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Single Idea 8758

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

Full Idea

Chihara's programme is to replace talk of sets with talk of open sentences. Instead of speaking of the set of all cats, we talk about the open sentence 'x is a cat'.

Clarification

An open sentence has a free variable in it

Gist of Idea

We could talk of open sentences, instead of sets

Source

report of Charles Chihara (Constructibility and Mathematical Existence [1990]) by Stewart Shapiro - Thinking About Mathematics 9.2

Book Ref

Shapiro,Stewart: 'Thinking About Mathematics' [OUP 2000], p.239


A Reaction

As Shapiro points out, this is following up Russell's view that sets should be replaced with talk of properties. Chihara is expressing it more linguistically. I'm in favour of any attempt to get rid of sets.


The 22 ideas from Charles Chihara

We could talk of open sentences, instead of sets [Chihara, by Shapiro]
Chihara's system is a variant of type theory, from which he can translate sentences [Chihara, by Shapiro]
We can replace type theory with open sentences and a constructibility quantifier [Chihara, by Shapiro]
Introduce a constructibility quantifiers (Cx)Φ - 'it is possible to construct an x such that Φ' [Chihara, by Shapiro]
Could we replace sets by the open sentences that define them? [Chihara, by Bostock]
We can replace existence of sets with possibility of constructing token sentences [Chihara, by MacBride]
Mathematical entities are causally inert, so the causal theory of reference won't work for them [Chihara]
The set theorist cannot tell us what 'membership' is [Chihara]
We only know relational facts about the empty set, but nothing intrinsic [Chihara]
What is special about Bill Clinton's unit set, in comparison with all the others? [Chihara]
Sentences are consistent if they can all be true; for Frege it is that no contradiction can be deduced [Chihara]
Analytic geometry gave space a mathematical structure, which could then have axioms [Chihara]
If a successful theory confirms mathematics, presumably a failed theory disconfirms it? [Chihara]
The mathematics of relations is entirely covered by ordered pairs [Chihara]
In simple type theory there is a hierarchy of null sets [Chihara]
A pack of wolves doesn't cease when one member dies [Chihara]
No scientific explanation would collapse if mathematical objects were shown not to exist [Chihara]
I prefer the open sentences of a Constructibility Theory, to Platonist ideas of 'equivalence classes' [Chihara]
ZFU refers to the physical world, when it talks of 'urelements' [Chihara]
The null set is a structural position which has no other position in membership relation [Chihara]
Realists about sets say there exists a null set in the real world, with no members [Chihara]
'Gunk' is an individual possessing no parts that are atoms [Chihara]