15943 | Limitation of Size is not self-evident, and seems too strong [Lavine on Neumann] |
Full Idea: Von Neumann's Limitation of Size axiom is not self-evident, and he himself admitted that it seemed too strong. | |
From: comment on John von Neumann (An Axiomatization of Set Theory [1925]) by Shaughan Lavine - Understanding the Infinite VII.1 |
13547 | Limitation of Size is weak (Fs only collect is something the same size does) or strong (fewer Fs than objects) [Boolos, by Potter] |
Full Idea: Weak Limitation of Size: If there are no more Fs than Gs and the Gs form a collection, then Fs form a collection. Strong Limitation of Size: A property F fails to be collectivising iff there are as many Fs as there are objects. | |
From: report of George Boolos (Iteration Again [1989]) by Michael Potter - Set Theory and Its Philosophy 13.5 |
18105 | Replacement enforces a 'limitation of size' test for the existence of sets [Bostock] |
Full Idea: The Axiom of Replacement (or the Axiom of Subsets, 'Aussonderung', Fraenkel 1922) in effect enforces the idea that 'limitation of size' is a crucial factor when deciding whether a proposed set or does not not exist. | |
From: David Bostock (Philosophy of Mathematics [2009], 5.4) |
17803 | Limitation of size is part of the very conception of a set [Mayberry] |
Full Idea: Our very notion of a set is that of an extensional plurality limited in size. | |
From: John Mayberry (What Required for Foundation for Maths? [1994], p.415-2) |
13018 | Limitation of Size is a vague intuition that over-large sets may generate paradoxes [Maddy] |
Full Idea: The 'limitation of size' is a vague intuition, based on the idea that being too large may generate the paradoxes. | |
From: Penelope Maddy (Believing the Axioms I [1988], §1.3) | |
A reaction: This is an intriguing idea to be found right at the centre of what is supposed to be an incredibly rigorous system. |
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. |
15933 | Limitation of Size: if it's the same size as a set, it's a set; it uses Replacement [Lavine] |
Full Idea: Limitation of Size has it that if a collection is the same size as a set, then it is a set. The Axiom of Replacement is characteristic of limitation of size. | |
From: Shaughan Lavine (Understanding the Infinite [1994], V.5) |
23625 | Limitation of Size justifies Replacement, but then has to appropriate Power Set [Hossack] |
Full Idea: The limitation of size conception of sets justifies the axiom of Replacement, but cannot justify Power Set, so NBG set theory appropriates the Power Set axiom from ZFC. | |
From: Keith Hossack (Knowledge and the Philosophy of Number [2020], 09.9) | |
A reaction: Which suggests that the Power Set axiom is not as indispensable as it at first appears to be. |