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Single Idea 8972

[filed under theme 4. Formal Logic / F. Set Theory ST / 8. Critique of Set Theory ]

Full Idea

Nothing in the world of nominalistically acceptable things could ground or explain the non-identity of the set {A,{A,B}} with the set {B,{A,B}}.

Gist of Idea

What in the real world could ground the distinction between the sets {A,{A,B}} and {B,{A,B}}?

Source

Peter van Inwagen (Existence,Ontological Commitment and Fictions [2003], p.154)

Book Ref

'The Oxford Handbook of Metaphysics', ed/tr. Loux,M /Zimmerman,D [OUP 2005], p.154


A Reaction

[He cites Goodman for this thought] Van Inwagen is offering this to show that the existence of sets is abstract, whereas Goodman was denying the existence of sets altogether. I'm with Goodman. Nice example.


The 23 ideas with the same theme [objections to the whole idea of set theory]:

Classes are logical fictions, and are not part of the ultimate furniture of the world [Russell]
I gradually replaced classes with properties, and they ended as a symbolic convenience [Russell]
Russell denies extensional sets, because the null can't be a collection, and the singleton is just its element [Russell/Whitehead, by Shapiro]
We regard classes as mere symbolic or linguistic conveniences [Russell/Whitehead]
Classes can be reduced to propositional functions [Russell, by Hanna]
Classes, grouped by a convenient property, are logical constructions [Russell]
Skolem did not believe in the existence of uncountable sets [Skolem]
Very few things in set theory remain valid in intuitionist mathematics [Bernays]
Von Neumann wanted mathematical functions to replace sets [Neumann, by Benardete,JA]
Two objects can apparently make up quite distinct arrangements in sets [Goodman, by Burgess/Rosen]
Two things can never entail three things [Quine, by Benardete,JA]
Does a bowl of Cheerios contain all its sets and subsets? [Boolos]
What in the real world could ground the distinction between the sets {A,{A,B}} and {B,{A,B}}? [Inwagen]
In Field's Platonist view, set theory is false because it asserts existence for non-existent things [Field,H, by Chihara]
Physicalism requires the naturalisation or rejection of set theory [Lycan]
Maybe sets should be rethought in terms of the even more basic categories [Hart,WD]
God does not create the world, and then add the classes [Heil]
Anti-realists reject set theory [Shapiro]
We could talk of open sentences, instead of sets [Chihara, by Shapiro]
Could we replace sets by the open sentences that define them? [Chihara, by Bostock]
A pack of wolves doesn't cease when one member dies [Chihara]
As a reduction of arithmetic, set theory is not fully general, and so not logical [George/Velleman]
Maybe we reduce sets to ordinals, rather than the other way round [Hossack]