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Single Idea 16896

[filed under theme 6. Mathematics / B. Foundations for Mathematics / 6. Mathematics as Set Theory / b. Mathematics is not set theory ]

Full Idea

Frege thought that if one could derive the existence of numbers from logical concepts, one would not need set theory to explain number theory, or for any other good purpose.

Gist of Idea

If numbers can be derived from logic, then set theory is superfluous

Source

report of Gottlob Frege (Grundlagen der Arithmetik (Foundations) [1884]) by Tyler Burge - Frege on Apriority (with ps) 2

Book Ref

Burge,Tyler: 'Truth, Thought, Reason (on Frege)' [OUP 2001], p.371


A Reaction

Note that we have two possible routes to 'explain' numbers. I'm inclined to see set theory as modelling numbers rather than explaining them. Frege did better at explanation, but I suspect he is wrong too.


The 14 ideas with the same theme [denial that mathematics is just set theory]:

If numbers can be derived from logic, then set theory is superfluous [Frege, by Burge]
The theory of classes is superfluous in mathematics [Wittgenstein]
Disputes about mathematical objects seem irrelevant, and mathematicians cannot resolve them [Benacerraf, by Friend]
No particular pair of sets can tell us what 'two' is, just by one-to-one correlation [Benacerraf, by Lowe]
If ordinal numbers are 'reducible to' some set-theory, then which is which? [Benacerraf]
You can ask all sorts of numerical questions about any one given set [Yourgrau]
We can't use sets as foundations for mathematics if we must await results from the upper reaches [Yourgrau]
Set-theoretic imperialists think sets can represent every mathematical object [Fine,K]
Mathematical foundations may not be sets; categories are a popular rival [Shapiro]
Sets exist where their elements are, but numbers are more like universals [Maddy]
Number theory doesn't 'reduce' to set theory, because sets have number properties [Maddy]
Set theory may represent all of mathematics, without actually being mathematics [Brown,JR]
When graphs are defined set-theoretically, that won't cover unlabelled graphs [Brown,JR]
Numbers are properties, not sets (because numbers are magnitudes) [Hossack]