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Single Idea 13506

[filed under theme 5. Theory of Logic / G. Quantification / 3. Objectual Quantification ]

Full Idea

All the main set theories deny that there is a set of which everything is a member. No interpretation has a domain with everything in it. So the universal quantifier never gets to mean everything all at once; 'all' does not mean all.

Gist of Idea

The universal quantifier can't really mean 'all', because there is no universal set

Source

William D. Hart (The Evolution of Logic [2010], 4)

Book Ref

Hart,W.D.: 'The Evolution of Logic' [CUP 2010], p.111


A Reaction

Could you have an 'uncompleted' universal set, in the spirit of uncompleted infinities? In ordinary English we can talk about 'absolutely everything' - we just can't define a set of everything. Must we 'define' our domain?


The 9 ideas with the same theme [universal and existential quantifiers picking objects]:

Aristotelian logic has two quantifiers of the subject ('all' and 'some') [Aristotle, by Devlin]
Frege reduced most quantifiers to 'everything' combined with 'not' [Frege, by McCullogh]
Frege introduced quantifiers for generality [Frege, by Weiner]
Existence is entirely expressed by the existential quantifier [Russell, by McGinn]
'Partial quantifier' would be a better name than 'existential quantifier', as no existence would be implied [McGinn]
'All horses' either picks out the horses, or the things which are horses [Jubien]
Philosophers reduce complex English kind-quantifiers to the simplistic first-order quantifier [Jubien]
The universal quantifier can't really mean 'all', because there is no universal set [Hart,WD]
It is better if the existential quantifier refers to 'something', rather than a 'thing' which needs individuation [Lowe]