4 ideas
9565 | Zermelo made 'set' and 'member' undefined axioms [Zermelo, by Chihara] |
Full Idea: The terms 'set' and 'is a member of' are primitives of Zermelo's 1908 axiomatization of set theory. They are not given model-theoretic analyses or definitions. | |
From: report of Ernst Zermelo (works [1920]) by Charles Chihara - A Structural Account of Mathematics 7.5 | |
A reaction: This looks like good practice if you want to work with sets, but not so hot if you are interested in metaphysics. |
3339 | For Zermelo's set theory the empty set is zero and the successor of each number is its unit set [Zermelo, by Blackburn] |
Full Idea: For Zermelo's set theory the empty set is zero and the successor of each number is its unit set. | |
From: report of Ernst Zermelo (works [1920]) by Simon Blackburn - Oxford Dictionary of Philosophy p.280 |
16705 | Whiteness isn't created in an alteration, because it is just this-being-white [Oresme] |
Full Idea: If it is said that whiteness begins to be through alteration, this does not hold, because whiteness is nothing other than this-being-white. | |
From: Nicole Oresme (On 'Generation and Corruption' [1349], I.2), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 19.3 | |
A reaction: This innocent-looking remark is dynamite, because it rejects the separability of qualities, which threatens the doctrine of Transubstantiation. |
23873 | Dividing history books into separate chapters is disastrous [Weil] |
Full Idea: The division of history textbooks into chapters will cost us many disastrous mistakes. | |
From: Simone Weil (Fragments [1936], p.131) | |
A reaction: Nice observation. The point is that we fail to grasp what really happened if we draw sharp lines across history. |