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All the ideas for 'Principles of Philosophy', 'Knowledge by Agreement' and 'Tractatus Logico-Philosophicus'

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151 ideas

1. Philosophy / D. Nature of Philosophy / 1. Philosophy
What we cannot speak about we must pass over in silence [Wittgenstein]
     Full Idea: What we cannot speak about we must pass over in silence.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 7)
     A reaction: This is either a boring truism, or points towards some sort of verificationism (where we can speak meaninglessly). Compare Ideas 7973 and 6870.
1. Philosophy / D. Nature of Philosophy / 2. Invocation to Philosophy
The greatest good for a state is true philosophers [Descartes]
     Full Idea: The greatest good which can exist in a state is to have true philosophers.
     From: René Descartes (Principles of Philosophy [1646], Pref)
     A reaction: …because they understand true reality, especially the Good.
1. Philosophy / D. Nature of Philosophy / 3. Philosophy Defined
I say (contrary to Wittgenstein) that philosophy expresses what we thought we must be silent about [Ansell Pearson on Wittgenstein]
     Full Idea: I recognise the incredible force of Wittgenstein's closing statement in the 'Tractatus', but I hold the opposite view: philosophy exists to give expression to that which we think we can only remain silent about.
     From: comment on Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 7) by Keith Ansell Pearson - Interview with Baggini and Stangroom p.267
     A reaction: A wonderful remark, with which I totally agree. Compare Idea 1596. I think it is just a fact that philosophers are able to articulate a huge number of ideas which other intelligent people find very interesting but on which they are unable to speak.
1. Philosophy / D. Nature of Philosophy / 6. Hopes for Philosophy
If a question can be framed at all, it is also possible to answer it [Wittgenstein]
     Full Idea: If a question can be framed at all, it is also possible to answer it.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.5)
     A reaction: Just the sort of unsubstantiated metaphysical claim that philosophers are always making.
1. Philosophy / D. Nature of Philosophy / 7. Despair over Philosophy
The 'Tractatus' is a masterpiece of anti-philosophy [Badiou on Wittgenstein]
     Full Idea: The 'Tractatus' is without doubt one of the masterpieces of anti-philosophy.
     From: comment on Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Alain Badiou - Mathematics and Philosophy: grand and little p.16
     A reaction: French philosophers do love making wicked remarks like that. It seems that analysis is anti-philosophy, or 'little' philosophy in Badiou's parlance.
This work solves all the main problems, but that has little value [Wittgenstein]
     Full Idea: I believe myself to have found, on all essential points, the final solution of the problems. ….and this work shows how little is achieved when these problems are solved.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], Pref)
     A reaction: This is LW's deep pessimism about the value of philosophy, right from the start. You can only idolise LW if you agree with him on this.
Once you understand my book you will see that it is nonsensical [Wittgenstein]
     Full Idea: Anyone who understands me eventually recognises my propositions as nonsensical, when he has used them - as steps - to climb up beyond them. (He must, so to speak, throw away the ladder after he has climbed up it.)
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.54)
     A reaction: A much discussed passage. It can't possibly say that his book is pointless, because you can't attain this recognition without climbing his ladder. He speaks like an eastern guru. Perhaps Hume should have ended 'so commit my book to the flames'?
1. Philosophy / F. Analytic Philosophy / 5. Linguistic Analysis
The limits of my language means the limits of my world [Wittgenstein]
     Full Idea: The limits of my language means the limits of my world.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.6)
     A reaction: This is dangerous rubbish. For a start, if you accept (as you should) the existence of propositions, our heads are full of unarticulated ones. And truth emerges by degrees from what cannot be articulated.
All complex statements can be resolved into constituents and descriptions [Wittgenstein]
     Full Idea: Every statement about complexes can be resolved into a statement about their constituents and into the propositions that describe the complexes completely.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.0201)
     A reaction: Russell says this embodies Wittgenstein's belief in analysis. Obviously Wittgenstein is making this claim 'in principle', as life is very short, and people are rather dim. I don't know how to begin evaluating such a claim.
Our language is an aspect of biology, and so its inner logic is opaque [Wittgenstein]
     Full Idea: Everyday language is a part of the human organism and is no less complicated than it. It is not humanly possible to gather immediately from it what the logic of language is.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.002)
     A reaction: It is normally assumed that ordinary language philosophy was derived from the later Wittgenstein, but this para in the Tractatus seems to contain the germ of the idea. He is pessimistic about finding logical forms.
Most philosophical questions arise from failing to understand the logic of language [Wittgenstein]
     Full Idea: Most of the propositions and questions of philosophers arise from our failure to understand the logic of our language.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.003)
     A reaction: I'm not sure what the scope of 'logic' is here. I suppose it means everything about language which is expounded in the Tractatus. I assume this includes Plato and Aristotle? I don't think I agree. It's about concepts, not about logic.
1. Philosophy / F. Analytic Philosophy / 7. Limitations of Analysis
This book says we should either say it clearly, or shut up [Wittgenstein]
     Full Idea: The whole sense of the book might be summed up in the following words: what can be said at all can be said clearly, and what we cannot talk about we must pass over in silence.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], Pref)
     A reaction: This also provides the last sentence of his book. I think this is an axiom of modern analytic philosophy. The dream is to clarify everything, and belief that this is possible puts logic centre-stage, as the most precise language available.
1. Philosophy / G. Scientific Philosophy / 3. Scientism
Science is all the true propositions [Wittgenstein]
     Full Idea: The totality of true propositions is the whole of natural science (or the whole corpus of the natural sciences).
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.11)
     A reaction: So if it is true, it is science. What about truths about science? What about true speculations beyond science? What about bad science? What about trivial everyday truths? This is said to be a rare precursor of logical positivism in Tractatus.
2. Reason / B. Laws of Thought / 6. Ockham's Razor
If a sign is useless it is meaningless; that is the point of Ockham's maxim [Wittgenstein]
     Full Idea: If a sign is useless it is meaningless. That is the point of Occam's maxim.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 3.328)
3. Truth / B. Truthmakers / 2. Truthmaker Relation
The best account of truth-making is isomorphism [Wittgenstein, by Mulligan/Simons/Smith]
     Full Idea: The most sophisticated account of truth-making to have appeared to date is the 'isomorphism' theory of the Tractatus.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Mulligan/Simons/Smith - Truth-makers §5
     A reaction: Wittgenstein's theory is clearly closely related to Russell's 'congruence' theory of correspondence of around 1912.
3. Truth / B. Truthmakers / 5. What Makes Truths / c. States of affairs make truths
He says the world is the facts because it is the facts which fix all the truths [Wittgenstein, by Morris,M]
     Full Idea: Wittgenstein is thinking of the world as what makes truths true. …To get all the truths fixed we need more than the things: we need, as it were, the way things are - that is to say, the facts.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 1.12) by Michael Morris - Guidebook to Wittgenstein's Tractatus 1
     A reaction: Morris says this is 'sometimes suggested'. It strikes me as plausible, and makes LW a key source for the modern truthmaker idea. Perhaps in David Lewis's version of it. The facts include the relations and processes of the things.
3. Truth / B. Truthmakers / 11. Truthmaking and Correspondence
All truths have truth-makers, but only atomic truths correspond to them [Wittgenstein, by Rami]
     Full Idea: In 1922 Wittgenstein said that every truth has a truth-maker, but only atomic truths correspond to their truth-makers.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Adolph Rami - Introduction: Truth and Truth-Making note 04
     A reaction: Presumably this is what logical atomism is meant to be (cf Russell). The atomic sentences plug into the world, and the rest are constructions from them, making the latter more remote from the truth-makers.
3. Truth / C. Correspondence Truth / 1. Correspondence Truth
Wittgenstein's picture theory is the best version of the correspondence theory of truth [Read on Wittgenstein]
     Full Idea: Wittgenstein's picture theory is without doubt the best thought-out and developed of all the versions of the correspondence theory of truth.
     From: comment on Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Stephen Read - Thinking About Logic Ch.1
Language is [propositions-elementary propositions-names]; reality is [facts-states of affairs-objects] [Wittgenstein, by Grayling]
     Full Idea: Language consists in propositions, which are made of 'elementary' propositions, which are based ultimately on names. This matches the world of facts, compounded out of 'states of affairs', which are compounded of objects.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by A.C. Grayling - Wittgenstein Ch.2
     A reaction: This is Grayling's summary of the basic idea of the 'Tractatus'. The whole thing seems to be an elaborate version of Russell's 'congruence' account of the correspondence theory of truth. Later Wittgenstein is loss of faith in this theory.
The account of truth in the 'Tractatus' seems a perfect example of the correspondence theory [Wittgenstein, by O'Grady]
     Full Idea: Wittgenstein's account in the 'Tractatus' is often taken as a paradigm instance of a sophisticated correspondence theory of truth.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Paul O'Grady - Relativism Ch.2
     A reaction: This might explain why I am so much more drawn to the 'Tractatus' than to the later relativistic anti-philosophical mind-eliminitavist, meaning-eliminativist Wittgenstein.
Pictures reach out to or feel reality, touching at the edges, correlating in its parts [Wittgenstein]
     Full Idea: A picture attaches to reality by reaching out to it; it is laid against reality like a measure; only the end-points actually touch the object; the pictorial relationship consists of correlations of picture's elements with things, the picture's feelers.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.1511-5)
     A reaction: (somewhat compressed). This is Wittgenstein's so-called 'picture theory' of meaning (replaced later by 'meaning is use'). It is perhaps better seen as an account of the correspondence theory of truth. Compare Russell's 'congruence' view (Idea 5427).
Correspondence could be with other beliefs, rather than external facts [Kusch]
     Full Idea: The correspondence theory of truth does not commit one to the view the reality is mind-independent. There is no reason why the 'facts' that correspond to true beliefs might not themselves be beliefs or ideas.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch.17)
     A reaction: This seems important, as it is very easy to assume that espousal of correspondence necessarily goes with realism about the external world. It is surprising to think that a full-blown Idealist might espouse the correspondence theory.
3. Truth / C. Correspondence Truth / 2. Correspondence to Facts
Proposition elements correlate with objects, but the whole picture does not correspond to a fact [Wittgenstein, by Morris,M]
     Full Idea: Correlation need only be between elements of the picture and things in reality; it is not also required that there be a correspondence between the picture as a whole and a fact in reality - so things can be depicted falsely.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.15121) by Michael Morris - Guidebook to Wittgenstein's Tractatus 3C
     A reaction: To turn his picture theory into a correspondence theory of truth would need a further step, of saying the proposition is true when the two structures coincide. I don't think LW says that.
3. Truth / F. Semantic Truth / 1. Tarski's Truth / a. Tarski's truth definition
Tarskians distinguish truth from falsehood by relations between members of sets [Kusch]
     Full Idea: According to the Tarskians we separate out truths from falsehoods by tracing the relations between members of different sets.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch.16)
5. Theory of Logic / A. Overview of Logic / 1. Overview of Logic
Logic fills the world, to its limits [Wittgenstein]
     Full Idea: Logic pervades the world: the limits of the world are also its limits.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.61)
     A reaction: This is a gospel belief for hardcore analytic philosophy. Hence Williamson writes a book on modal logic as metaphysics.
Logic concerns everything that is subject to law; the rest is accident [Wittgenstein]
     Full Idea: The exploration of logic means the exploration of everything that is subject to law. And outside logic everything is accidental.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.3)
     A reaction: Why should laws be logical? Legislatures can pass whimsical laws. Does he mean that the laws of nature are logically necessary? He can't just mean logical laws.
5. Theory of Logic / A. Overview of Logic / 3. Value of Logic
Wittgenstein is right that logic is just tautologies [Wittgenstein, by Russell]
     Full Idea: I think Wittgenstein is right when he says (in the 'Tractatus') that logic consists wholly of tautologies.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Bertrand Russell - My Philosophical Development Ch.10
     A reaction: Despite Russell's support, I find this hard to accept. While a 'pure' or 'Platonist' logic may be hard to demonstrate or believe, I have a strong gut feeling that logic is more of a natural phenomenon than a human convention.
5. Theory of Logic / A. Overview of Logic / 4. Pure Logic
Logic is a priori because it is impossible to think illogically [Wittgenstein]
     Full Idea: What makes logic a priori is the impossibility of illogical thought.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.4731)
     A reaction: That places the a priori aspect of it in us (in the epistemology), rather than in the necessity of the logic (the ontology), which is as Kripke says it should be.
5. Theory of Logic / B. Logical Consequence / 3. Deductive Consequence |-
If q implies p, that is justified by q and p, not by some 'laws' of inference [Wittgenstein]
     Full Idea: If p follows from q, I can make an inference from q to p, deduce p from q. The nature of the inference can be gathered only from the two propositions. They are the only possible justification of the inference. 'Laws of Inference' would be superfluous.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.132)
     A reaction: That seems to imply that each inference is judged on its particulars. But logic aims to be general. There seem to be 'laws' at a more complex level in the logic.
5. Theory of Logic / C. Ontology of Logic / 1. Ontology of Logic
The propositions of logic are analytic tautologies [Wittgenstein]
     Full Idea: The propositions of logic are tautologies. Therefore the propositions of logic say nothing. (They are the analytic propositions).
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.1)
5. Theory of Logic / C. Ontology of Logic / 2. Platonism in Logic
Wittgenstein convinced Russell that logic is tautologies, not Platonic forms [Wittgenstein, by Monk]
     Full Idea: Russell took a Platonist view of logic, but reading the 'Tractatus' convinced him that logic was purely linguistic, so-called 'logical truths' being nothing more than tautologies.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Ray Monk - Bertrand Russell: Spirit of Solitude Ch.1
     A reaction: If p-and-q and p-or-q are both tautologies, how do you explain the difference between them? The first is an indicative proposition about the actual world, but the second is modal. They are asserting very different things.
5. Theory of Logic / D. Assumptions for Logic / 3. Contradiction
Two colours in the same place is ruled out by the logical structure of colour [Wittgenstein]
     Full Idea: The simultaneous presence of two colours in the same place in the visual field is impossible, in fact logically impossible, since it is ruled out by the logical structure of colour.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.3751)
     A reaction: This sounds the wrong way around. We derive our concept of the logic of colour from experiencing the total incompatibility of two colours in the same location. What if each of our eyes saw a different colour?
5. Theory of Logic / D. Assumptions for Logic / 4. Identity in Logic
The sign of identity is not allowed in 'Tractatus' [Wittgenstein, by Bostock]
     Full Idea: The 'Tractatus' does not allow the introduction of a sign for identity.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by David Bostock - Philosophy of Mathematics 9.B.4
The identity sign is not essential in logical notation, if every sign has a different meaning [Wittgenstein, by Ramsey]
     Full Idea: Wittgenstein discovered that the sign of identity is not a necessary constituent of logical notation, but can be replaced by the convention that different signs must have different meanings.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Frank P. Ramsey - The Foundations of Mathematics p.139
     A reaction: [Ramsey cites p.139 - need to track down the modern reference] Hence in modern logic it is usually necessary to say that we are using 'classical logic with identity', since the use of identity is very convenient, and reasonably harmless (I think).
5. Theory of Logic / E. Structures of Logic / 1. Logical Form
Apparent logical form may not be real logical form [Wittgenstein]
     Full Idea: The apparent logical form of the proposition need not be its real logical form.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.0031), quoted by J. Alberto Coffa - The Semantic Tradition from Kant to Carnap 6 'The incom'
     A reaction: This is one of the key doctrines of modern analytic philosophy.
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / a. Logical connectives
My fundamental idea is that the 'logical constants' do not represent [Wittgenstein]
     Full Idea: My fundamental idea is that the 'logical constants' do not represent; that the logic of facts does not allow of representation.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.0312)
     A reaction: This seems to a firm rebuttal of any sort of platonism about logic, and implies a purely formal account.
5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / c. not
'Not' isn't an object, because not-not-p would then differ from p [Wittgenstein]
     Full Idea: If there were an object called 'not', it would follow that 'not-not-p' would say something different from what 'p' said, just because the one proposition would then be about 'not', and the other would not.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.44)
     A reaction: That is, the first proposition would be about not-p, and the second would be about p. Assuming we can say what such things are 'about'. A rather good argument that the connectives are not entities. P and double-negated P should be indistinguishable.
5. Theory of Logic / E. Structures of Logic / 4. Variables in Logic
'Object' is a pseudo-concept, properly indicated in logic by the variable x [Wittgenstein]
     Full Idea: The variable name ‘x’ is the proper sign of the pseudo-concept object. Wherever the word ‘object’ (‘thing’, ‘entity’, etc.) is rightly used, it is expressed in logical symbolism by the variable name.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.1272)
     A reaction: This seems to be the germ of Quine's famous dictum (Idea 1610). I am not persuaded that because logic must handle an object as a variable, that it follows that we are dealing with a pseudo-concept. Let logic limp behind life.
5. Theory of Logic / F. Referring in Logic / 1. Naming / a. Names
Names are primitive, and cannot be analysed [Wittgenstein]
     Full Idea: A name cannot be dissected any further by means of a definition: it is a primitive sign.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 3.26)
     A reaction: All logicians and analytic philosophers seem to agree on this. He means terms which pick out specific objects.
5. Theory of Logic / F. Referring in Logic / 1. Naming / c. Names as referential
A name is primitive, and its meaning is the object [Wittgenstein]
     Full Idea: A name means an object; an object is its meaning. ...A name cannot be dissected further by means of a definition: it is a primitive sign.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 3.203/3.26)
     A reaction: This is the optimistic view of names, that they are the point at which language plugs into the world (Russell preferred demonstratives for that job). Kripke's baptismal view of names has the same aspiration.
5. Theory of Logic / G. Quantification / 1. Quantification
Wittgenstein tried unsuccessfully to reduce quantifiers to conjunctions and disjunctions [Wittgenstein, by Jacquette]
     Full Idea: Wittgenstein reduces the universal quantifier to conjunctions of singular predications, and the existential quantifier to disjunctions of singular predications. ..This is nowadays understood as a failed effort.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Dale Jacquette - Intro to III: Quantifiers p.143
     A reaction: The problem this meets has something to do with infinite objects. In a domain of three objects it looks like a perfectly plausible strategy. 'All' is all three, and 'Some' is at least one of the three.
5. Theory of Logic / H. Proof Systems / 1. Proof Systems
Logical proof just explicates complicated tautologies [Wittgenstein]
     Full Idea: Proof in logic is merely a mechanical expedient to facilitate recognition of tautologies in complicated cases.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.1262)
5. Theory of Logic / I. Semantics of Logic / 3. Logical Truth
Logical truths are just 'by-products' of the introduction rules for logical constants [Wittgenstein, by Hacking]
     Full Idea: Wittgenstein's by-product theory is that the meanings of the logical constants are conveyed by their introduction rules, and these rules have as a by-product the class of logical truths.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Ian Hacking - What is Logic? §03
     A reaction: I find this approach highly plausible. All the truths about chess openings are just a by-product of the original rules.
5. Theory of Logic / K. Features of Logics / 1. Axiomatisation
Logic doesn't split into primitive and derived propositions; they all have the same status [Wittgenstein]
     Full Idea: All the propositions of logic are of equal status: it is not the case that some of them are essentially primitive propositions and others essentially derived propositions.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.127)
     A reaction: So axioms are conventional. This specifically contradicts the claims of Frege and the earlier Russell. Their view is that logic has an explanatory essence, found in some core axioms or rules or concepts. I agree with them.
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / a. Defining numbers
The concept of number is just what all numbers have in common [Wittgenstein]
     Full Idea: The concept of number is simply what is common to all numbers, the general form of number. The concept of number is the variable number.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.022)
A number is a repeated operation [Wittgenstein]
     Full Idea: A number is the index of an operation.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.021)
     A reaction: Roughly, this means that a number indicates how many times some basic operation has been performed. Bostock 2009:286 expounds the idea.
6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / b. Mathematics is not set theory
The theory of classes is superfluous in mathematics [Wittgenstein]
     Full Idea: The theory of classes is completely superfluous in mathematics. This is connected with the fact that the generality required in mathematics is not accidental generality.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.031)
     A reaction: This fits Russell's no-class theory, which rests everything instead on propositional functions.
6. Mathematics / C. Sources of Mathematics / 6. Logicism / d. Logicism critique
Wittgenstein hated logicism, and described it as a cancerous growth [Wittgenstein, by Monk]
     Full Idea: Wittgenstein didn't just have an arguments against logicism; he hated logicism, and described is as a cancerous growth.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Ray Monk - Interview with Baggini and Stangroom p.12
     A reaction: This appears to have been part of an inexplicable personal antipathy towards Russell. Wittgenstein appears to have developed a dislike of all reductionist ideas in philosophy.
The logic of the world is shown by tautologies in logic, and by equations in mathematics [Wittgenstein]
     Full Idea: The logic of the world, which is shown in tautologies by the propositions of logic, is shown in equations by mathematics.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.22)
     A reaction: White observes that this is Wittgenstein distinguishing logic from mathematics, and thus distancing himself from logicism. But see T 6.2.
7. Existence / A. Nature of Existence / 1. Nature of Existence
The world is facts, not things. Facts determine the world, and the world divides into facts [Wittgenstein]
     Full Idea: The world is the totality of facts, not of things. The world is determined by the facts, and by their being all the facts. The totality of facts determines what is the case, and what is not the case. ..The world divides into facts.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 1 - 1.2)
     A reaction: This is said to be a radical new ontology, because the facts are held to be prior to the things and their properties, which are presumably abstractions from the primitive facts. The modern heir of this is Armstrong's 'states of affairs'.
7. Existence / C. Structure of Existence / 6. Fundamentals / d. Logical atoms
The 'Tractatus' is an extreme example of 'Logical Atomism' [Wittgenstein, by Grayling]
     Full Idea: The 'Tractatus' is an uncompromising, indeed an extreme, example of 'Logical Atomism'
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by A.C. Grayling - Wittgenstein Ch.2
     A reaction: Russell talked about his 'logical atomism' after 1918, but this reminds us that Wittgenstein was fulfilling a task set for him by Russell. Wittgenstein's atoms are names-plus-objects, Russell's are demonstratives-plus-sensedata.
In atomic facts the objects hang together like chain links [Wittgenstein]
     Full Idea: In an atomic fact [Sachverhalt] the objects hang one in another, like the links of a chain
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.03), quoted by Homer - The Iliad
     A reaction: So the world consists of facts, but the facts are composed of objects. The point seems to be that the truths of language refer to the facts, rather than to the objects. Objects 'don't hang' together in the fact of a chance encounter.
The structure of an atomic fact is how its objects combine; this possibility is its form [Wittgenstein]
     Full Idea: The way in which objects hang together in the atomic fact is the structure of the atomic fact. …The form is the possibility of the structure.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.032-3)
     A reaction: I very much like the way LW adds a modal dimension to his ontology. Why doesn't he talk of 'relations', rather than 'hanging together'?
If a proposition is elementary, no other elementary proposition contradicts it [Wittgenstein]
     Full Idea: It is a sign of a proposition's being elementary that there can be no elementary proposition contradicting it.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.211)
     A reaction: It is a hallmark of atomic atoms that they have no relations with other atoms, but are wholly independent. This obviously invites the question of how they are united. Are logical connectives intrinsically relational logical atoms?
Analysis must end in elementary propositions, which are combinations of names [Wittgenstein]
     Full Idea: It is obvious that in the analysis of propositions we must come to elementary propositions, which consist of names in immediate combination.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.221), quoted by Michael Potter - The Rise of Analytic Philosophy 1879-1930 50 'Indep'
     A reaction: Not clear about 'combinations of names'. Does that include predicates? How do you combine two names?
Nothing can be inferred from an elementary proposition [Wittgenstein]
     Full Idea: From an elementary proposition no other can be inferred.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.134)
     A reaction: Russell was not so sure. This is the sort of remark that elicits from me the question that extravagent metaphysics also provokes - 'how on earth does he know what he claims to be true?'.
7. Existence / D. Theories of Reality / 8. Facts / a. Facts
Do his existent facts constitute the world, or determine the world? [Morris,M on Wittgenstein]
     Full Idea: Wittgenstein's writing here is loose, and he seems to be conflating two claims: 1) The totality of existent facts is the world (everything that is the case), and 2) The totality of existent facts determines everything that is the case (the world).
     From: comment on Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.04) by Michael Morris - Guidebook to Wittgenstein's Tractatus 1E
     A reaction: [Also 2.06 and 2.063] Morris says he must actually mean the second version.
7. Existence / D. Theories of Reality / 8. Facts / d. Negative facts
The world is determined by the facts, and there are no further facts [Wittgenstein]
     Full Idea: The world is determined by the facts, and by these being all the facts.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 1.11), quoted by Michael Potter - The Rise of Analytic Philosophy 1879-1930 47 'Mole'
     A reaction: He is denying negative facts (also written to Russell in 1919). Best approached through truthmakers, I suspect. There is no truthmaker for the supposed factual claim 'there are birds on Mars' - so it is a fact that there are no birds on Mars.
The existence of atomic facts is a positive fact, their non-existence a negative fact [Wittgenstein]
     Full Idea: The existence of atomic facts we also call a positive fact, their non-existence a negative fact. b...The existence and non-existence of atomic facts is the reality. ...[2.063] the total reality is the world.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.06), quoted by Michael Potter - The Rise of Analytic Philosophy 1879-1930 47 'Mole'
     A reaction: Potter observes that he denies negative facts in a1919 letter to Russell, and at 1.11, but then affirms them at 2.06.
On white paper a black spot is a positive fact and a white spot a negative fact [Wittgenstein]
     Full Idea: On white paper, the fact that a point is black corresponds to a positive fact; to the fact that a point is white (not black), a negative fact.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.063), quoted by Michael Potter - The Rise of Analytic Philosophy 1879-1930 08 'Judg'
     A reaction: Elsewhere Wittgenstein is ambiguous as to whether he believes in negative facts [qv].
8. Modes of Existence / A. Relations / 2. Internal Relations
The order of numbers is an internal relation, not an external one [Wittgenstein]
     Full Idea: The order of the number-series is not governed by an external relation but by an internal relation.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.1252)
     A reaction: He seems to mean something like a tautology (see Idea 7968). It is, I take it, part of the concept of any given integer that it has a place in the series. But do the concepts arise self-evidently, or from nature?
A relation is internal if it is unthinkable that its object should not possess it [Wittgenstein]
     Full Idea: A relation is internal if it is unthinkable that its object should not possess it. (This shade of blue and that one stand, eo ipso, in the internal relation of lighter to darker. It is unthinkable that these two objects should not stand in this relation).
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.123)
     A reaction: An epistemological definition. If only one shade of blue existed, would it still have this internal relation? Are things therefore full of potential internal relations with non-existent things?
8. Modes of Existence / C. Powers and Dispositions / 3. Powers as Derived
All powers can be explained by obvious features like size, shape and motion of matter [Descartes]
     Full Idea: There are no powers in stones and plants that are not so mysterious that they cannot be explained …from principles that are known to all and admitted by all, namely the shape, size, position, and motion of particles of matter.
     From: René Descartes (Principles of Philosophy [1646], IV.187), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 23.6
     A reaction: This is an invocation of 'categorical' properties, against dispositions. I take this to be quite wrong. The explanation goes the other way. What supports the structures; what drives the motion; what initiates anything?
8. Modes of Existence / D. Universals / 1. Universals
Five universals: genus, species, difference, property, accident [Descartes]
     Full Idea: The five commonly enumerated universals are: genus, species, difference, property and accident.
     From: René Descartes (Principles of Philosophy [1646], I.59)
     A reaction: Interestingly, this seems to be Descartes passing on his medieval Aristotelian inheritance, in which things are defined by placing them in a class, and then noting what distinguishes them within that class.
8. Modes of Existence / E. Nominalism / 2. Resemblance Nominalism
A universal is a single idea applied to individual things that are similar to one another [Descartes]
     Full Idea: Universals arise solely from the fact that we avail ourselves of one idea in order to think of all individual things that have a certain similitude. When we understand under the same name all the objects represented by this idea, that name is universal.
     From: René Descartes (Principles of Philosophy [1646], I.59)
     A reaction: Judging by the boldness of the pronouncement, it looks as if Descartes hasn't recognised the complexity of the problem. How do we spot a 'similarity', especially an abstraction like 'tool' or 'useful'? This sounds like Descartes trying to avoid Platonism.
9. Objects / A. Existence of Objects / 1. Physical Objects
Objects are the substance of the world [Wittgenstein]
     Full Idea: Objects make up the substance of the world.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.021)
     A reaction: He doesn't say here that the objects are physical, and may be including Frege's abstract objects. His concept of substance seems more like Spinoza than Aristotle.
9. Objects / A. Existence of Objects / 5. Simples
Objects are simple [Wittgenstein]
     Full Idea: Objects are simple
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.02)
     A reaction: Presumably all his objects are 'simples', and what we think of as normal objects are counted by LW as 'facts'.
9. Objects / B. Unity of Objects / 2. Substance / a. Substance
If we perceive an attribute, we infer the existence of some substance [Descartes]
     Full Idea: Based on perceiving the presence of some attribute, we conclude there must also be present an existing thing or substance to which it can be attributed.
     From: René Descartes (Principles of Philosophy [1646], I.52), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 08.1
     A reaction: A rainbow might be a tricky case. This illustrates the persistent belief in substances, even among philosophers who embraced the new corpuscular and mechanistic view of matter.
Apart from the facts, there is only substance [Wittgenstein]
     Full Idea: Substance is what remains independently of what is the case.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.024)
     A reaction: He sees what is the case as comprised of objects, so substance is even more basic. It seems close to Spinoza's single-substance view.
9. Objects / B. Unity of Objects / 2. Substance / d. Substance defined
A substance needs nothing else in order to exist [Descartes]
     Full Idea: By substance we can understand nothing else than a thing which so exists that it needs no other thing in order to exist.
     From: René Descartes (Principles of Philosophy [1646], I.51)
     A reaction: Properties, of course, are the things which have dependent existence. Can properties be reduced to substances (e.g. by adopting a materialist theory of mind)? Note that Descartes does not think that substances depend on God for existence.
9. Objects / D. Essence of Objects / 9. Essence and Properties
A substance has one principal property which is its nature and essence [Descartes]
     Full Idea: Each substance has one principal property that constitutes its nature and essence, to which all its other properties are referred. Extension in length, breadth, and depth constitutes the nature of corporeal substance; and thought of thinking substances.
     From: René Descartes (Principles of Philosophy [1646], I.53), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 08.3
     A reaction: Property is likely to be 'propria', which is a property distinctive of some thing, not just any old modern property. This is quite a strikingly original view of the nature of essence. Descartes despised 'substantial forms'.
To know an object we must know the form and content of its internal properties [Wittgenstein, by Potter]
     Full Idea: Wittgenstein explicitly said that to know an object I must know all its internal properties. ...Internal properties have form and content; form is 'possibility of occurrence in atomic facts' (2.0141), content is its being that specific object (2.0233).
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.01231) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 52 'Simp'
     A reaction: [check original quote] This seems to be an essentialist view of (formal) objects. See Potter 347-9 for discussion. The 'external properties' of an object are the atomic facts in which it occurs.
9. Objects / F. Identity among Objects / 1. Concept of Identity
Identity is not a relation between objects [Wittgenstein]
     Full Idea: It is self-evident that identity is not a relation between objects.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.5301)
     A reaction: Part of Wittgenstein's claim that identity statements are 'pseudo-propositions'. See, in reply, the ideas of McGinn on identity. This was part of the drive that led to the extremes of logical positivism, killing metaphysics for two generations.
9. Objects / F. Identity among Objects / 2. Defining Identity
You can't define identity by same predicates, because two objects with same predicates is assertable [Wittgenstein]
     Full Idea: Russell's definition of identity [x is y if any predicate of x is a predicate of y] won't do, because then one cannot say that two objects have all their properties in common
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.5302), quoted by Michael Potter - The Rise of Analytic Philosophy 1879-1930 53 'Ident'
     A reaction: [The Russell is in Principia] Good. Even if Leibniz is right that no two obejcts have identical properties, it is at least meaningful to consider the possibility. Russell makes it an impossibility, rather than a contingent fact.
9. Objects / F. Identity among Objects / 5. Self-Identity
Two things can't be identical, and self-identity is an empty concept [Wittgenstein]
     Full Idea: Roughly speaking, to say of two things that they are identical is nonsense, and to say of one thing that it is identical with itself is to say nothing at all.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.5303)
     A reaction: Wittgenstein's attack on identity. It is best (following McGinn) to only speak of resemblance between two things (possibly to a very high degree, as in two electrons). Self-identity just is identity; you can drop the word 'identity', but not the concept.
10. Modality / A. Necessity / 3. Types of Necessity
The only necessity is logical necessity [Wittgenstein]
     Full Idea: The only necessity that exists is logical necessity.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.37)
     A reaction: For Wittgenstein that will mean conventional necessity. He is taking a standard Humean view of these things.
10. Modality / D. Knowledge of Modality / 1. A Priori Necessary
The tautologies of logic show the logic of language and the world [Wittgenstein]
     Full Idea: The fact that the propositions of logic are tautologies shows the formal - logical - properties of language and the world.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.12)
     A reaction: This seems to me an extraordinarily hubristic remark (philosophically speaking), especially coming from a work which famously throws away its own ladder. He is very much pursuing Kant's project.
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / a. Conceivable as possible
What is thinkable is possible [Wittgenstein]
     Full Idea: What is thinkable is possible too.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 3.02)
     A reaction: [Plucked from a context!] The modern tide has turned against this idea. The more clearly you understand the facts, the more restricted the possibilities become. If you think the impossible is possible, it is because you are bad at thinking.
10. Modality / E. Possible worlds / 1. Possible Worlds / a. Possible worlds
Each thing is in a space of possible facts [Wittgenstein]
     Full Idea: Each thing is, as it were, in a space of possible states of affairs. This space I can imagine as empty, but not of the thing without the space.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.013)
     A reaction: A clear echo of Kant on natural space. LW calls it 'logical space' (1.13). I take this to be exactly the concept of the space of possibilities which contains the modern notion of possible worlds.
10. Modality / E. Possible worlds / 2. Nature of Possible Worlds / a. Nature of possible worlds
Unlike the modern view of a set of worlds, Wittgenstein thinks of a structured manifold of them [Wittgenstein, by White,RM]
     Full Idea: In 'Tractatus' Wittgenstein is not just thinking of a set of possible worlds (in the modern account), but of a structured manifold within which each 'possible world' is located.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Roger M. White - Wittgenstein's 'Tractatus Logico-Philosophicus' 3 'Positions'
     A reaction: So the modern view has the neutrality of a merely formal system, but LW is thinking of them as the modal structure of reality.
An imagined world must have something in common with the real world [Wittgenstein]
     Full Idea: It is obvious that an imagined world, however different it may be from the real one, must have something - a form - in common with it.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.022)
     A reaction: It is clear that Wittgenstein had a concept of possible worlds close to the modern view.
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
To know an object you must know all its possible occurrences [Wittgenstein]
     Full Idea: If I know an object I also know all its possible occurrences in states of affairs. (Every one of those possibilities must be part of the nature of the object.) A new possibility cannot be discovered later.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.0123)
     A reaction: The requirement that you know them 'all' seems absurd, especially if we need science to discover them. I take this idea to be extremely important, and essentially Aristotelian (connecting with the notion of 'potentiality'). We need to know the powers.
The 'form' of an object is its possible roles in facts [Wittgenstein]
     Full Idea: The possibility of its occurrence in atomic facts is the form of the object.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.0141)
     A reaction: Morris says this picks up the idea from Kant. We might now label the 'form' as the 'modal profile' of the object (a phrase I like). The modern issues over transworld identity seem to be a development of this thought.
10. Modality / E. Possible worlds / 3. Transworld Objects / d. Haecceitism
Two objects may only differ in being different [Wittgenstein]
     Full Idea: If two objects have the same logical form, the only distinction between them, apart from their external properties, is that they are different.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.0233)
     A reaction: This isn't a commitment to haecceities, but it seems to be flirting with the idea. See Simons 1987:241. Kit Fine picks up the idea that objects, as well as sentences, might have 'logical form'. How can being 'different' be primitive? Spatial location?
11. Knowledge Aims / A. Knowledge / 4. Belief / a. Beliefs
We can have knowledge without belief, if others credit us with knowledge [Kusch]
     Full Idea: We can have knowledge that p without believing that p. It is enough that others credit us with the knowledge.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 5)
     A reaction: [He is discussing Welbourne 1993] This is an extreme of the communitarian view.
11. Knowledge Aims / B. Certain Knowledge / 4. The Cogito
Total doubt can't include your existence while doubting [Descartes]
     Full Idea: He who decides to doubt everything cannot nevertheless doubt that he exists while he doubts.
     From: René Descartes (Principles of Philosophy [1646], Pref)
I think, therefore I am, because for a thinking thing to not exist is a contradiction [Descartes]
     Full Idea: There is a contradiction in conceiving that what thinks does not (at the same time as it thinks) exist. Hence this conclusion I think, therefore I am, is the first and most certain that occurs to one who philosophises in an orderly way.
     From: René Descartes (Principles of Philosophy [1646], I.07)
     A reaction: The classic statement of his argument. The significance here is that it seems to have the structure of an argument, as it involves 'philosophising', which leads to a 'contradiction', and hence to the famous conclusion. It is not just intuitive.
'Thought' is all our conscious awareness, including feeling as well as understanding [Descartes]
     Full Idea: By the word 'thought' I understand everything we are conscious of as operating in us. And that is why not only understanding, willing, imagining, but also feeling, are here the same thing as thinking.
     From: René Descartes (Principles of Philosophy [1646], I.09)
     A reaction: There is a bit of tension here between Descartes' correct need to include feeling in thought for his Cogito argument, and his tendency to dismiss animal consciousness, on the grounds that they only sense things, and don't make judgements.
11. Knowledge Aims / C. Knowing Reality / 4. Solipsism
Strict solipsism is pure realism, with the self as a mere point in surrounding reality [Wittgenstein]
     Full Idea: Solipsism, when its implications are followed out strictly, coincides with pure realism. The self of solipsism shrinks to a point without extension, and there remains the reality co-ordinated with it.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.64)
     A reaction: Despite this, Michael Morris is more inclined to see him as an idealist. It is not clear whether the present account of solipsism is idealist or realist. Berkeley seemed to think his idealism was true realism. Can reality be co-ordinated with a point?
Methodological Solipsism assumes all ideas could be derived from one mind [Kusch]
     Full Idea: 'Methodological solipsism' says merely that everyone can conceive of themselves as the only subject. Everyone can construct all referents of their thought and talk out of complexes of their very own experience.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch.19)
     A reaction: The possibility of this can be denied (e.g. by Putnam 1983, dating back to Wittgenstein). I too would doubt it, though finding a good argument seems a forlorn hope.
12. Knowledge Sources / A. A Priori Knowledge / 2. Self-Evidence
If the truth doesn't follow from self-evidence, then self-evidence cannot justify a truth [Wittgenstein]
     Full Idea: If the truth of a proposition does not follow from the fact that it is self-evident to us, then its self-evidence in no way justifies our belief in its truth.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.1363), quoted by Robin Jeshion - Frege's Notion of Self-Evidence 4
     A reaction: Frege seems to have taken self-evidence as intrinsic justification, but Wittgenstein seems to demand a supporting inference. But what is it all based on? Stipulative definitions?
12. Knowledge Sources / A. A Priori Knowledge / 4. A Priori as Necessities
'Nothing comes from nothing' is an eternal truth found within the mind [Descartes]
     Full Idea: The proposition 'nothing comes from nothing' is not to be considered as an existing thing, or the mode of a thing, but as a certain eternal truth which has its seat in our mind and is a common notion or axiom.
     From: René Descartes (Principles of Philosophy [1646], I.49)
     A reaction: There is a tension here, in his assertion that it is 'eternal', but 'not existing'. How does one distinguish an innate idea from an innate truth? 'Eternal' sounds like an external guarantee of truth, but being 'in our mind' sounds less reliable.
12. Knowledge Sources / A. A Priori Knowledge / 5. A Priori Synthetic
The Tractatus aims to reveal the necessities, without appealing to synthetic a priori truths [Wittgenstein, by Morris,M]
     Full Idea: We can see the 'Tractatus' as an attempt to make sense of what is necessarily true of the world - in general, and not just in the mathematical case - without appealing to synthetic a priori truths.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by Michael Morris - Guidebook to Wittgenstein's Tractatus 2H
     A reaction: Morris sees the Tractatus as firmly in the Kantian tradition, and exploring Kant's main project in the first Critique.
There is no a priori order of things [Wittgenstein]
     Full Idea: Whatever we can describe at all could be other than it is. There is no a priori order of things.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.634)
     A reaction: This is his rejection of Kant's dream, of inferring truths about the world by self-examination. However, compare Idea 23495. He clings to the faith that logic reveals 'something' about reality.
12. Knowledge Sources / A. A Priori Knowledge / 8. A Priori as Analytic
Logic and maths can't say anything about the world, since, as tautologies, they are consistent with all realities [Wittgenstein, by Grayling]
     Full Idea: Neither logical nor mathematical propositions say anything about the world, because in virtue of their always being true they are consistent with any way the world could happen to be.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by A.C. Grayling - Wittgenstein Ch.2
     A reaction: This became the standard view for twentieth century empiricists, and appeared to rule out a priori synthetic knowledge forever. Kripke's proposal that there are a posteriori necessities, however, changes the picture.
12. Knowledge Sources / A. A Priori Knowledge / 10. A Priori as Subjective
Logic is a priori because we cannot think illogically [Wittgenstein]
     Full Idea: That logic is a priori consists in the fact that we cannot think illogically.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.4731), quoted by Robin Jeshion - Frege's Notion of Self-Evidence 4
     A reaction: A rather startling claim. Presumably we have to say that when we draw a stupid inference, then we weren't really 'thinking'?
12. Knowledge Sources / A. A Priori Knowledge / 11. Denying the A Priori
No pictures are true a priori [Wittgenstein]
     Full Idea: There are no pictures that are true a priori.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.225)
     A reaction: This is part of the growing modern doubts about the scope or possibility of a priori knowledge. A 'picture' here is the mental model which is the meaning of a proposition.
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / b. Basic beliefs
We can know basic Principles without further knowledge, but not the other way round [Descartes]
     Full Idea: It is on the Principles, or first causes, that the knowledge of other things depends, so the Principles can be known without these last, but the other things cannot reciprocally be known without the Principles.
     From: René Descartes (Principles of Philosophy [1646], Pref)
     A reaction: A particularly strong assertion of foundationalism, as it says that not only must the foundations exist, but also we must actually know them. This sounds false, as elementary knowledge then seems to require far too much sophistication.
13. Knowledge Criteria / B. Internal Justification / 4. Foundationalism / f. Foundationalism critique
Foundations seem utterly private, even from oneself at a later time [Kusch]
     Full Idea: Foundationalists place the foundations of knowledge at a point where they are in principle accessible only to the individual knower. They cannot be 'shared' with another person, or with oneself at a later time.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 8)
     A reaction: Kusch is defending an extremely social view of knowledge. Being private to an individual may just he an unfortunate epistemological fact. Being unavailable even to one's later self seems a real problem for foundational certainty.
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / a. Coherence as justification
Testimony is reliable if it coheres with evidence for a belief, and with other beliefs [Kusch]
     Full Idea: Testimony must be reliable since its deliveries cohere both with input from other information routes in the formation of single beliefs, and with other types of beliefs in the formation of systems of belief.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 4)
     A reaction: Kusch criticises this view (credited to C.A.J. Coady 1992) as too individualistic , but it sounds to me dead right. I take a major appeal of the coherence account of justification to be its capacity to extend seamlessly out into external testimony.
The coherentist restricts the space of reasons to the realm of beliefs [Kusch]
     Full Idea: The coherentist restricts the space of reasons to the realm of beliefs.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 8)
     A reaction: I endorse this idea, which endorses Davidson's slogan on the subject. The key thought is that a 'pure' sensation is uninterpreted, and so cannot justify anything. It is only once it generates a proposition that it can justify. But McDowell 1994.
13. Knowledge Criteria / B. Internal Justification / 5. Coherentism / c. Coherentism critique
Individualistic coherentism lacks access to all of my beliefs, or critical judgement of my assessment [Kusch]
     Full Idea: Individualistic versions of coherentism assume that a belief is justified if it fits with all, or most, of my contemporaneous beliefs. But who has access to that totality? Who can judge my assessment? From what position could it be judged?
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 8)
     A reaction: [compressed] Though I agree with Kusch on the social aspect of coherence, I don't think these are major criticisms. Who can access, or critically evaluate a society's body of supposedly coherent beliefs? We just do our best.
Individual coherentism cannot generate the necessary normativity [Kusch]
     Full Idea: Standard forms of coherentism are unable to account for normativity, because of their common individualism. Normativity cannot be generated within the isolated individual, or in the causal interaction between world and individual mind.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch.10)
     A reaction: This thought leads to belief in rationalism and the a priori, not (as Kusch hopes) to the social dimension. How can social normativity get off the ground if there is none of it to be found in individuals? The criteria of coherence seem to be given.
13. Knowledge Criteria / C. External Justification / 2. Causal Justification
Cultures decide causal routes, and they can be critically assessed [Kusch]
     Full Idea: Assessments of causal routes are specific to cultures, and thus not beyond dialectical justification.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch.11)
     A reaction: This is a good defence of the social and communitarian view against those who are trying to be thoroughly naturalistic and physicalist by relying entirely on causal processes for all explanation, even though I sympathise with such naturalism.
13. Knowledge Criteria / C. External Justification / 3. Reliabilism / a. Reliable knowledge
Process reliabilism has been called 'virtue epistemology', resting on perception, memory, reason [Kusch]
     Full Idea: Process reliabilism is sometimes subsumed under the label 'virtue epistemology', so that processes are 'epistemically virtuous' if they lead mostly to true beliefs. The 'intellectual virtues' here are perception, memory or reasoning.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 9)
     A reaction: I am shocked that 'intellectual virtue' should be hijacked by reliabilists, suggesting that it even applies to a good clock. I like the Aristotelian idea that sound knowledge rests on qualities of character in the knower - including social qualities.
13. Knowledge Criteria / C. External Justification / 6. Contextual Justification / a. Contextualism
Justification depends on the audience and one's social role [Kusch]
     Full Idea: How a claim (about an X-ray) needs to be justified depends on whether one is confronted by a group of laypersons, or of experts, and is prescribed by one's social role.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 8)
     A reaction: I think this is exactly right. I cannot think of any absolute criterion for justification which doesn't play straight into the hands of sceptics. Final and certain justification is an incoherent notion. But I am a little more individualistic than Kusch.
13. Knowledge Criteria / C. External Justification / 7. Testimony
Testimony is an area in which epistemology meets ethics [Kusch]
     Full Idea: Testimony is an area in which epistemology meets ethics.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 5)
     A reaction: This is very thought-provoking. A key concept linking the two would be 'respect'. Consider also 'experts'.
Powerless people are assumed to be unreliable, even about their own lives [Kusch]
     Full Idea: The powerless in society are not usually taken to be trustworthy witnesses even when it comes to providing information about their own lives.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 5)
     A reaction: This is where epistemology shades off into politics and the writings of Foucault.
Testimony does not just transmit knowledge between individuals - it actually generates knowledge [Kusch]
     Full Idea: Testimony is not just a means of transmission of complete items of knowledge from and to an individual. Testimony is almost always generative of knowledge.
     From: Martin Kusch (Knowledge by Agreement [2002], Intro)
     A reaction: I'm not clear how my testimony could fail to be knowledge for me, but become knowledge just because I pass it to you. I might understand what I say better than you did. When fools pool their testimony, presumably not much knowledge results.
Some want to reduce testimony to foundations of perceptions, memories and inferences [Kusch]
     Full Idea: Reductionalists about testimony are foundationalists by temperament. ...Their project amounts to justifying our testimonial beliefs in terms of perceptions, memories and inferences.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 4)
     A reaction: Kusch wants to claim that the sharing of testimony is the means by which knowledge is created. My line is something like knowledge being founded on a social coherence, which is an extension of internal individual coherence.
Testimony won't reduce to perception, if perception depends on social concepts and categories [Kusch]
     Full Idea: How can we hope to reduce testimony to perception if the way we perceive the world is to a considerable extent shaped by concepts and categories that we have learned from others?
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 4)
     A reaction: To me this sounds like good support for coherentism, the benign circle between my reason, my experience, and the testimony and reason of others. Asking how the circle could get started shows ignorance of biology.
A foundation is what is intelligible, hence from a rational source, and tending towards truth [Kusch]
     Full Idea: It can be argued that testimony is non-reductive because it relies on the fact that whatever is intelligible is likely to come from a rational source, and that rational sources, by their very nature, tend towards the truth.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 4 n7)
     A reaction: [He cites Tyler Burge 1993, 1997] If this makes testimony non-reductive, how would one assess whether the testimony is 'intelligible'?
Vindicating testimony is an expression of individualism [Kusch]
     Full Idea: To believe that testimony needs a general vindication is itself an expression of individualism.
     From: Martin Kusch (Knowledge by Agreement [2002], Intro)
     A reaction: Kusch is a spokesman for Communitarian Epistemology. Surely we are allowed to identify the criteria for what makes a good witness? Ask a policeman.
13. Knowledge Criteria / C. External Justification / 8. Social Justification
Myths about lonely genius are based on epistemological individualism [Kusch]
     Full Idea: Many myths about the lonely scientific genius underwrite epistemological individualism.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 5)
     A reaction: They all actually say that they 'stood on the shoulders of giants', and they are invariably immersed in the contemporary researches of teams of like-minded people. How surprised were the really expert contemporaries by Newton, Einstein, Gödel?
Communitarian Epistemology says 'knowledge' is a social status granted to groups of people [Kusch]
     Full Idea: I propose 'communitarian epistemology' - claiming first that the term 'knowledge' marks a social status, and is dependent on the existence of communities, and second that this social status is typically granted to groups of people.
     From: Martin Kusch (Knowledge by Agreement [2002], Intro)
     A reaction: I find this very congenial, though Kusch goes a little far when he claims that knowledge is largely created by social groups. He allows that Robinson Crusoe might have knowledge of his island, but can't give a decent account of it.
Private justification is justification to imagined other people [Kusch]
     Full Idea: Coming to convince myself is actually to form a pretend communal belief with pretend others, ..which is clearly parasitic on the case where the others are real.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch.11)
     A reaction: This slightly desperate move is a way for 'communitarian' epistemologists to deal with Robinson Crusoe cases. I think Kusch is right, but it is a bit hard to prove that this is what is 'actually' going on.
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
Doubts can't exist if they are inexpressible or unanswerable [Wittgenstein]
     Full Idea: Doubt can exist only where a question exists, a question only where an answer can exist, and an answer only where something can be said.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.51)
     A reaction: I don't agree with any of that. It is typical of the phase when philosophers were mesmerised by language. Cats look puzzled sometimes. A glimmering of doubt may be pre-linguistic, inexpressible and unanswerable, but still feels like a doubt.
14. Science / B. Scientific Theories / 3. Instrumentalism
The 'Tractatus' is instrumentalist about laws of nature [Wittgenstein, by Armstrong]
     Full Idea: Wittgenstein is an instrumentalist about laws of nature in 'Tractatus'.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by David M. Armstrong - What is a Law of Nature? 01.3
     A reaction: [I record this, but don't know the reference]
14. Science / C. Induction / 2. Aims of Induction
Induction accepts the simplest law that fits our experiences [Wittgenstein]
     Full Idea: The procedure of induction consists in accepting as true the simplest law that can be reconciled with our experiences.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.363)
14. Science / D. Explanation / 2. Types of Explanation / e. Lawlike explanations
The modern worldview is based on the illusion that laws explain nature [Wittgenstein]
     Full Idea: The whole modern conception of the world is founded on the illusion that the so-called laws of nature are the explanations of natural phenomena.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.371)
     A reaction: Love it! Not only does it say that lawlike explanation is wrong, but it registers that this is a profound feature of the modern view of the world, and not just a slightly misguided philosophical theory.
15. Nature of Minds / B. Features of Minds / 1. Consciousness / b. Essence of consciousness
We can understand thinking occuring without imagination or sensation [Descartes]
     Full Idea: We can understand thinking without imagination or sensation, as is quite clear to anyone who attends to the matter.
     From: René Descartes (Principles of Philosophy [1646], I.53)
     A reaction: We may certainly take it that Descartes means if it is understandable then it is logically possible. To believe that thinking could occur without imagination strikes me as an astonishing error. I take imagination to be more central than understanding.
16. Persons / B. Nature of the Self / 4. Presupposition of Self
The subject stands outside our understanding of the world [Wittgenstein]
     Full Idea: The subject does not belong to the world; rather, it is a limit of the world.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.632)
     A reaction: Interesting. We must not confuse epistemology with ontology, but the perceived world exists between two limits - the farthest reaches of my perceptions, and the farthest reaches of myself. I wish I could clearly disentangle the nearer border. Dasein?
16. Persons / D. Continuity of the Self / 7. Self and Thinking
In thinking we shut ourselves off from other substances, showing our identity and separateness [Descartes]
     Full Idea: Because each one of us understands what he thinks, and that in thinking he can shut himself off from every other substance, we may conclude that each of us is really distinct from every other thinking substance and from corporeal substance.
     From: René Descartes (Principles of Philosophy [1646], I.60)
     A reaction: This seems to be a novel argument which requires elucidation. I can 'shut myself off from every other substance'? If I shut myself off from thinking about food, does that mean hunger is not part of me? Or convince yourself that you don't have a brother?
16. Persons / E. Rejecting the Self / 2. Self as Social Construct
To be considered 'an individual' is performed by a society [Kusch]
     Full Idea: One cannot even have the social status of 'being an individual' unless it has been conferred on one by a communal performative belief.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch.11)
     A reaction: This sounds crazy until you think of the mentality of a tenth generation slave in a fully slave-owning society.
16. Persons / E. Rejecting the Self / 4. Denial of the Self
The modern idea of the subjective soul is composite, and impossible [Wittgenstein]
     Full Idea: Therre is no such thing as the soul - the subject, etc. - as it is conceived in the superficial psychology of the present day. Indeed a composite soul would no longer be a soul.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.5421)
     A reaction: This seems to endorse Descartes' claim about the essential unity of the mind. I think Hume is in the background of LW's thought. Presumably the psychologist offered a 'composite' view. Prior discussion of belief leads into this remark.
16. Persons / F. Free Will / 1. Nature of Free Will
Our free will is so self-evident to us that it must be a basic innate idea [Descartes]
     Full Idea: It is so evident that we are possessed of a free will that can give or withhold its assent, that this may be counted as one of the first and most common notions found innately in us.
     From: René Descartes (Principles of Philosophy [1646], I.39)
     A reaction: It seems to me plausible to say that we have an innate conception of our own will (our ability to make decisions), though Hume says we only learn about the will from experience, but the idea that it is absolutely 'free' might never cross our minds.
17. Mind and Body / A. Mind-Body Dualism / 1. Dualism
There are two ultimate classes of existence: thinking substance and extended substance [Descartes]
     Full Idea: I observe two ultimate classes of things: intellectual or thinking things, pertaining to the mind or to thinking substance, and material things, pertaining to extended substance or to body.
     From: René Descartes (Principles of Philosophy [1646], I.48)
     A reaction: This is clear confirmation that Descartes believed the mind is a substance, rather than an insubstantial world of thinking. It leaves open the possibility of a different theory: that mind is not a substance, but is a Platonic adjunct to reality.
17. Mind and Body / D. Property Dualism / 5. Supervenience of mind
Even if tightly united, mind and body are different, as God could separate them [Descartes]
     Full Idea: Even if we suppose God had united a body and a soul so closely that they couldn't be closer, and made a single thing out of the two, they would still remain distinct, because God has the power of separating them, or conserving out without the other.
     From: René Descartes (Principles of Philosophy [1646], I.60)
     A reaction: If Descartes lost his belief in God (after discussing existence with Kant) would he cease to be a dualist? This quotation seems to be close to conceding a mind-body relationship more like supervenience than interaction.
18. Thought / A. Modes of Thought / 6. Judgement / b. Error
Most errors of judgement result from an inaccurate perception of the facts [Descartes]
     Full Idea: What usually misleads us is that we very frequently form a judgement although we do not have an accurate perception of what we judge.
     From: René Descartes (Principles of Philosophy [1646], I.33)
     A reaction: This seems to me a generally accurate observation, particularly in the making of moral judgements (which was probably not what Descartes was considering). The implication is that judgements are to a large extent forced by our perceptions.
The form of a proposition must show why nonsense is unjudgeable [Wittgenstein]
     Full Idea: The correct explanation of the form of the proposition 'A judges p' must show that it is impossible to judge a nonsense. (Russell's theory does not satisfy this condition).
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.5422)
     A reaction: In Notebooks p.96 LW gives the example 'this table penholders the book'. I take it Russell wanted judgement to impose unified meaning on sentences, but LW shows that assembling meaning must precede judgement. LW is right.
18. Thought / D. Concepts / 1. Concepts / a. Nature of concepts
Our experience may be conceptual, but surely not the world itself? [Kusch]
     Full Idea: I am unconvinced by McDowell's arguments in favour of treating the world as itself conceptual. Granted that our experience is conceptual in quality; it still does not follow that the world itself is conceptual.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 9)
     A reaction: I would take Kusch's point to be a given in any discussion of concepts, and McDowell as a non-starter on this one. I am inclined to believe that we do have non-conceptual experiences, but I take them to be epistemologically useless.
18. Thought / D. Concepts / 5. Concepts and Language / a. Concepts and language
What can be said is what can be thought, so language shows the limits of thought [Wittgenstein, by Grayling]
     Full Idea: In Wittgenstein's view, what can be said is the same as what can be thought; so that once one has grasped the nature of language, one has shown the limit beyond which language and thought become nonsense.
     From: report of Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921]) by A.C. Grayling - Wittgenstein Ch.2
     A reaction: I just don't believe that what is thinkable is limited to what is expressible. A lot of philosophy is the struggle to find expression for thoughts which are just beyond the edge of current language. See Idea 6870.
19. Language / A. Nature of Meaning / 2. Meaning as Mental
The 'form' of the picture is its possible combinations [Wittgenstein]
     Full Idea: The form of depiction is the possibility that the things are combined with one another as are the elements of the picture.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.151)
     A reaction: This is why 'model' (or even 'simulation'?) is a better term than 'picture' for his proposal. Pictures are fixed, but models can be adjusted.
19. Language / A. Nature of Meaning / 4. Meaning as Truth-Conditions
To understand a proposition means to know what is the case if it is true [Wittgenstein]
     Full Idea: To understand a proposition means to know what is the case if it is true.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.024)
     A reaction: This established the Frege truth-conditions theory of meaning, which was expanded by Davidson, and then possible worlds semantics. You can't assess truth without knowing meaning. Dummett says the two go together.
19. Language / A. Nature of Meaning / 5. Meaning as Verification
Good philosophy asserts science, and demonstrates the meaninglessness of metaphysics [Wittgenstein]
     Full Idea: The correct method in philosophy would be to say nothing except what can be said, i.e. propositions of natural science, and whenever someone wanted to say something metaphysical, to show that he had failed to give a meaning to signs in his propositions.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.53)
     A reaction: This seems to be the germ of logical positivism, picked up by the Vienna Circle, and passed on the Ayer and co. How, though, do you 'show' that a sign is meaningless? Very abstract ideas are too far away from experience to be analysed that way.
19. Language / C. Assigning Meanings / 4. Compositionality
Propositions use old expressions for a new sense [Wittgenstein]
     Full Idea: A proposition must use old expressions to communicate a new sense.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.03)
     A reaction: A nicely expressed affirmation of the principle of compositionality. It entails that the propositions can be either true or false, according to LW.
Propositions are understood via their constituents [Wittgenstein]
     Full Idea: A proposition is understood by anyone who understands its constituents.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.024)
     A reaction: The 'constituents' had better include the grammatical relationships. Otherwise it's 'rearrange these words to make a well known saying'. That said, this strikes me as an important truth about language. We assemble sentence meanings.
19. Language / D. Propositions / 2. Abstract Propositions / b. Propositions as possible worlds
Pictures are possible situations in logical space [Wittgenstein]
     Full Idea: A picture represents a possible situation in logical space.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 2.202)
     A reaction: This seems pretty close to the idea that propositions are sets of possible worlds (though that seems to add unnecessary extra baggage). If they just picture situations, why does he mention logical space? Within the limits of possible picturing?
19. Language / F. Communication / 1. Rhetoric
Often socialising people is the only way to persuade them [Kusch]
     Full Idea: Often we can convince members of other cultures only by socializing them into our culture.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch.19)
     A reaction: This looks both true and interesting, and is good support for Kusch's communitarian epistemology. What actually persuades certainly doesn't have to be reasons, and may be almost entirely social.
19. Language / F. Communication / 4. Private Language
Solipsism is correct, but can only be shown, not said, by the limits of my personal language [Wittgenstein]
     Full Idea: What the solipsist means is quite correct; only it cannot be said, but makes itself manifest. The world is my world: this is manifest in the fact that the limits of language (of that language which I alone understand) mean the limits of my world.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 5.62)
     A reaction: I take it that LW later showed that the remark in brackets is absurd, using his Private Language argument. Commentators seem unclear about how seriously to take this claim.
19. Language / F. Communication / 6. Interpreting Language / a. Translation
We translate by means of proposition constituents, not by whole propositions [Wittgenstein]
     Full Idea: When translating one language into another, we do not proceed by translating each proposition of the one into a proposition of the other, but merely by translating the constituents of propositions.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 4.025)
     A reaction: This seems opposed to Quine's later holistic view of translating whole languages. Is he objecting to Frege's context principle?
20. Action / C. Motives for Action / 4. Responsibility for Actions
We do not praise the acts of an efficient automaton, as their acts are necessary [Descartes]
     Full Idea: We do not praise automata, although they respond exactly to the movements they were designed to produce, since their actions are performed necessarily
     From: René Descartes (Principles of Philosophy [1646], I.37)
     A reaction: I say we attribute responsibility when we perceive something like a 'person' as causing them. We don't blame small animals, because there is 'no one at home', but we blame children as they develop a full character and identity. We can ignore free will.
The greatest perfection of man is to act by free will, and thus merit praise or blame [Descartes]
     Full Idea: That the will should extend widely accords with its nature, and it is the greatest perfection in man to be able to act by its means, that is, freely, and by so doing we are in peculiar way masters of our actions, and thereby merit praise or blame.
     From: René Descartes (Principles of Philosophy [1646], I.37)
     A reaction: This seems to me to be a deep-rooted and false understanding which philosophy has inherited from theology. It doesn't strike me that there must an absolute 'buck-stop' to make us responsible. Why is it better for a decision to appear out of nowhere?
22. Metaethics / A. Ethics Foundations / 1. Nature of Ethics / b. Defining ethics
Ethics cannot be put into words [Wittgenstein]
     Full Idea: Ethics cannot be put into words.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.421)
     A reaction: Nonsense. There is lots of good writing about ethics. This is evasive mysticism.
22. Metaethics / B. Value / 1. Nature of Value / c. Objective value
The sense of the world must lie outside the world [Wittgenstein]
     Full Idea: The sense of the world must lie outside the world.
     From: Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 6.41)
     A reaction: Since I don't believe that anything 'lies outside the world' I can't make sense of this. He implies that the Self lies outside of the world (to the point of solipsism), so I suppose that's it.
24. Political Theory / D. Ideologies / 7. Communitarianism / a. Communitarianism
Communitarianism in epistemology sees the community as the primary knower [Kusch]
     Full Idea: Communitarianism in epistemology sees the community as the primary knower.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 5)
     A reaction: This thought offers an account of epistemology which could fit in with communitarian political views. See the ideas of Martin Kusch in this database.
26. Natural Theory / A. Speculations on Nature / 1. Nature
Physics only needs geometry or abstract mathematics, which can explain and demonstrate everything [Descartes]
     Full Idea: I do not accept or desire any other principle in physics than in geometry or abstract mathematics, because all the phenomena of nature may be explained by their means, and sure demonstrations can be given of them.
     From: René Descartes (Principles of Philosophy [1646], 2.64), quoted by Peter Alexander - Ideas, Qualities and Corpuscles 7
     A reaction: This is his famous and rather extreme view, which might be described as hyper-pythagoreanism (by adding geometry to numbers). It seems to leave out matter, forces and activity.
26. Natural Theory / A. Speculations on Nature / 2. Natural Purpose / c. Purpose denied
We will not try to understand natural or divine ends, or final causes [Descartes]
     Full Idea: We will not seek for the reason of natural things from the end which God or nature has set before him in their creation .
     From: René Descartes (Principles of Philosophy [1646], §28)
     A reaction: Teleology is more relevant to biology than to the other sciences, and it is hard to understand an eye without a notion of 'what it is for'. Planetary motion reveals nothing about purposes. If you demand a purpose, it becomes more baffling.
26. Natural Theory / A. Speculations on Nature / 7. Later Matter Theories / c. Matter as extension
Matter is not hard, heavy or coloured, but merely extended in space [Descartes]
     Full Idea: The nature of matter, or body viewed as a whole, consists not in its being something which is hard, heavy, or colored, or which in any other way affects the senses, but only in its being a thing extended in length, breadth and depth.
     From: René Descartes (Principles of Philosophy [1646], 2.4), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 04.5
26. Natural Theory / B. Natural Kinds / 7. Critique of Kinds
Natural kinds are social institutions [Kusch]
     Full Idea: Natural kinds are social institutions.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch.11)
     A reaction: I can see what he means, but I take this to be deeply wrong. A clarification of what exactly is meant by a 'natural kind' is needed before we can make any progress with this one. Is a village a natural kind? Or a poodle? Or a shoal?
28. God / A. Divine Nature / 4. Divine Contradictions
Omniscience is incoherent, since knowledge is a social concept [Kusch]
     Full Idea: The very idea of omniscience is dubious, at least for the communitarian epistemologist, since knowing is a social state, and knowledge is a social status, needing a position in a social network.
     From: Martin Kusch (Knowledge by Agreement [2002], Ch. 4)
     A reaction: A nice test case. Would an omniscient mind have evidence for its beliefs? Would it continually check for coherence? Is it open to criticism? Does it even entertain the possibility of error? Could another 'omniscient' mind challenge it?