display all the ideas for this combination of texts
6 ideas
10702 | Set theory's three roles: taming the infinite, subject-matter of mathematics, and modes of reasoning [Potter] |
Full Idea: Set theory has three roles: as a means of taming the infinite, as a supplier of the subject-matter of mathematics, and as a source of its modes of reasoning. | |
From: Michael Potter (Set Theory and Its Philosophy [2004], Intro 1) | |
A reaction: These all seem to be connected with mathematics, but there is also ontological interest in set theory. Potter emphasises that his second role does not entail a commitment to sets 'being' numbers. |
10713 | Usually the only reason given for accepting the empty set is convenience [Potter] |
Full Idea: It is rare to find any direct reason given for believing that the empty set exists, except for variants of Dedekind's argument from convenience. | |
From: Michael Potter (Set Theory and Its Philosophy [2004], 04.3) |
13044 | Infinity: There is at least one limit level [Potter] |
Full Idea: Axiom of Infinity: There is at least one limit level. | |
From: Michael Potter (Set Theory and Its Philosophy [2004], 04.9) | |
A reaction: A 'limit ordinal' is one which has successors, but no predecessors. The axiom just says there is at least one infinity. |
10708 | Nowadays we derive our conception of collections from the dependence between them [Potter] |
Full Idea: It is only quite recently that the idea has emerged of deriving our conception of collections from a relation of dependence between them. | |
From: Michael Potter (Set Theory and Its Philosophy [2004], 03.2) | |
A reaction: This is the 'iterative' view of sets, which he traces back to Gödel's 'What is Cantor's Continuum Problem?' |
13546 | The 'limitation of size' principles say whether properties collectivise depends on the number of objects [Potter] |
Full Idea: We group under the heading 'limitation of size' those principles which classify properties as collectivizing or not according to how many objects there are with the property. | |
From: Michael Potter (Set Theory and Its Philosophy [2004], 13.5) | |
A reaction: The idea was floated by Cantor, toyed with by Russell (1906), and advocated by von Neumann. The thought is simply that paradoxes start to appear when sets become enormous. |
10707 | Mereology elides the distinction between the cards in a pack and the suits [Potter] |
Full Idea: Mereology tends to elide the distinction between the cards in a pack and the suits. | |
From: Michael Potter (Set Theory and Its Philosophy [2004], 02.1) | |
A reaction: The example is a favourite of Frege's. Potter is giving a reason why mathematicians opted for set theory. I'm not clear, though, why a pack cannot have either 4 parts or 52 parts. Parts can 'fall under a concept' (such as 'legs'). I'm puzzled. |