3 ideas
| 18151 | Could we replace sets by the open sentences that define them? [Chihara, by Bostock] |
| Full Idea: Chihara proposes to replace all sets by reference to the open sentences that define them. | |
| From: report of Charles Chihara (Ontology and the Vicious Circle Principle [1973]) by David Bostock - Philosophy of Mathematics 9.B.4 | |
| A reaction: This depends on predicativism, because that stipulates the definitions will be available (cos if it ain't definable it ain't there). Chihara went on to define the open sentences in terms of the possibility of uttering them. Cf. propositional functions. |
| 10245 | One geometry cannot be more true than another [Poincaré] |
| Full Idea: One geometry cannot be more true than another; it can only be more convenient. | |
| From: Henri Poincaré (Science and Method [1908], p.65), quoted by Stewart Shapiro - Philosophy of Mathematics | |
| A reaction: This is the culminating view after new geometries were developed by tinkering with Euclid's parallels postulate. |
| 15540 | You can't deny temporary intrinsic properties by saying the properties are relations (to times) [Lewis] |
| Full Idea: To say that properties are really relations to times is to treat temporary intrinsics (such as my changing shape) as a matter of relations, but then 'intrinsic properties' would not deserve the name, and it is untenable if it denies temporary intrinsics. | |
| From: David Lewis (Rearrangement of Particles [1988], 1) | |
| A reaction: [I have compressed a paragraph; he refers to his 1986:204] If a property is meant to be a 'relation to a time', I am not sure what the relata are meant to be, and I agree with Lewis that this seems a long way from properties. |