to comprehend everything real within themselves.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B056/A39)
                        A reaction: This is an attack on Newton, and modern physics seems (thanks to Einstein) to agree with Kant. However the modern view strikes me as the usual confusion of epistemology and ontology. Physicists report what we can know, without speculation about how it is.
27. Natural Reality / D. Time / 1. Nature of Time / c. Idealist time
One can never imagine appearances without time, so it is given a priori
                        Full Idea: Time is a necessary representation that grounds all intuitions. In regard to appearances in general on cannot remove time, though one can very well take the appearances away from time. Time is therefore given a priori.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B046/A31)
                        A reaction: As with space, the notion that time is a purely a priori intuition, and not a real feature of the 'space-time manifold' strikes me as absurd (though, unlike space, a reductive account of time might be possible), but its absence is indeed unimaginable.
27. Natural Reality / D. Time / 2. Passage of Time / a. Experience of time
That times cannot be simultaneous is synthetic, so it is known by intuition, not analysis
                        Full Idea: The proposition that different times cannot be simultaneous is synthetic, and cannot arise from concepts alone. It is therefore immediately contained in the intuition and representation of time.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B047/A32)
                        A reaction: It seems possible that this proposition is in fact analytic. What would it be like for two times to be simultaneous? If it happened we would not accept it, because it would violate our very concept of an instant in time.
The three modes of time are persistence, succession and simultaneity
                        Full Idea: The three 'modi' of time are persistence, succession and simultaneity.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B219/A177)
                        A reaction: I find such an assertion quite breathtaking in its confidence. How does he know this? It is tempting to try to reduce the three modes down to two or one. See Ideas 2608 and 4230 for McTaggart's reduction to two.
27. Natural Reality / D. Time / 2. Passage of Time / b. Rate of time
If time involved succession, we must think of another time in which succession occurs
                        Full Idea: If one were to ascribe succession to time itself, one would have to think yet another time in which this succession would be possible.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B226/A183)
                        A reaction: The implication of this might be that while we must believe that time exists, we are utterly incapable of imagining its existence.
28. God / A. Divine Nature / 6. Divine Morality / b. Euthyphro question
We don't accept duties as coming from God, but assume they are divine because they are duties
                        Full Idea: So far as practical reason has the right to lead us, we will not hold actions to be obligatory because they are God's commands, but will rather regard them as divine commands because we are internally obligated to them.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B847/A819)
                        A reaction: Thus Kant agrees with Plato in his response to the latter's 'Euthyphro Question' (Ideas 336 and Idea 337).
28. God / B. Proving God / 1. Proof of God
Only three proofs of God: the physico-theological (evidence), the cosmological (existence), the ontological (a priori)
                        Full Idea: There are three proofs of the existence of God: the physico-theological, the cosmological, and the ontological. There are no more of them, and there also cannot be any more.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B619/A591)
                        A reaction: It is hard to deny this, though the 'physico-theological' group may be a sizeable family. The immediate difficulty may be that physical evidence supports something less than God, the cosmological is just speculation, and a priori proofs won't work.
28. God / B. Proving God / 2. Proofs of Reason / b. Ontological Proof critique
Existence is merely derived from the word 'is' (rather than being a predicate)
                        Full Idea: For Kant, existence derives from a true affirmative subject-copula-predicate judgement; existence is not a real predicate, but is merely derivatively implied by the copula ('is').
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by Alex Orenstein - W.V. Quine Ch.2
                        A reaction: This is Kant's understanding of 'existence is not a predicate', prior to the later move of Brentano and Frege, which places existence claims in the quantifier, which is outside the proposition.
Modern logic says (with Kant) that existence is not a predicate, because it has been reclassified as a quantifier
                        Full Idea: Kant's famous critique of the Ontological Argument that existence is not a predicate leaves one perplexed as to what it might be, but modern logic says that existence is a quantifier, not a predicate.
                        From: comment on Immanuel Kant (Critique of Pure Reason [1781]) by José A. Benardete - Metaphysics: the logical approach Ch.10
                        A reaction: See McGinn's criticism of this in Idea 6062.
Kant never denied that 'exist' could be a predicate - only that it didn't enlarge concepts
                        Full Idea: Kant denied that 'exists' was a predicate that enlarged the concept; he never denied that it was a predicate.
                        From: report of Immanuel Kant (Critique of Pure Reason [1781]) by M Fitting/R Mendelsohn - First-Order Modal Logic 8.4
Is "This thing exists" analytic or synthetic?
                        Full Idea: Is the proposition "This or that thing exists" an analytic or a synthetic proposition?
                        From: Immanuel Kant (Critique of Pure Reason [1781], B625/A597)
                        A reaction: Quine's challenge to the analytic/synthetic distinction (e.g. Idea 1626) may spoil this question, but it seems fine ask whether we are talking about words or facts here. Once this question is asked, the Ontological Argument is in trouble.
If 'this exists' is analytic, either the thing is a thought, or you have presupposed its existence
                        Full Idea: If the proposition 'this thing exists' is analytic, ..then either the thought is the thing, or else you have presupposed the existence and then inferred it, which is just a miserable tautology.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B625/A597)
                        A reaction: I love the phrase "miserable tautology"! A possible strategy is to treat God as a self-evident a priori axiom. This would not be a tautology, but it would make evidence irrelevant. This may be the strategy behind Kierkegaard's 'leap of faith'.
If an existential proposition is synthetic, you must be able to cancel its predicate without contradiction
                        Full Idea: If you concede that every existential proposition is synthetic, then how would you assert that the predicate of existence may not be cancelled without contradictions?
                        From: Immanuel Kant (Critique of Pure Reason [1781], B626/A598)
                        A reaction: The point is that the Ontological Argument claims that "God does not exist" is a contradiction. Kant is echoing Hume here. The proposition that 'nothing exists' hardly sounds like a logical impossibility
Being is not a real predicate, that adds something to a concept
                        Full Idea: Being is obviously not a real predicate, i.e. a concept of something that could add to the concept of a thing.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B626/A598)
                        A reaction: Kant's famous slogan against the Ontological Argument. The modern line is that existence is a quantifier, which stands outside a proposition, and says whether it applies to anything. It is worth considering the possibility that Kant is wrong.
You add nothing to the concept of God or coins if you say they exist
                        Full Idea: If I take God together with all his predicates (among which omnipotence belongs), and say 'God is', then I add no new predicate to the concept of God. ..A hundred actual thalers do not contain the least bit more than a hundred possible ones.
                        From: Immanuel Kant (Critique of Pure Reason [1781], B627/A599)
                        A reaction: Norman Malcolm claims that 'necessary existence' adds something to a concept. We can compare a concept with and without contingent existence, but the comparison is void if the existence is necessary. I love Kant's objection, though.
28. God / B. Proving God / 3. Proofs of Evidence / a. Cosmological Proof
If you prove God cosmologically, by a regress in the sequences of causes, you can't abandon causes at the end
                        Full Idea: If one begins the proof cosmologically, by grounding it on the series of appearances and the regress in this series in accordance with empirical causal laws, one cannot later shift from this and go over to something which does not belong to the series
                        From: Immanuel Kant (Critique of Pure Reason [1781], B484/A456)
                        A reaction: Badly expressed, but it is the idea that if you start from 'everything has a cause', you can't use it to prove the existence of an uncaused entity. Better to say: an uncaused entity is the only explanation we can imagine for a causal sequence.