13 ideas
| 18170 | The Axiom of Reducibility is self-effacing: if true, it isn't needed [Quine] |
| Full Idea: The Axiom of Reducibility is self-effacing: if it is true, the ramification it is meant to cope with was pointless to begin with. | |
| From: Willard Quine (Introduction to Russell's Theory of Types [1967], p.152), quoted by Penelope Maddy - Naturalism in Mathematics I.1 | |
| A reaction: Maddy says the rejection of Reducibility collapsed the ramified theory of types into the simple theory. |
| 3626 | Knowing the attributes is enough to reveal a substance [Descartes] |
| Full Idea: I have never thought that anything more is required to reveal a substance than its various attributes. | |
| From: René Descartes (Reply to Fifth Objections [1641], 360) |
| 3630 | Our thinking about external things doesn't disprove the existence of innate ideas [Descartes] |
| Full Idea: You can't prove that Praxiteles never made any statues on the grounds that he did not get from within himself the marble from which he sculpted them. | |
| From: René Descartes (Reply to Fifth Objections [1641], 362) |
| 5163 | Basic propositions refer to a single experience, are incorrigible, and conclusively verifiable [Ayer] |
| Full Idea: There is a class of empirical propositions, which I call 'basic propositions', which can be verified conclusively, since they refer solely to the contents of a single experience, which are incorrigible. | |
| From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.13) | |
| A reaction: A classic statement of empirical foundationalism. I sort of agree that 'single experiences' are a 'given' for philosophy, but is questionable whether there is anything which could both be a single experience AND give rise to a proposition. |
| 5167 | The argument from analogy fails, so the best account of other minds is behaviouristic [Ayer] |
| Full Idea: There are too many objections to the argument from analogy, so I am inclined to revert to a 'behaviouristic' interpretation of propositions about other people's experiences. | |
| From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.26) | |
| A reaction: It seems odd to vote for behaviourism on one issue, if you aren't a general subscriber. It is one thing to say that behaviour is the best evidence for your explanation, quite another to equate the other mind with its behaviour. |
| 3631 | A blind man may still contain the idea of colour [Descartes] |
| Full Idea: How do you know that there is no idea of colour in a man born blind? | |
| From: René Descartes (Reply to Fifth Objections [1641], 363) |
| 5164 | A statement is meaningful if observation statements can be deduced from it [Ayer] |
| Full Idea: In the improved version, a statement was verifiable, and consequently meaningful, if 'some observation-statement can be deduced from it in conjunction with certain other premises, without being deducible from those other premises alone'. | |
| From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.15) | |
| A reaction: I.Berlin showed that any statement S could pass this test, because if you assert 'S' and 'If S then O', these two statements entail O, which could be some random observation. Hence a 1946 revised version had to be produced. |
| 5165 | Directly verifiable statements must entail at least one new observation statement [Ayer] |
| Full Idea: A statement is directly verifiable if it is either itself an observation-statement,or is such that in conjunction with one or more observation-statements it entails at least one observation-statement which is not deducible from these other premises alone. | |
| From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.17) | |
| A reaction: This is the 1946 revised version of the Verification Principle, which was then torpedoed by an elaborate counterexample from Alonzo Church. Ayer thereafter abandoned attempts to find a precise statement of it. |
| 5166 | The principle of verification is not an empirical hypothesis, but a definition [Ayer] |
| Full Idea: I wish the principle of verification to be regarded, not as an empirical hypothesis, but as a definition. | |
| From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.21) | |
| A reaction: This is Ayer's attempt to meet the well known objection of 'turning the tables' on his theory (by asking whether it is tautological or empirically verifiable). However, if it is just a definition, then presumably it is completely arbitrary… |
| 5162 | Sentences only express propositions if they are meaningful; otherwise they are 'statements' [Ayer] |
| Full Idea: I suggest that every grammatically significant indicative sentence expresses a 'statement', but the word 'proposition' will be reserved for what is expressed by sentences that are literally meaningful. | |
| From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.10) | |
| A reaction: We don't have to accept Ayer's over-fussy requirements for what is meaningful to accept that this is a good distinction. Every day we hear statements from people (e.g. politicians) in which we can fish in vain for the underlying proposition. |
| 5168 | Moral approval and disapproval concerns classes of actions, rather than particular actions [Ayer] |
| Full Idea: The common objects of moral approval and disapproval are not particular actions so much as classes of actions. | |
| From: A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.27) | |
| A reaction: This 1946 revision of his pure emotivism looks like a move towards Hare's prescriptivism, where classes, rules and principles are seen as the window-dressing of emotivism. It's still a bad theory. |
| 3640 | Possible existence is a perfection in the idea of a triangle [Descartes] |
| Full Idea: Possible existence is a perfection in the idea of a triangle, just as necessary existence is a perfection in the idea of God. | |
| From: René Descartes (Reply to Fifth Objections [1641], 383) |
| 3639 | Necessary existence is a property which is uniquely part of God's essence [Descartes] |
| Full Idea: In the case of God necessary existence is in fact a property in the strictest sense of the term, since it applies to him alone and forms a part of his essence as it does of no other thing | |
| From: René Descartes (Reply to Fifth Objections [1641], 383) |