21 ideas
| 1922 | Spiritual qualities only become advantageous with the growth of wisdom [Plato] |
| Full Idea: If virtue is a beneficial attribute of spirit, it must be wisdom; for spiritual qualities are not in themselves advantageous, but become so with wisdom…..Hence men cannot be good by nature. | |
| From: Plato (Meno [c.385 BCE], 88c) | |
| A reaction: Personally I haven't got any 'spiritual qualities', so I don't really understand this. |
| 9456 | Modal logic is multiple systems, shown in the variety of accessibility relations between worlds [Jacquette] |
| Full Idea: Modal logic by its very nature is not monolithic, but fragmented into multiple systems of modal qualifications, reflected in the plurality of accessibility relations on modal model structures or logically possible worlds. | |
| From: Dale Jacquette (Intro to 'Philosophy of Logic' [2002], §3) | |
| A reaction: He implies the multiplicity is basic, and is only 'reflected' in the relations, but maybe the multiplicity is caused by incompetent logicians who can't decide whether possible worlds really are reflexive or symmetrical or transitive in their relations. |
| 9457 | The two main views in philosophy of logic are extensionalism and intensionalism [Jacquette] |
| Full Idea: Philosophy of logic has (roughly) two camps: extensionalists and intensionalists, with the former view dominant. ...There is a close connection between this and eliminativist or reductivist versus folk psychological and intentionalist philosophy of mind. | |
| From: Dale Jacquette (Intro to 'Philosophy of Logic' [2002], §4) | |
| A reaction: Hm. I think I favour intensionalism in the logic, and reductivism about the mind, so I may have a bit of bother here. I'm convinced that this jigsaw can be completed, despite all appearances. |
| 9458 | Extensionalists say that quantifiers presuppose the existence of their objects [Jacquette] |
| Full Idea: Extensionalists hold that quantifiers in predicate logic presuppose the existence of whatever objects can be referred to by constants or bound variables, or enter into true predication of properties. | |
| From: Dale Jacquette (Intro to 'Philosophy of Logic' [2002], §4) | |
| A reaction: I have strong sales resistance to this view. Why should a procedure for correctly reasoning from one proposition to another have anything whatever to do with ontology? A false world picture can be interconnected by perfect logic. |
| 9461 | Intensionalists say meaning is determined by the possession of properties [Jacquette] |
| Full Idea: According to intensionalist semantics the meaning of a proposition is determined by the properties an object possesses. | |
| From: Dale Jacquette (Intro to 'Philosophy of Logic' [2002], §4) | |
| A reaction: This sounds good to me. Extensionalist don't seem to care what sets they put things in, but if property possession comes first, then things will fall into their own sets without any help for us. We can add silly sets afterwards, if we fancy. |
| 11259 | How can you seek knowledge of something if you don't know it? [Plato] |
| Full Idea: How will you aim to search for something you do not know at all? If you should meet with it, how will you know that this is the thing that you did not know? | |
| From: Plato (Meno [c.385 BCE], 80d05) | |
| A reaction: Vasilis Politis cites this as a nice example of the 'aporiai' (puzzles) which Aristotle said were the foundation of enquiry. Nowadays the problem is called the 'paradox of enquiry'. |
| 20219 | True opinions only become really valuable when they are tied down by reasons [Plato] |
| Full Idea: True opinions are a fine thing and all they do is good, …but they escape from a man's mind, so they are not worth much until one ties them down by (giving) an account of the reason why. | |
| From: Plato (Meno [c.385 BCE], 98a3) | |
| A reaction: This gives justification the role of guarantee, stabilising and securing true beliefs (rather than triggering some new thing called 'knowledge'). |
| 5985 | Seeking and learning are just recollection [Plato] |
| Full Idea: Seeking and learning are in fact nothing but recollection. | |
| From: Plato (Meno [c.385 BCE], 81d) | |
| A reaction: This is a prelude to the famous conversation with the slave boy about geometry. You don't have to follow Plato into the doctrine of reincarnation; this remark is a key slogan for all rationalists. As pupils in maths lessons, we pull knowledge from within. |
| 5986 | The slave boy learns geometry from questioning, not teaching, so it is recollection [Plato] |
| Full Idea: The slave boy's knowledge of geometry will not come from teaching but from questioning; he will recover it for himself, and the spontaneous recovery of knowledge that is in him is recollection. | |
| From: Plato (Meno [c.385 BCE], 85d) | |
| A reaction: Of course, if maths and geometry are huge tautological axiom systems, we would expect to be able to derive them (with hints from a teacher) entirely from their axioms. It is not clear why we might be able to derive the truths of all nature a priori. |
| 1923 | As a guide to action, true opinion is as good as knowledge [Plato] |
| Full Idea: True opinion is as good a guide as knowledge for the purpose of acting rightly. | |
| From: Plato (Meno [c.385 BCE], 97b) | |
| A reaction: This is the germ of Peirce's epistemology - that knowledge is an interesting theoretical concept, but opinion/belief is what matters, and most needs explanation. |
| 1919 | You don't need to learn what you know, and how do you seek for what you don't know? [Plato] |
| Full Idea: You could argue that a man cannot discover what he does know or what he doesn't. The first needs no discovery, and how do you begin looking for the second? | |
| From: Plato (Meno [c.385 BCE], 80e) |
| 7444 | Type-type psychophysical identity is combined with a functional characterisation of pain [Lewis] |
| Full Idea: The materialist theory Armstrong and I proposed joins claims of type-type psychophysical identity with a behaviourist or functionalist way of characterising mental states such as pain. | |
| From: David Lewis (Mad Pain and Martian Pain [1980], §III) | |
| A reaction: Armstrong has backed off from 'type-type' identity, because the realisations of a given mental state might be too diverse to be considered of the same type. Putnam's machine functionalism allows the possibility of dualism. |
| 7445 | The application of 'pain' to physical states is non-rigid and contingent [Lewis] |
| Full Idea: The word 'pain' is a non-rigid designator; it is a contingent matter what state the concept and the word apply to. (Note: so the sort of theory Kripke argues against is not what we propose). | |
| From: David Lewis (Mad Pain and Martian Pain [1980], §III) | |
| A reaction: I like the view that a given quale is necessarily identical to a given mental state, but that many mental states might occupy a given behavioural role. The smell of roses might occupy the behavioural role of pain. Frog pain isn't quite like ours. |
| 7443 | A theory must be mixed, to cover qualia without behaviour, and behaviour without qualia [Lewis, by PG] |
| Full Idea: To pass our test it seems that our theory will have to be a 'mixed' theory, to account for the Madman (whose pain has odd causes, and odd effects) and also for the Martian (who has normal causes and effects, but an odd physical state). | |
| From: report of David Lewis (Mad Pain and Martian Pain [1980], §II) by PG - Db (ideas) | |
| A reaction: A statement that 'pain' is ambiguous (qualia/causal role) would help a lot here. Martians have the causal role but no qualia, and the madman has the qualia but lacks the causal role. I say lots of different qualia might have the same causal role. |
| 9460 | Extensionalist semantics forbids reference to nonexistent objects [Jacquette] |
| Full Idea: In extensionalist semantics only existent objects can be referred to, ...but in everyday thought and discourse we regularly and apparently without undue confusion speak about nonexistent objects. | |
| From: Dale Jacquette (Intro to 'Philosophy of Logic' [2002], §4) | |
| A reaction: This is the reason why Meinong, whose views are presented by Russell as absurd, are undergoing a revival. The full-blown view will even treat 'round squares' as objects about which we can reason - and why not? Don't open a shop which sells them. |
| 9459 | Extensionalist semantics is circular, as we must know the extension before assessing 'Fa' [Jacquette] |
| Full Idea: Extensional semantics is blatantly circular. For 'Fa' to be interpreted as true, we must know that object a belongs to the extension of the predicate F, so we must already know which objects belong to the extension. | |
| From: Dale Jacquette (Intro to 'Philosophy of Logic' [2002], §4) | |
| A reaction: I'm delighted to read this, because it was the first thought that occurred to me when I encountered the theory. Presumably this leads Quine to take predication as basic, because you can't break into the circle. Or, vote for intensionalism? |
| 1913 | Is virtue taught, or achieved by practice, or a natural aptitude, or what? [Plato] |
| Full Idea: Is virtue something that can be taught, or does it come by practice, or is it a natural aptitude, or something else? | |
| From: Plato (Meno [c.385 BCE], 70a) |
| 1921 | If virtue is a type of knowledge then it ought to be taught [Plato] |
| Full Idea: If virtue is some sort of knowledge, then clearly it could be taught. | |
| From: Plato (Meno [c.385 BCE], 87c) |
| 1927 | It seems that virtue is neither natural nor taught, but is a divine gift [Plato] |
| Full Idea: If our discussion is right, virtue is acquired neither by nature nor by teaching. Whoever has it gets it by divine dispensation, without taking thought. | |
| From: Plato (Meno [c.385 BCE], 99e) |
| 1918 | How can you know part of virtue without knowing the whole? [Plato] |
| Full Idea: Does anyone know what a part of virtue is without knowing the whole? | |
| From: Plato (Meno [c.385 BCE], 79c) |
| 1916 | Even if virtues are many and various, they must have something in common to make them virtues [Plato] |
| Full Idea: Even if virtues are many and various, at least they all have some common character which makes them all virtues. | |
| From: Plato (Meno [c.385 BCE], 72c) |