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2 ideas
| 9023 | If you say that a contradiction is true, you change the meaning of 'not', and so change the subject [Quine] |
| Full Idea: Those who regard the conjunction p.not-p as true think they are talking about negation, 'not', but this ceases to be recognisable as negation. The deviant logician's predicament is when he tries to deny the doctrine he only changes the subject. | |
| From: Willard Quine (Philosophy of Logic [1970], Ch.6) | |
| A reaction: The charge of 'changing the subject' has become a classic move in modern discussions of non-standard logics. It is an important idea in discussions of arguments, and is found in Kant's account of the Ontological Argument. |
| 15957 | Essential definitions show the differences that discriminate things, and make them what they are [Boyle] |
| Full Idea: Essential definitions are such as are taken from the essential differences of things, which constitute them in such a sort of natural bodies, and discriminate them from all those of any other sort. | |
| From: Robert Boyle (The Origin of Forms and Qualities [1666], p.41?), quoted by Peter Alexander - Ideas, Qualities and Corpuscles | |
| A reaction: I don't think this goes as far as the aim Aristotle had in definitions, which was more than merely to 'discriminate' each thing. A full definition explains the thing as well. |