5 ideas
21563 | The 'no classes' theory says the propositions just refer to the members [Russell] |
Full Idea: The contention of the 'no classes' theory is that all significant propositions concerning classes can be regarded as propositions about all or some of their members. | |
From: Bertrand Russell (On 'Insolubilia' and their solution [1906], p.200) | |
A reaction: Apparently this theory has not found favour with later generations of theorists. I see it in terms of Russell trying to get ontology down to the minimum, in the spirit of Goodman and Quine. |
21565 | Richard's puzzle uses the notion of 'definition' - but that cannot be defined [Russell] |
Full Idea: In Richard's puzzle, we use the notion of 'definition', and this, oddly enough, is not definable, and is indeed not a definite notion at all. | |
From: Bertrand Russell (On 'Insolubilia' and their solution [1906], p.209) | |
A reaction: The background for this claim is his type theory, which renders certain forms of circular reference meaningless. |
21564 | Vicious Circle: what involves ALL must not be one of those ALL [Russell] |
Full Idea: The 'vicious-circle principle' says 'whatever involves an apparent variable must not be among the possible values of that variable', or (less exactly) 'whatever involves ALL must not be one of ALL which it involves. | |
From: Bertrand Russell (On 'Insolubilia' and their solution [1906], p.204) | |
A reaction: He offers this as a parallel to his 'no classes' principle. That referred to classes, but this refers to propositions, and specifically the Liar Paradox (which he calls the 'Epimenedes'). |
13007 | Archimedes defined a straight line as the shortest distance between two points [Archimedes, by Leibniz] |
Full Idea: Archimedes gave a sort of definition of 'straight line' when he said it is the shortest line between two points. | |
From: report of Archimedes (fragments/reports [c.240 BCE]) by Gottfried Leibniz - New Essays on Human Understanding 4.13 | |
A reaction: Commentators observe that this reduces the purity of the original Euclidean axioms, because it involves distance and measurement, which are absent from the purest geometry. |
7296 | 'Grue' is not a colour [Milsted] |
Full Idea: 'Grue' is not a colour. | |
From: Tom Milsted (talk [2006]), quoted by PG - Db (ideas) | |
A reaction: This simple observation strikes me as rather crucial in assessing Goodman's paradox. Blue is a colour, but grue is some sort of behaviour. Blue is a secondary quality, but grue seems to be a primary quality. |