130 ideas
| 19359 | Leibniz aims to give coherent rational support for empiricism [Leibniz, by Perkins] |
| Full Idea: Leibniz's philosophy largely serves to justify and enable a coherent empirical account of the world. | |
| From: report of Gottfried Leibniz (works [1690]) by Franklin Perkins - Leibniz: Guide for the Perplexed 4.I | |
| A reaction: A nice counter to the simplistic idea of Locke as empiricist and Leibniz as rationalist. Leibniz is explicit that science needs a separate 'metaphysics' to underpin it. Perkins says Locke constructs experience, and Leibniz analyses it. |
| 13086 | Metaphysics is a science of the intelligible nature of being [Leibniz, by Cover/O'Leary-Hawthorne] |
| Full Idea: For Leibniz, metaphysics is above all a science of the intelligible nature of being. | |
| From: report of Gottfried Leibniz (works [1690]) by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 4.3.1 | |
| A reaction: [Their footnote gives two quotes in support] I could take this as my motto. We are not studying the 'nature of being', because we can't. We are studying what is 'intelligible' about it; my thesis is that the need for intelligibility imposes an order. |
| 16710 | Leibniz tried to combine mechanistic physics with scholastic metaphysics [Leibniz, by Pasnau] |
| Full Idea: Leibniz made a sustained attempt to combine a mechanistic physics with something like a scholastic metaphysics. | |
| From: report of Gottfried Leibniz (works [1690]) by Robert Pasnau - Metaphysical Themes 1274-1671 20.1 | |
| A reaction: This seems to me clear enough, and a lot of current philosophers seem to underestimate how Aristotelian Leibniz was. |
| 16897 | Reason is the faculty for grasping apriori necessary truths [Leibniz, by Burge] |
| Full Idea: Leibniz actually characterises reason as the faculty for apprehending priori, necessary truths. | |
| From: report of Gottfried Leibniz (works [1690]) by Tyler Burge - Frege on Apriority (with ps) 2 | |
| A reaction: No wonder it is called the Age of Reason when the claims are this grandiose. |
| 24047 | An account is either a definition or a demonstration [Aristotle] |
| Full Idea: Every account is either a definition or a demonstration. | |
| From: Aristotle (De Anima [c.329 BCE], 407a24) | |
| A reaction: That is, it is either a summary of the thing's essential nature, or it is a proof of some natural fact, starting from first principles. |
| 3346 | For Leibniz rationality is based on non-contradiction and the principle of sufficient reason [Leibniz, by Benardete,JA] |
| Full Idea: Leibniz distinguished two fundamental principles of rationality - the principle of non-contradiction and the principle of sufficient reason. | |
| From: report of Gottfried Leibniz (works [1690]) by José A. Benardete - Metaphysics: the logical approach Ch.18 |
| 3347 | Leibniz said the principle of sufficient reason is synthetic a priori, since its denial is not illogical [Leibniz, by Benardete,JA] |
| Full Idea: Leibniz assigns synthetic a priori status to the principle of sufficient reason, readily conceding that one can deny it without fear of inconsistency. | |
| From: report of Gottfried Leibniz (works [1690]) by José A. Benardete - Metaphysics: the logical approach Ch.18 |
| 4643 | The Principle of Sufficient Reason does not presuppose that all explanations will be causal explanations [Baggini /Fosl] |
| Full Idea: The Principle of Sufficient Reason does not presuppose that all explanations will be causal explanations. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §3.28) | |
| A reaction: This sounds a reasonable note of caution, but doesn't carry much weight unless some type of non-causal reason can be envisaged. God's free will? Our free will? The laws of causation? |
| 4633 | You cannot rationally deny the principle of non-contradiction, because all reasoning requires it [Baggini /Fosl] |
| Full Idea: Anyone who denies the principle of non-contradiction simultaneously affirms it; it cannot be rationally criticised, because it is presupposed by all rationality. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §1.12) | |
| A reaction: Nietzsche certainly wasn't afraid to ask why we should reject something because it is a contradiction. The 'logic of personal advantage' might allow logical contradictions. |
| 24052 | From one thing alone we can infer its contrary [Aristotle] |
| Full Idea: One member of a pair of contraries is sufficient to discern both itself and its opposite. | |
| From: Aristotle (De Anima [c.329 BCE], 411a02) | |
| A reaction: This obviously requires prior knowledge of what the opposite is. He says you can infer the crooked from the straight. You can hardly use light in isolation to infer dark [see DA 418b17]. What's the opposite of a pig? |
| 4635 | Dialectic aims at unified truth, unlike analysis, which divides into parts [Baggini /Fosl] |
| Full Idea: Dialectic can be said to aim at wholeness or unity, while 'analytic' thinking divides that with which it deals into parts. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §2.03) | |
| A reaction: I don't accept this division (linked here to Hegel). I am a fan of analysis, as practised by Aristotle, but it is like dismantling an engine to identify and clean the parts, before reassembling it more efficiently. |
| 8627 | Leibniz is inclined to regard all truths as provable [Leibniz, by Frege] |
| Full Idea: Leibniz has an inclination to regard all truths as provable. | |
| From: report of Gottfried Leibniz (works [1690]) by Gottlob Frege - Grundlagen der Arithmetik (Foundations) §15 | |
| A reaction: Leibniz sounds like the epitome of Enlightenment optimism about the powers of reason. Could God prove every truth? It's a nice thought. |
| 4632 | 'Natural' systems of deduction are based on normal rational practice, rather than on axioms [Baggini /Fosl] |
| Full Idea: A 'natural' system of deduction does not posit any axioms, but looks instead for its formulae to the practices of ordinary rationality. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §1.09) | |
| A reaction: Presumably there is some middle ground, where we attempt to infer the axioms of normal practice, and then build a strict system on them. We must be allowed to criticise 'normal' rationality, I hope. |
| 4631 | In ideal circumstances, an axiom should be such that no rational agent could possibly object to its use [Baggini /Fosl] |
| Full Idea: In ideal circumstances, an axiom should be such that no rational agent could possibly object to its use. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §1.09) | |
| A reaction: Yes, but the trouble is that all our notions of 'rational' (giving reasons, being consistent) break down when we look at unsupported axioms. In what sense is something rational if it is self-evident? |
| 4638 | The principle of bivalence distorts reality, as when claiming that a person is or is not 'thin' [Baggini /Fosl] |
| Full Idea: Forcing everything into the straightjacket of bivalence seriously distorts the world. The problem is most acute in the case of vague concepts, such as thinness. It is not straightforwardly true or false that a person is thin. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §3.03) | |
| A reaction: Can't argue with that. Can we divide all our concepts into either bivalent or vague? Presumably both propositions and concepts could be bivalent. |
| 1729 | We perceive number by the denial of continuity [Aristotle] |
| Full Idea: Number we perceive by the denial of continuity. | |
| From: Aristotle (De Anima [c.329 BCE], 425a19) | |
| A reaction: This is a key thought. A being (call it 'Parmenides') which sees all Being as One would make no distinctions of identity, and so could not count anything. Why would they want numbers? |
| 9147 | Number cannot be defined as addition of ones, since that needs the number; it is a single act of abstraction [Fine,K on Leibniz] |
| Full Idea: Leibniz's talk of the addition of ones cannot define number, since it cannot be specified how often they are added without using the number itself. Number must be an organic unity of ones, achieved by a single act of abstraction. | |
| From: comment on Gottfried Leibniz (works [1690]) by Kit Fine - Cantorian Abstraction: Recon. and Defence §1 | |
| A reaction: I doubt whether 'abstraction' is the right word for this part of the process. It seems more like a 'gestalt'. The first point is clearly right, that it is the wrong way round if you try to define number by means of addition. |
| 19375 | The continuum is not divided like sand, but folded like paper [Leibniz, by Arthur,R] |
| Full Idea: Leibniz said the division of the continuum should not be conceived 'to be like the division of sand into grains, but like that of a tunic or a sheet of paper into folds'. | |
| From: report of Gottfried Leibniz (works [1690], A VI iii 555) by Richard T.W. Arthur - Leibniz | |
| A reaction: This from the man who invented calculus. This thought might apply well to the modern physicist's concept of a 'field'. |
| 18080 | A tangent is a line connecting two points on a curve that are infinitely close together [Leibniz] |
| Full Idea: We have only to keep in mind that to find a tangent means to draw a line that connects two points of a curve at an infinitely small distance. | |
| From: Gottfried Leibniz (works [1690]), quoted by Philip Kitcher - The Nature of Mathematical Knowledge 10.1 | |
| A reaction: [The quote can be tracked through Kitcher's footnote] |
| 18081 | Nature uses the infinite everywhere [Leibniz] |
| Full Idea: Nature uses the infinite in everything it does. | |
| From: Gottfried Leibniz (works [1690]), quoted by Philip Kitcher - The Nature of Mathematical Knowledge 10.1 | |
| A reaction: [The quote can be tracked through Kitcher's footnote] He seems to have had in mind the infinitely small. |
| 24057 | What is prior is always potentially present in what is next in order [Aristotle] |
| Full Idea: What is prior is always potentially present in what is next in order … - for example, the triangle in the quadrilateral, or the nutritive part of animate things in the perceptual part. | |
| From: Aristotle (De Anima [c.329 BCE], 414a28) | |
| A reaction: 'Prior' seems to be a value for Aristotle, which is never present in modern discussions of ontological relations and structure. Priority tracks back to first principles. |
| 7565 | Leibniz proposes monads, since there must be basic things, which are immaterial in order to have unity [Leibniz, by Jolley] |
| Full Idea: Leibniz believes in monads because it would be contrary to reason or divine wisdom if everything was compounds, down to infinity; there must be ultimate unified building-blocks; they cannot be material, for material things lack genuine unity. | |
| From: report of Gottfried Leibniz (works [1690]) by Nicholas Jolley - Leibniz Ch.3 | |
| A reaction: It is hard to discern the basis for the claim that only immaterial things can have unity. The Greeks proposed atoms, and we have no reason to think that electrons lack unity. |
| 10419 | If relations can be reduced to, or supervene on, monadic properties of relata, they are not real [Leibniz, by Swoyer] |
| Full Idea: Leibniz argued that relations could be reduced to monadic properties and so were dispensable, and some still agree, saying relations supervene on monadic properties of the relata, and are not actually real. | |
| From: report of Gottfried Leibniz (works [1690]) by Chris Swoyer - Properties 7.4 | |
| A reaction: At the very least a background of space and/or time seem required, in addition to any properties the relata may have. y only becomes 'to the left of x' when x appears to its right, so the relation doesn't seem to be intrinsic to y. |
| 13078 | Relations aren't in any monad, so they are distributed, so they are not real [Leibniz] |
| Full Idea: The relations which connect two monads are not in either the one or the other, but equally in both at once; and therefore properly speaking, in neither. I do not think you would wish to posit an accident which would inhere simultaneously in two subjects. | |
| From: Gottfried Leibniz (works [1690], G II:517), quoted by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 2.4.3 | |
| A reaction: Where Russell affirms relations as universals, and scholastics make them properties of individuals, Leibniz denies their reality entirely. It seems obvious that once the objects and properties are there, the relations come for free. |
| 16752 | Sight is the essence of the eye, fitting its definition; the eye itself is just the matter [Aristotle] |
| Full Idea: If the eye were an animal, sight would have been its soul, for sight is the substance or essence of the eye which corresponds to the formula, the eye being merely the matter of seeing; when seeing is removed it is no longer an eye,except in name. | |
| From: Aristotle (De Anima [c.329 BCE], 412b18) | |
| A reaction: This is a drastic view of form as merely function, which occasionally appears in Aristotle. To say a blind eye is not an eye is a tricky move in metaphysics. So what is it? In some sense it is still an eye. |
| 12713 | Forms have sensation and appetite, the latter being the ability to act on other bodies [Leibniz, by Garber] |
| Full Idea: Leibniz's form contains both sensation and appetite, and he seems to associate appetite with the ability a body has to act on another. | |
| From: report of Gottfried Leibniz (works [1690]) by Daniel Garber - Leibniz:Body,Substance,Monad 3 | |
| A reaction: It strikes me (you may be surprised to hear) that this concept is not unlike Nietzsche's all-mastering 'will to power'. I offer Idea 7140 in evidence. |
| 13087 | The essence of a thing is its real possibilities [Leibniz, by Cover/O'Leary-Hawthorne] |
| Full Idea: In Leibniz's view, the essence of a thing is fundamentally the real possibilities of that thing. | |
| From: report of Gottfried Leibniz (works [1690]) by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 4.3.3 | |
| A reaction: Note that the essences are individual. On the whole I would prefer Leibniz in his own words, but this is too good to lose (..but see Idea 12981). It is the aspect of Leibniz that fits perfectly with modern scientific essentialism. |
| 12701 | Leibniz moved from individuation by whole entity to individuation by substantial form [Leibniz, by Garber] |
| Full Idea: By 1680 Leibniz had clearly abandoned the 'whole entity' conception of individuation, for a conception grounded in substantial form alone. | |
| From: report of Gottfried Leibniz (works [1690]) by Daniel Garber - Leibniz:Body,Substance,Monad 2 | |
| A reaction: In other words, Leibniz became more of an Aristotelian, and more of an essentialist. |
| 13105 | The laws-of-the-series plays a haecceitist role [Leibniz, by Cover/O'Leary-Hawthorne] |
| Full Idea: Leibniz takes the laws-of-the-series to play a haecceitistic role. | |
| From: report of Gottfried Leibniz (works [1690]) by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 7.5 | |
| A reaction: Idea 13092 for law-in-the-series. He thinks that a law-in-a-series is unique to a substance, and so can individuate it. That is a pretty good proposal, if anything is going to do the job. Perhaps I do believe in haecceities, as unique bundles of powers? |
| 16513 | Identity of a substance is the law of its persistence [Leibniz] |
| Full Idea: For there to be a certain persisting law which involves the future states of that which we conceive as one and the same continuant, this is what I say constitute's a substance's identity. | |
| From: Gottfried Leibniz (works [1690], G II:264), quoted by David Wiggins - Sameness and Substance 3.1 | |
| A reaction: This is a key remark for those who thing 'persistence conditions' are basic to metaphysics. I'm not so sure. |
| 12035 | Leibniz bases pure primitive entities on conjunctions of qualitative properties [Leibniz, by Adams,RM] |
| Full Idea: Leibniz is committed with apparent consistency to both a purely qualitative character of all thisnesses, and to primitiveness of individual identity. He regards thisnesses as conjunctions of simpler, logically independent suchnesses. | |
| From: report of Gottfried Leibniz (works [1690]) by Robert Merrihew Adams - Primitive Thisness and Primitive Identity 5 | |
| A reaction: Hence Leibniz is held to say that all of the qualitative properties are 'essential' to the object, since all of them are needed to constitute its identity. Hence absolutely nothing about an object, even an electron, could be different, which is daft. |
| 24058 | The substance is the cause of a thing's being [Aristotle] |
| Full Idea: The cause of its being for everything is its substance. | |
| From: Aristotle (De Anima [c.329 BCE], 415b12) | |
| A reaction: It sounds as if 'substance' here means essence. We no longer see the cause of something's being as intrinsic to the thing. Only previous causes produce things. The 'form' must be the intrinsic cause of being. |
| 7561 | Substances are essentially active [Leibniz, by Jolley] |
| Full Idea: For Leibniz, it is the very essence of substances to be sources of activity. | |
| From: report of Gottfried Leibniz (works [1690]) by Nicholas Jolley - Leibniz Ch.2 | |
| A reaction: This makes the views of Leibniz sympathetic to modern essentialism (of which I am a fan), because it places active power at the centre of what it is to exist, rather than action being imposed on matter which is otherwise passive. |
| 13091 | Leibnizian substances add concept, law, force, form and soul [Leibniz, by Cover/O'Leary-Hawthorne] |
| Full Idea: To the traditional idea of substance (independent, subjects of predication, active, persistent) Leibniz adds, distinctively, complete individual concept, law-of-the-series, active force, form and soul or entelechy. | |
| From: report of Gottfried Leibniz (works [1690]) by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 6.1.1 | |
| A reaction: 'Form' seems to be Aristotelian, and 'soul' seems ridiculous. I don't think the 'complete concept' is much help. However, the 'law-in-the-series' is very interesting (Idea 13079), if employed sensibly, and 'active force' is spot-on. Powers define reality. |
| 24055 | Matter is potential, form is actual [Aristotle] |
| Full Idea: Matter is potentiality, whereas form is actuality. | |
| From: Aristotle (De Anima [c.329 BCE], 412a09) | |
| A reaction: Plato said mud has no Form. What did Aristotle think of that? I only ask because to me mud looks like unformed actuality. |
| 24040 | Scientists explain anger by the matter, dialecticians by the form and the account [Aristotle] |
| Full Idea: For a dialectician anger is a desire for retaliation or something like that, where for a natural scientist it is a boiling of the blood and hoot stuff around the heart. The scientist gives the matter, where the dialectician give the form and the account. | |
| From: Aristotle (De Anima [c.329 BCE], 403a30) | |
| A reaction: A nice illumination of hylomorphism. Notice that the dialectician also give the account [logos]. |
| 12715 | Leibniz strengthened hylomorphism by connecting it to force in physics [Leibniz, by Garber] |
| Full Idea: A standard criticism of the scholastic notions of matter and form is that they are obscure and unintelligible. But in Leibniz's system they are connected directly with notions of active and passive force that play an intelligible roles in his physics. | |
| From: report of Gottfried Leibniz (works [1690]) by Daniel Garber - Leibniz:Body,Substance,Monad 4 | |
| A reaction: This seems to me to be very appealing. Aristotle was clearly on the right lines, but just ran out of things to say, once he had pointed in the right direction. Maybe 'fields' and 'strings' can fill out the Aristotelian conception of form. |
| 11878 | Leibniz's view (that all properties are essential) is extreme essentialism, not its denial [Leibniz, by Mackie,P] |
| Full Idea: The view standardly attributed to Leibniz, that makes all an individual's properties essential to it should be regarded as an extreme version of essentialism, not a denial of essentialism. | |
| From: report of Gottfried Leibniz (works [1690]) by Penelope Mackie - How Things Might Have Been 1.1 | |
| A reaction: Wiggins disagrees, saying that Leibniz was not an essentialist, which is an interesting topic of research for those who are interested. I would take Leibniz to be not an essentialist, on that basis, as essentialism makes a distinction. See Quine on that. |
| 11862 | Leibniz was not an essentialist [Leibniz, by Wiggins] |
| Full Idea: Leibniz was not an essentialist. | |
| From: report of Gottfried Leibniz (works [1690]) by David Wiggins - Sameness and Substance Renewed 4.2 n4 | |
| A reaction: Assuming this is right, it is rather helpful, because you can read mountains of Leibniz without ever being quite sure. Mackie says he IS an extreme essentialist, treating all properties as essential. Wiggins makes more sense there. |
| 4640 | If identity is based on 'true of X' instead of 'property of X' we get the Masked Man fallacy ('I know X but not Y') [Baggini /Fosl, by PG] |
| Full Idea: The Masked Man fallacy is when Leibniz's Law is taken as 'X and Y are identical if what is true of X is true of Y' (rather than being about properties). Then 'I know X' but 'I don't know Y' (e.g. my friend wearing a mask) would make X and Y non-identical. | |
| From: report of J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §3.17) by PG - Db (ideas) | |
| A reaction: As the book goes on to explain, Descartes is guilty of this when arguing that I necessarily know my mind but not my body, so they are different. Seems to me that Kripke falls into the same trap. |
| 4647 | 'I have the same car as you' is fine; 'I have the same fiancée as you' is not so good [Baggini /Fosl] |
| Full Idea: If you found that I had the same car as you, I don't suppose you would care, but if you found I had the same fiancée as you, you might not be so happy. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §4.17) | |
| A reaction: A very nice illustration of the ambiguity of "same", and hence of identity. 'I had the same thought as you'. 'I have the same DNA as you'. |
| 16504 | Two eggs can't be identical, because the same truths can't apply to both of them [Leibniz] |
| Full Idea: It isn't possible to have two particulars that are similar in all respects - for example two eggs - for it is necessary that some things can be said about one of them that cannot be said about the other, else they could be substituted for one another. | |
| From: Gottfried Leibniz (works [1690]), quoted by David Wiggins - Sameness and Substance 2.2 | |
| A reaction: [from a 'fragment' for which Wiggins gives a reference] This quotation doesn't rest the distinctness of the eggs on some intrinsic difference, but on the fact that we can say different things about the two eggs. |
| 4639 | Leibniz's Law is about the properties of objects; the Identity of Indiscernibles is about perception of objects [Baggini /Fosl] |
| Full Idea: Leibniz's Law ('if identical, must have same properties') defines identity according to the properties possessed by the object itself, but the Identity of Indiscernibles defines identity in terms of how things are conceived or grasped by the mind. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §3.16) | |
| A reaction: This is the heart of the problem of identity. We realists must fight for Leibniz's Law, and escort the Identity of Indiscernibles to the door. |
| 8650 | Things are the same if one can be substituted for the other without loss of truth [Leibniz] |
| Full Idea: Leibniz's definition is as follows: Things are the same as each other, of which one can be substituted for the other without loss of truth ('salva veritate'). | |
| From: Gottfried Leibniz (works [1690]), quoted by Gottlob Frege - Grundlagen der Arithmetik (Foundations) §65 | |
| A reaction: Frege doesn't give a reference. (Anyone know it?). This famous definition is impressive, but has problems when the items being substituted appear in contexts of belief. 'Oedipus believes Jocasta (his mother!) would make a good wife'. |
| 13828 | Necessary truths are those provable from identities by pure logic in finite steps [Leibniz, by Hacking] |
| Full Idea: Leibniz argued that the necessary truths are just those which can be proved from identities by pure logic in a finite number of steps. ...[232] this claim is vindicated by Gentzen's sequent calculus. | |
| From: report of Gottfried Leibniz (works [1690]) by Ian Hacking - What is Logic? §01 | |
| A reaction: This seems an odd idea, as if there were no necessary truths other than those for which a proof could be constructed. Sounds like intuitionism. |
| 4646 | Is 'events have causes' analytic a priori, synthetic a posteriori, or synthetic a priori? [Baggini /Fosl] |
| Full Idea: Of the proposition that "all experienced events have causes", Descartes says this is analytic a priori, Hume says it is synthetic a posteriori, and Kant says it is synthetic a priori. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §4.01) | |
| A reaction: I am not sympathetic to Hume on this (though most people think he is right). I prefer the Kantian view, but he makes a very large claim. Something has to be intuitive. |
| 13084 | How can things be incompatible, if all positive terms seem to be compatible? [Leibniz] |
| Full Idea: It is yet unknown to me what is the reason of the incompossibility of things, or how it is that different essences can be opposed to each other, seeing that all purely positive terms seem to be compatible. | |
| From: Gottfried Leibniz (works [1690], G VII:194), quoted by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 3.4.4 | |
| A reaction: Since 'heavy' seems straightforwardly opposed to 'light', we would have to ask what he means by 'positive'. The suspicion is that all things are compossible by definition, so it is not surprising that impossibilities are a bit puzzling. |
| 4307 | A reason must be given why contingent beings should exist rather than not exist [Leibniz] |
| Full Idea: A reason must be given why contingent beings should exist rather than not exist. | |
| From: Gottfried Leibniz (works [1690]) | |
| A reaction: Spinoza rejects all contingency, but this seems an interesting support for it, even though we may need a reason for something where God does not because it is self-evident. |
| 15883 | Leibniz narrows down God's options to one, by non-contradiction, sufficient reason, indiscernibles, compossibility [Leibniz, by Harré] |
| Full Idea: Leibniz sets up increasingly stringent conditions possible worlds must meet. The weakest is non-contradiction, for truths of reason; then sufficient reason, for rational worlds; then identity of indiscernibles, for duplicates; then compossibility. | |
| From: report of Gottfried Leibniz (works [1690]) by Rom Harré - Laws of Nature 4 | |
| A reaction: [my summary of a very nice two pages by Harré] God is the source of the principles which do the narrowing down. |
| 18822 | Each monad expresses all its compatible monads; a possible world is the resulting equivalence class [Leibniz, by Rumfitt] |
| Full Idea: Leibniz argued that each monad mirrors or expresses every monad with which it is compossible. Hence compossibility is an equivalence relation among monads; possible worlds may then be identified as the corresponding equivalence classes. | |
| From: report of Gottfried Leibniz (works [1690]) by Ian Rumfitt - The Boundary Stones of Thought 6.1 | |
| A reaction: [Rumfitt cites Benson Mates 1986:IV.1 for this claim] There is an analogous world of all the human minds that are in communication with one another - something like a 'culture'. |
| 7837 | Leibniz proposed possible worlds, because they might be evil, where God would not create evil things [Leibniz, by Stewart,M] |
| Full Idea: In his early writings the principle of sufficient reason made it difficult for Leibniz to conceive of possible things;...raising this to possible worlds means God does not choose things that are evil, but chooses a world which must have evil in it. | |
| From: report of Gottfried Leibniz (works [1690]) by Matthew Stewart - The Courtier and the Heretic Ch.14 | |
| A reaction: Where we think of possible worlds as explanations for conditional and counterfactual truths (I take it), Leibniz developed the original idea as part of his huge effort to achieve a consistent theodicy. |
| 13080 | Leibniz has a counterpart view of de re counterfactuals [Leibniz, by Cover/O'Leary-Hawthorne] |
| Full Idea: When Leibniz has the grounds of de re counterfactuals in mind, a counterpart picture, we have argued, is at work. | |
| From: report of Gottfried Leibniz (works [1690]) by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 3.2.2 | |
| A reaction: If Leibniz were a 'superessentialist', then individuals would be totally worldbound (because their relations would be essential). Cover/Hawthorne argue that he is just a 'strong' essentialist, allowing possible counterparts. Quite persuasive. |
| 19332 | For Leibniz, divine understanding grasps every conceivable possibility [Leibniz, by Perkins] |
| Full Idea: For Leibniz, what is this understanding which God has? What does it contain? All possibilities in all possible combinations, that is, everything which can be conceived. | |
| From: report of Gottfried Leibniz (works [1690]) by Franklin Perkins - Leibniz: Guide for the Perplexed 2.III | |
| A reaction: I like this, because it strikes me as essential that understanding should embrace possibilities as well as actualities. Perkins points out that the possibilities are restricted by an awareness of the limitations imposed by combination. |
| 5509 | Leibniz said dualism of mind and body is illusion, and there is only mind [Leibniz, by Martin/Barresi] |
| Full Idea: Leibniz held that dualism of mind and body is an illusion and that both are really the same thing, and that this thing is mind. | |
| From: report of Gottfried Leibniz (works [1690]) by R Martin / J Barresi - Introduction to 'Personal Identity' p.22 | |
| A reaction: I am puzzled by this, as Leibniz is famous for the view that mind and body are parallel. See idea 5038, and also 2109 and 2596. Monads are, of course, entirely mental, and are the building blocks of reality. Clearly I (and you) must read more Leibniz. |
| 7568 | Leibniz is an idealist insofar as the basic components of his universe are all mental [Leibniz, by Jolley] |
| Full Idea: To say that Leibniz is an idealist is to say that simple substances, the basic building-blocks of the universe, are all mental or at least quasi-mental in nature | |
| From: report of Gottfried Leibniz (works [1690]) by Nicholas Jolley - Leibniz Ch.3 | |
| A reaction: This is a bit different from the Berkelian type of idealism, which says that reality consists entirely of events within thinking minds. Is a monad the thinker or the thought? |
| 4645 | 'A priori' does not concern how you learn a proposition, but how you show whether it is true or false [Baggini /Fosl] |
| Full Idea: What makes something a priori is not the means by which it came to be known, but the means by which it can be shown to be true or false. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §4.01) | |
| A reaction: Helpful. Kripke in particular has labelled the notion as an epistemological one, but that does imply a method of acquiring it. Clearly I can learn an a priori truth by reading it the newspaper. |
| 5051 | The intellect has potential to think, like a tablet on which nothing has yet been written [Aristotle] |
| Full Idea: The intellect is in a way potentially the object of thought, but nothing in actuality before it thinks, and the potentiality is like that of the tablet on which there is nothing actually written. | |
| From: Aristotle (De Anima [c.329 BCE], 429b31) | |
| A reaction: This passage is referred to by Leibniz, and is the origin of the concept of the 'tabula rasa'. Aristotle need not be denying innate ideas, but merely describing the phenomenology of the moment before a train of thought begins. |
| 16723 | Perception of sensible objects is virtually never wrong [Aristotle] |
| Full Idea: Perception of the special objects of sense is never in error or admits the least possible amount of falsehood. | |
| From: Aristotle (De Anima [c.329 BCE], 428b19) | |
| A reaction: This is, surprisingly, the view which was raised and largely rejected in 'Theaetetus'. It became a doctrine of Epicureanism, and seems to make Aristotle a thoroughgoing empiricist, though that is not so clear elsewhere. I think Aristotle is right. |
| 1724 | Perception necessitates pleasure and pain, which necessitates appetite [Aristotle] |
| Full Idea: Where there is perception there is also pleasure and pain, and where there are these, of necessity also appetite. | |
| From: Aristotle (De Anima [c.329 BCE], 413b23) |
| 1730 | Why do we have many senses, and not just one? [Aristotle] |
| Full Idea: A possible line of inquiry would be into the question for what purpose we have many senses and not just one. | |
| From: Aristotle (De Anima [c.329 BCE], 425b04) |
| 17711 | Our minds take on the form of what is being perceived [Aristotle, by Mares] |
| Full Idea: Aristotle famously holds that in perception our minds take on the form of what is being perceived. | |
| From: report of Aristotle (De Anima [c.329 BCE]) by Edwin D. Mares - A Priori 08.2 | |
| A reaction: [References in Aristotle needed here...] |
| 1725 | Why can't we sense the senses? And why do senses need stimuli? [Aristotle] |
| Full Idea: Why is there not also a sense of the senses themselves? And why don't the senses produce sensation without external bodies, since they contain elements? | |
| From: Aristotle (De Anima [c.329 BCE], 417a03) |
| 1732 | Sense organs aren't the end of sensation, or they would know what does the sensing [Aristotle] |
| Full Idea: Flesh is not the ultimate sense-organ. To suppose that it is requires the supposition that on contact with the object the sense-organ itself discerns what is doing the discerning. | |
| From: Aristotle (De Anima [c.329 BCE], 426b16) |
| 1728 | Many objects of sensation are common to all the senses [Aristotle] |
| Full Idea: Common sense-objects are movement, rest, number, shape and size, which are not special to any one sense, but common to all. | |
| From: Aristotle (De Anima [c.329 BCE], 418a18) |
| 1727 | Some objects of sensation are unique to one sense, where deception is impossible [Aristotle] |
| Full Idea: Now I call that sense-object 'special' that does not admit of being perceived by another sense and about which it is impossible to be deceived. | |
| From: Aristotle (De Anima [c.329 BCE], 418a15) |
| 1734 | In moral thought images are essential, to be pursued or avoided [Aristotle] |
| Full Idea: In the thinking soul, images play the part of percepts, and the assertion or negation of good or bad is invariably accompanied by avoidance or pursuit, which is the reason for the soul's never thinking without an image. | |
| From: Aristotle (De Anima [c.329 BCE], 431a15) |
| 1726 | We may think when we wish, but not perceive, because universals are within the mind [Aristotle] |
| Full Idea: Perception is of particular things, but knowledge is of universals, which are in a way in the soul itself. Thus a man may think whenever he wishes, but not perceive. | |
| From: Aristotle (De Anima [c.329 BCE], 417b22) |
| 4582 | Basic beliefs are self-evident, or sensual, or intuitive, or revealed, or guaranteed [Baggini /Fosl] |
| Full Idea: Sentence are held to be basic because they are self-evident or 'cataleptic' (Stoics), or rooted in sense data (positivists), or grasped by intuition (Platonists), or revealed by God, or grasped by faculties certified by God (Descartes). | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §1.01) | |
| A reaction: These are a bit blurred. Isn't intuition self-evident? Isn't divine guarantee a type of revelation? How about reason, experience or authority? |
| 16647 | Demonstration starts from a definition of essence, so we can derive (or conjecture about) the properties [Aristotle] |
| Full Idea: In demonstration a definition of the essence is required as starting point, so that definitions which do not enable us to discover the derived properties, or which fail to facilitate even a conjecture about them, must obviously be dialectical and futile. | |
| From: Aristotle (De Anima [c.329 BCE], 402b25) | |
| A reaction: Interesting to see 'dialectical' used as a term of abuse! Illuminating. For scientific essentialism, then, demonstration is filling out the whole story once the essence has been inferred. It is circular, because essence is inferred from accidents. |
| 24048 | Demonstrations move from starting-points to deduced conclusions [Aristotle] |
| Full Idea: Demonstrations are both from a starting-point and have a sort of end, namely the deduction or the conclusion. | |
| From: Aristotle (De Anima [c.329 BCE], 407a25) | |
| A reaction: A starting point has to be a first principle [arché]. It has been observed that Aristotle explains demonstration very carefully, but rarely does it in his writings. |
| 4644 | A proposition such as 'some swans are purple' cannot be falsified, only verified [Baggini /Fosl] |
| Full Idea: The problem with falsification is that it fails to work with logically particular claims such as 'some swans are purple'. Examining a million swans and finding no purple ones does not falsify the claim, as there might still be a purple swan out there. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §3.29) | |
| A reaction: Isn't it beautiful how unease about a theory (Popper's) slowly crystallises into an incredibly simple and devastating point? Maybe 'some swans are purple' isn't science unless there is a good reason to propose it? |
| 4584 | The problem of induction is how to justify our belief in the uniformity of nature [Baggini /Fosl] |
| Full Idea: At its simplest, the problem of induction can be boiled down to the problem of justifying our belief in the uniformity of nature. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §1.03) | |
| A reaction: An easy solution to the problem of induction: we treat the uniformity of nature as axiomatic, and then induction is all reasoning which is based on that axiom. The axiom is a working hypothesis, which may begin to appear false. Anomalies are hard. |
| 4583 | How can an argument be good induction, but poor deduction? [Baggini /Fosl] |
| Full Idea: The problem of induction is the problem of how an argument can be good reasoning as induction but poor reasoning as deduction. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §1.03) | |
| A reaction: Nicely put, and a good defence of Hume against the charge that he has just muddled induction and deduction. All reasoning, we insist, should be consistent, or it isn't reasoning. |
| 16646 | To understand a triangle summing to two right angles, we need to know the essence of a line [Aristotle] |
| Full Idea: In mathematics it is useful for the understanding of the property of the equality of the interior angles of a triangle to two right angles to know the essential nature of the straight and the curved or of the line and the plane. | |
| From: Aristotle (De Anima [c.329 BCE], 402b18) | |
| A reaction: Although Aristotle was cautious about this, he clearly endorses here the idea that essences play an explanatory role in geometry. The caution is in the word 'useful', rather than 'vital'. How else can we arrive at this result, though? |
| 13092 | The essence of substance is the law of its changes, as in the series of numbers [Leibniz] |
| Full Idea: The essence of substance consists in ...the law of the sequence of changes, as in the nature of the series in numbers. | |
| From: Gottfried Leibniz (works [1690], A 6.3.326), quoted by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 6.1.2 | |
| A reaction: Thus we might say, in this spirit, that the essence of number is the successor operation, as defined by Dedekind and Peano (and perhaps their amenability to inductive proof). I like this. Metaphysicians rule - they penetrate the heart of nature. |
| 4634 | Abduction aims at simplicity, testability, coherence and comprehensiveness [Baggini /Fosl] |
| Full Idea: There are some 'principles of selection' in abduction: 1) prefer simple explanations, 2) prefer coherent explanations (consistent with what is already held true), 3) prefer theories that make testable predictions, and 4) be comprehensive in scope. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §2.01) | |
| A reaction: Note that these are desirable, but not necessary (pace Ockham and Ayer). I cannot think of anything to add to the list, so I will adopt it. Abduction is the key to rationality. |
| 4637 | To see if an explanation is the best, it is necessary to investigate the alternative explanations [Baggini /Fosl] |
| Full Idea: The only way to be sure we have the best explanation is to investigate the alternatives and see if they are any better. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §3.01) | |
| A reaction: Unavoidable! Since I love 'best explanation', I now seem to be committed to investigation every mad theory that comes up, just in case it is better. I hope I am allowed to reject after a very quick sniff. |
| 1714 | Mind involves movement, perception, incorporeality [Aristotle] |
| Full Idea: The soul seems to be universally defined by three features, so to speak, the production of movement, perception and incorporeality. | |
| From: Aristotle (De Anima [c.329 BCE], 405b12) | |
| A reaction: 'Incorporeality' begs the question, but its appearance is a phenomenon that needs explaining. 'Movement' is an interesting Greek view. Nowadays we would presumably added intentional states, and the contents and meaning of thoughts. No 'reason'? |
| 5507 | Aristotle led to the view that there are several souls, all somewhat physical [Aristotle, by Martin/Barresi] |
| Full Idea: On the later views inspired by Aristotle's 'De Anima' there was no longer just one soul, but several, and each of them had a great deal in common with the body. | |
| From: report of Aristotle (De Anima [c.329 BCE]) by R Martin / J Barresi - Introduction to 'Personal Identity' p.17 | |
| A reaction: Is this based on the faculties of sophia, episteme, nous, techne and phronesis, or is it based on the vegetative, appetitive and rational parts? The latter, I presume. Not so interesting, not so modular. |
| 24051 | Soul is seen as what moves, or what is least physical, or a combination of elements [Aristotle] |
| Full Idea: Three ways have been handed down in which people define the soul: what is most capable of moving things, since it moves itself; or a body which is the most fine-grained and least corporeal; or that it is composed of the elements. | |
| From: Aristotle (De Anima [c.329 BCE], 409b19) | |
| A reaction: A nice example of Aristotle beginning an investigation by idenfying the main explanations which have been 'handed down' from previous generations. These three aren't really in competition, and might all be true. |
| 12086 | Psuché is the form and actuality of a body which potentially has life [Aristotle] |
| Full Idea: Soul is substance as the form of a natural body which potentially has life, and since this substance is actuality, soul will be the actuality of such a body. | |
| From: Aristotle (De Anima [c.329 BCE], 412a20) | |
| A reaction: To understand what Aristotle means by 'form' you must, I'm afraid, read the 'Metaphysics'. Form isn't shape, but rather the essence which bestows the individual identity on the thing. 'Psuche is the essence of man' might be a better slogan. |
| 16754 | The soul is the cause or source of movement, the essence of body, and its end [Aristotle] |
| Full Idea: The soul is the cause [aitia] of its body alike in three senses which we explicitly recognise. It is (a) the source or origin of movement, it is (b) the end, and it is (c) the essence of the whole living body. | |
| From: Aristotle (De Anima [c.329 BCE], 415b09) | |
| A reaction: 'Aitia' also means explanation, so these are three ways to explain a human being, by what it does, why what it is for, and by what it intrinsically is. Activity, purpose and nature. |
| 24046 | Understanding is impossible, if it involves the understanding having parts [Aristotle] |
| Full Idea: How could a spatial understanding understand anything? Wiil it do so with parts, seen as magnitudes or as points? If it is points, the understanding will never get through them all. If magnitudes, it will understand things an unlimited number of times. | |
| From: Aristotle (De Anima [c.329 BCE], 407a09) | |
| A reaction: This seems to be a strong commitment to the idea that the mind is not physical because it is necessarily non-spatial. |
| 1717 | If the soul is composed of many physical parts, it can't be a true unity [Aristotle] |
| Full Idea: If the soul is composed of parts of the body, or the harmony of the elements composing the body, there will be many souls, and everywhere in the body. | |
| From: Aristotle (De Anima [c.329 BCE], 408a15) | |
| A reaction: We will ignore "everywhere in the body", but the rest seems to me exactly right. The idea of the unity of the soul is an understandable and convenient assumption, but it leads to all sorts of confusion. A crowd remains unified if half its members leave. |
| 24053 | If a soul have parts, what unites them? [Aristotle] |
| Full Idea: What is it that holds the soul together, if it by nature has parts? For surely it cannot be the body. For it seems on the contrary that it is rather the soul that holds the body together? | |
| From: Aristotle (De Anima [c.329 BCE], 411b05) | |
| A reaction: This is the hylomorphic view of a human, that the soul is the form that give unity to the matter. To do the job, presumably the form or soul need an intrinsic unity of its own, and hence cannot have parts. Apart from the need for unifying glue. |
| 1721 | What unifies the soul would have to be a super-soul, which seems absurd [Aristotle] |
| Full Idea: If soul has parts, what holds them together? Not body, because that is united by soul. If a thing unifies the soul, then THAT is the soul (unless it too has parts, which would lead to an infinite regress). Best to say the soul is a unity. | |
| From: Aristotle (De Anima [c.329 BCE], 411b10) | |
| A reaction: You don't need a 'thing' to unify something (like a crowd). I say the body holds the soul together, not physically, but because the body's value permeates thought. The body is the focused interest of the soul, like parents kept together by their child. |
| 1735 | In a way the soul is everything which exists, through its perceptions and thoughts [Aristotle] |
| Full Idea: The soul is in a way all the things that exist, for all the things that exist are objects either of perception or of thought. | |
| From: Aristotle (De Anima [c.329 BCE], 431b20) | |
| A reaction: Sounds very like Berkeley's empirical version of idealism. It also seems to imply modern externalist (anti-individualist) understandings of the mind (which strike me as false). |
| 19354 | Leibniz introduced the idea of degrees of consciousness, essential for his monads [Leibniz, by Perkins] |
| Full Idea: The designation of degrees of conscious awareness is one of Leibniz's most significant innovations, and it is fundamental to almost every aspect of his account of monads. | |
| From: report of Gottfried Leibniz (works [1690]) by Franklin Perkins - Leibniz: Guide for the Perplexed 4.I | |
| A reaction: A very important development, which seems to have been ignored by philosophers for three hundred years, since they usually treat consciousness as all-or-nothing. Introspection makes degrees obvious, and I suspect sparrows are down the scale. |
| 24061 | If we divide the mind up according to its capacities, there are a lot of them [Aristotle] |
| Full Idea: For those who divide the soul into parts, and divide and separate them in accord with their capacities, the parts turn out to be very many. | |
| From: Aristotle (De Anima [c.329 BCE], 433a32) | |
| A reaction: I accept the warning. The capacities which interest me are those which seem to generate our basic ontology, but if the capacities become fine-grained, they are legion. |
| 24062 | Self-moving animals must have desires, and that entails having imagination [Aristotle] |
| Full Idea: If an animal has a desiring part, it is capable of moving itself. A desiring part, however, cannot exist without an imagination, and all imagination is either rationally calculative or perceptual. Hence in the latter the other animals also have a share. | |
| From: Aristotle (De Anima [c.329 BCE], 433b27) | |
| A reaction: Maybe if you asked people whether other animals are imaginative they would say no, but this argument is strong support for the positive view. |
| 7841 | We think we are free because the causes of the will are unknown; determinism is a false problem [Leibniz] |
| Full Idea: The will has its causes, but since we are ignorant of them, we believe ourselves independent. It is this chimera of imaginary independence which revolts us against determinism, and which brings us to believe there are difficulties where there are none. | |
| From: Gottfried Leibniz (works [1690]), quoted by Matthew Stewart - The Courtier and the Heretic Ch.16 | |
| A reaction: It seems that in his notebooks Leibniz was actually a (Spinozan) determinist. So he should have been, given his view that we live in the best of all possible worlds, and his claim that mind and brain run like two clocks. (Ideas 2114 and 2596) |
| 1710 | Emotion involves the body, thinking uses the mind, imagination hovers between them [Aristotle] |
| Full Idea: Most affections (like anger) seem to involve the body, but thinking seems distinctive of the soul. But if this requires imagination, it too involves the body. Only pure mental activity would prove the separation of the two. | |
| From: Aristotle (De Anima [c.329 BCE], 403a08-) | |
| A reaction: What an observant man! Modern neuroscience is bringing out the fact that emotion is central to all mental life. We can't recognise faces without it. I say imagination is essential to pure reason, and that seems emotional too. Reason is physical. |
| 24056 | The soul (or parts of it) is not separable from the body [Aristotle] |
| Full Idea: That the soul is not separable from the body - or that certain parts of it are not, if it naturally has parts - is quite clear. | |
| From: Aristotle (De Anima [c.329 BCE], 413a04) | |
| A reaction: This doesn't make him a physicalist. I've seen him described in modern terms as a functionalist, but that makes the mind abstract and the body concrete. Perhaps he is an 'Integrationist' (as Descartes might be in his 'pilot' passage). |
| 24039 | All the emotions seem to involve the body, simultaneously with the feeling [Aristotle] |
| Full Idea: The affections of the soul - spiritedness, fear, pity, confidence, joy, loving, hating - would all seem to involve the body, since at the same time as these the body is affected in a certain way. | |
| From: Aristotle (De Anima [c.329 BCE], 403a16) | |
| A reaction: Aristotle was not a physicalist, but this resembles the pilot-in-the-ship passage in Descartes, accepting the very close links. |
| 5510 | Leibniz has a panpsychist view that physical points are spiritual [Leibniz, by Martin/Barresi] |
| Full Idea: In Leibniz's panpsychism, the so-called 'physical' points are souls or spiritual 'monads'. | |
| From: report of Gottfried Leibniz (works [1690]) by R Martin / J Barresi - Introduction to 'Personal Identity' p.23 | |
| A reaction: I'm not convinced that 'panpsychism' is the right description for Leibniz's theory of monads. I take panpsychism to be either a dualist or a dual aspect (or property dualism) view. Leibniz seems to believe there is strictly one substance. |
| 7564 | Occasionalism give a false view of natural laws, miracles, and substances [Leibniz, by Jolley] |
| Full Idea: Leibniz's three objections to occasionalism are: it disturbs the concept of laws of nature used in physics; it introduces perpetual miracles; and it doesn't recognise activity of substances (leading to the Spinozan heresy that God is the only substance). | |
| From: report of Gottfried Leibniz (works [1690]) by Nicholas Jolley - Leibniz Ch.2 | |
| A reaction: I wonder what would happen if, within the viewpoint of occasionalism, God suddenly packed up and abandoned his job? Presumably the world wouldn't disappear, so there would still be substances, but passive ones, in chaos. |
| 24049 | Thinkers place the soul within the body, but never explain how they are attached [Aristotle] |
| Full Idea: There is another absurdity which follows, …since they attach the soul to a body, and place it in the body, without further determining the cause due to which this attachment comes about. …Yet this seems necessary, because this association produces action. | |
| From: Aristotle (De Anima [c.329 BCE], 407b14) | |
| A reaction: A clear statement of the interaction objection to full substance dualism. Critics say that dualists have to invoke a 'miracle' at this point. |
| 1514 | Early thinkers concentrate on the soul but ignore the body, as if it didn't matter what body received the soul [Aristotle] |
| Full Idea: Early thinkers try only to describe the soul, but they fail to go into any kind of detail about the body which is to receive the soul, as if it were possible (as it is in the Pythagorean tales) for just any old soul to be clothed in just any old body. | |
| From: Aristotle (De Anima [c.329 BCE], 407b20) | |
| A reaction: Precisely. Anyone who seriously believes that a human mind can be reincarnated in a flea needs their mind examined. Actually they need their brain examined, but that probably wouldn't impress them. I can, of course, imagine moving into a flea. |
| 24050 | If soul is separate from body, why does it die when the body dies? [Aristotle] |
| Full Idea: If the soul is something distinct from the mixture, why then are the being for flesh and for the other parts of the animal destroyed at the same time? | |
| From: Aristotle (De Anima [c.329 BCE], 408a25) | |
| A reaction: An obvious response to this reasonable question is to say that we see the body die, but not the soul, so the soul doesn't die. The problem is then to find some evidence for the soul's continued existence. |
| 1718 | Does the mind think or pity, or does the whole man do these things? [Aristotle] |
| Full Idea: Perhaps it would be better not to say that the soul pities or learns or thinks, but that the man does in virtue of the soul. | |
| From: Aristotle (De Anima [c.329 BCE], 408b12) | |
| A reaction: This can be seen as incipient behaviourism in Aristotle's view. It echoes the functionalist view that what matters is not what the mind is, or is made of, but what it does. |
| 2683 | Aristotle has a problem fitting his separate reason into the soul, which is said to be the form of the body [Ackrill on Aristotle] |
| Full Idea: In 'De Anima' Aristotle cannot fit his account of separable reason - which is not the form of a body - into his general theory that the soul is the form of the body. | |
| From: comment on Aristotle (De Anima [c.329 BCE]) by J.L. Ackrill - Aristotle on Eudaimonia p.33 | |
| A reaction: A penetrating observation. Possibly the biggest challenge for a modern physicalist is to give a reductive account of 'pure' reason, in terms of brain events or brain functions. |
| 13275 | The soul and the body are inseparable, like the imprint in some wax [Aristotle] |
| Full Idea: We should not enquire whether the soul and the body are one thing, any more than whether the wax and its imprint are, or in general whether the matter of each thing is one with that of which it is the matter. | |
| From: Aristotle (De Anima [c.329 BCE], 412b06) | |
| A reaction: This is his hylomorphist view of objects, so that the soul is the 'form' which bestows identity (and power) on the matter of which it is made. This remark is thoroughly physicalist. |
| 1733 | Thinking is not perceiving, but takes the form of imagination and speculation [Aristotle] |
| Full Idea: Thinking, then, is something other than perceiving, and its two kinds are held to be imagination and supposition. | |
| From: Aristotle (De Anima [c.329 BCE], 427b28) |
| 4629 | Consistency is the cornerstone of rationality [Baggini /Fosl] |
| Full Idea: Consistency is the cornerstone of rationality. | |
| From: J Baggini / PS Fosl (The Philosopher's Toolkit [2003], §1.06) | |
| A reaction: This is right, and is a cornerstone of Kant's approach to ethics. Rational beings must follow principles - in order to be consistent in their behaviour. 'Consistent' now requires a definition…. |
| 23307 | Aristotle makes belief a part of reason, but sees desires as separate [Aristotle, by Sorabji] |
| Full Idea: Aristotle insists [against Plato] that desires, even rational desires, are a capacity distinct from reason, as is perception. Belief is included within reason. And he sometimes distinguishes steps of reasoning from insight. | |
| From: report of Aristotle (De Anima [c.329 BCE], 428-432) by Richard Sorabji - Rationality 'Shifting' | |
| A reaction: So the standard picture of desire as permanently in conflict with reason comes from Aristotle. Maybe Plato is right on that one (though he doesn't say much about it). Since objectivity needs knowledge, reason does need belief. |
| 19372 | Concepts are ordered, and show eternal possibilities, deriving from God [Leibniz, by Arthur,R] |
| Full Idea: Leibniz understood concepts as corresponding to eternal possibilities, with both concepts and their ordering having their foundation in the divine mind. | |
| From: report of Gottfried Leibniz (works [1690]) by Richard T.W. Arthur - Leibniz 2 'Nominalism' | |
| A reaction: It is is no longer the fashion to think of concepts as 'ordered', and yet there is a multitude of dependence relations between them. |
| 13467 | Leibniz was the first modern to focus on sentence-sized units (where empiricists preferred word-size) [Leibniz, by Hart,WD] |
| Full Idea: Leibniz seems to be the first modern philosopher to focus on sentence-sized units that he called propositions. The Empiricists among the moderns focused on word-sized units like ideas. | |
| From: report of Gottfried Leibniz (works [1690]) by William D. Hart - The Evolution of Logic 2 | |
| A reaction: Historically, the sentential logic of the Stoics has a claim to have started this one. I find my initial sympathies to be with the empiricists. |
| 24060 | Self-controlled follow understanding, when it is opposed to desires [Aristotle] |
| Full Idea: Self-controlled people, even when they desire and have an appetite for things, do not do these things for which they have the desire, but instead follow the understanding. | |
| From: Aristotle (De Anima [c.329 BCE], 433a06) | |
| A reaction: If modern discussions would stop talking of 'weakness of will', and talk instead of 'control' and its lack, the whole issue would become clearer. Akrasia is then seen, for example, as an action of the whole person, not of some defective part. |
| 19365 | Limited awareness leads to bad choices, and unconscious awareness makes us choose the bad [Leibniz, by Perkins] |
| Full Idea: For Leibniz, while the limits of our knowledge explain why we sometimes choose things we think are good but which turn out to be bad, the force of minute perceptions explains why we sometimes choose things that we know are bad. | |
| From: report of Gottfried Leibniz (works [1690]) by Franklin Perkins - Leibniz: Guide for the Perplexed 4.IV | |
| A reaction: To be overwhelmed by selfish greed doesn't sound like a 'minute perception'. Leibniz thinks all desires are reactions to perceptions. Observing our degrees of knowledge is an interesting response to the intellectualist view of weakness of will. |
| 8110 | Leibniz identified beauty with intellectual perfection [Leibniz, by Gardner] |
| Full Idea: Leibniz identified beauty with intellectual perfection. | |
| From: report of Gottfried Leibniz (works [1690]) by Sebastian Gardner - Aesthetics 1.2.1 | |
| A reaction: Well he would, wouldn't he? Swots like Leibniz are inclined to value things which only they can fully appreciate. There may be intellectual subject matter in the study of a rose, but I do not believe that it is needed to appreciate the beauty. |
| 7569 | Humans are moral, and capable of reward and punishment, because of memory and self-consciousness [Leibniz, by Jolley] |
| Full Idea: For Leibniz, it is by virtue of possessing memory and self-consciousness that human minds are moral beings, capable of reward and punishment. | |
| From: report of Gottfried Leibniz (works [1690]) by Nicholas Jolley - Leibniz Ch.4 | |
| A reaction: I like this because it makes no mention of free will (though Leibniz struggled to defend free will). I would add meta-thought (the ability to ponder and evaluate our own thinking), which makes a change of mind possible. |
| 4376 | Pleasure and pain are perceptions of things as good or bad [Aristotle] |
| Full Idea: To experience pleasure or pain is to be active with the perceptive mean in relation to good or bad as such. | |
| From: Aristotle (De Anima [c.329 BCE], 431a10) | |
| A reaction: A bizarre view which is interesting, but strikes me as wrong. We are drawn towards pleasure, but judgement can pull us away again, and 'good' is in the judgement, not in the feeling. |
| 7574 | Natural law theory is found in Aquinas, in Leibniz, and at the Nuremberg trials [Leibniz, by Jolley] |
| Full Idea: Leibniz rejects Hobbes's legal positivism in favour of the older natural law theory associated with Aquinas (which says nothing can be a law unless it derives from natural justice). The older view was revived at Nuremberg, to prosecute Nazis. | |
| From: report of Gottfried Leibniz (works [1690]) by Nicholas Jolley - Leibniz Ch.7 | |
| A reaction: This seems to suggest that Hobbes and co were using Ockham's Razor to eliminate morality from the law, but that the Nuremberg situation (and modern trials in The Hague) show that there is a necessity for natural law in international situations. |
| 1740 | Nature does nothing in vain [Aristotle] |
| Full Idea: Nature does nothing in vain. | |
| From: Aristotle (De Anima [c.329 BCE], 434a31) |
| 12728 | Leibniz rejected atoms, because they must be elastic, and hence have parts [Leibniz, by Garber] |
| Full Idea: Leibniz held that there can be no atoms in nature, nothing perfectly solid and hard, since elasticity entails the existence of smaller parts that can move with respect to one another. | |
| From: report of Gottfried Leibniz (works [1690]) by Daniel Garber - Leibniz:Body,Substance,Monad 5 | |
| A reaction: Thus, I suppose, we discover that atoms have mercurial electron shells. Are quarks or electrons elastic? The debate about true atoms is not over, and probably never will be. Leibniz's point is a good one. |
| 19374 | Microscopes and the continuum suggest that matter is endlessly divisible [Leibniz] |
| Full Idea: Micrographers observe qualities of larger things found in smaller things. And if this proceeds to infinity - which is possible since the continuum is divisible to infinity - any atom will be an infinite species, and there will be worlds within worlds. | |
| From: Gottfried Leibniz (works [1690], A VI ii 241) | |
| A reaction: [a work of the 1670s] The microscope had a huge impact on Leibniz, much more than the telescope. |
| 7560 | Leibniz struggled to reconcile bodies with a reality of purely soul-like entities [Jolley on Leibniz] |
| Full Idea: Leibniz seems never to have made up his mind completely on how to accommodate bodies within a metaphysic which recognises only soul-like entities as fully real. | |
| From: comment on Gottfried Leibniz (works [1690]) by Nicholas Jolley - Leibniz Intro | |
| A reaction: [The soul-like entities are his 'monads']. His choice must be to either say they are unreal, or that they are real and separate from the monads, or that they are a manifestation of the monads. His problem, not mine. |
| 16683 | Leibniz eventually said resistance, rather than extension, was the essence of body [Leibniz, by Pasnau] |
| Full Idea: Leibniz eventually rejected extension altogether as part of the essence of body, and replaced it with resistance. | |
| From: report of Gottfried Leibniz (works [1690]) by Robert Pasnau - Metaphysical Themes 1274-1671 15.5 | |
| A reaction: This makes body consist of active force, rather than mere geometry. Much better. |
| 12725 | Leibniz wanted to explain motion and its laws by the nature of body [Leibniz, by Garber] |
| Full Idea: Leibniz seeks the big picture: the nature of body as a grounding for an account of motion and its laws. | |
| From: report of Gottfried Leibniz (works [1690]) by Daniel Garber - Leibniz:Body,Substance,Monad 4 | |
| A reaction: Garber is contrasting this with Newton's approaches, who just pleads ignorance of the bigger picture. Essentialists must beware of inventing a bigger picture simply because they desperately want a bigger picture. |
| 16507 | The law within something fixes its persistence, and accords with general laws of nature [Leibniz] |
| Full Idea: Nothing is permanent in a substance except the law itself which determines the continuous succession of its states and accords within the individual substance with the laws of nature that govern the whole world. | |
| From: Gottfried Leibniz (works [1690], G II:263), quoted by David Wiggins - Sameness and Substance 3 epig | |
| A reaction: An interesting link between the law-of-series within a substance, and the broader concept of laws outside it. |
| 7859 | Leibniz had an unusual commitment to the causal completeness of physics [Leibniz, by Papineau] |
| Full Idea: Unlike most philosophers prior to the twentieth century, Leibniz was committed to the causal completeness of physics. | |
| From: report of Gottfried Leibniz (works [1690]) by David Papineau - Thinking about Consciousness 1.4 | |
| A reaction: It has been suggested that Leibniz was actually, in private, a determinist (see Idea 7841), which would fit. Leibniz is enigmatic, but he may have proposed the closure of physics to glorify God, only to find that God was beginning to look irrelevant. |
| 24045 | Movement is spatial, alteration, withering or growth [Aristotle] |
| Full Idea: There a four sorts of movement - spatial movement, alteration, withering and growth. | |
| From: Aristotle (De Anima [c.329 BCE], 406a12) | |
| A reaction: Large parts of Aristotle's writings attempt to explain these four. |
| 1738 | Practical reason is based on desire, so desire must be the ultimate producer of movement [Aristotle] |
| Full Idea: There seem to be two producers of movement, either desire or practical intellect, but practical reason begins in desire. | |
| From: Aristotle (De Anima [c.329 BCE], 433a16) |
| 24044 | Movement can be intrinsic (like a ship) or relative (like its sailors) [Aristotle] |
| Full Idea: It is not necessary for what moves things to be itself moving. For a thing can be moving in two ways - with reference to something else, or intrinsically. A ship is moving intrinsically, but sailors move because they are in something that is moving. | |
| From: Aristotle (De Anima [c.329 BCE], 406a03) | |
| A reaction: I love the way that Aristotle is desperate to explain the puzzle of movement, yet we just take it for granted. Very illuminating about puzzles. Newton's First Law of Motion. |
| 1739 | If all movement is either pushing or pulling, there must be a still point in between where it all starts [Aristotle] |
| Full Idea: Every movement being either a push or a pull, there must be a still point as with the circle, and this will be the point of departure for the movement. | |
| From: Aristotle (De Anima [c.329 BCE], 433b26) |
| 24064 | If something is pushed, it pushes back [Aristotle] |
| Full Idea: What has pushed something else makes the latter push as well. | |
| From: Aristotle (De Anima [c.329 BCE], 435b30) | |
| A reaction: Aristotle seems to have spotted that this is intrinsic to massive bodies, and is not just friction etc. Newton adds a vector to Aristotle's insight. |
| 15307 | Leibniz uses 'force' to mean both activity and potential [Leibniz] |
| Full Idea: At this early period exegetical problems abound, since Leibniz uses 'force' both for actually acting forces and for potentials or powers. | |
| From: Gottfried Leibniz (works [1690], 9.II), quoted by Harré,R./Madden,E.H. - Causal Powers 9.II.B | |
| A reaction: I take Leibniz to be a key figure in the development of the Aristotelian approach, because he connected Aristotelian potential and essence with 'force' in the new physics. This is helpful in reading him correctly. |
| 24063 | What is born has growth, a prime, and a withering away [Aristotle] |
| Full Idea: What has been born must have growth, a prime of life, and a time of withering away. | |
| From: Aristotle (De Anima [c.329 BCE], 434a23) | |
| A reaction: Modern biologists don't seem much interested in the 'prime of life', but for Aristotle it is crucial, as the fulfilment of a thing's essential nature. Nietzsche would probably agree with Aristotle on this. We dread seeing one period of life as 'superior'. |
| 3889 | God's existence is either necessary or impossible [Leibniz, by Scruton] |
| Full Idea: Leibniz said that the ontological argument does not prove God's existence, but only the God's existence is either necessary or impossible. | |
| From: report of Gottfried Leibniz (works [1690]) by Roger Scruton - Modern Philosophy:introduction and survey 13.5 |
| 7842 | Leibniz was closer than Spinoza to atheism [Leibniz, by Stewart,M] |
| Full Idea: Leibniz sailed closer to the winds of unbelief than Spinoza did. | |
| From: report of Gottfried Leibniz (works [1690]) by Matthew Stewart - The Courtier and the Heretic Ch.16 | |
| A reaction: This is an unusual view, but Stewart's view is that whereas Spinoza is always sincere in his writings, Leibniz is inclined to put a very conservative spin on his opinions. A key question for Leibniz is "Is God merely a monad?" |