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Single Idea 8784

[filed under theme 6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / d. Hume's Principle ]

Full Idea

The result of joining Hume's Principle to second-order logic is a consistent system which is a foundation for arithmetic, in the sense that all the fundamental laws of arithmetic are derivable within it as theorems. This seems a vindication of logicism.

Clarification

Hume's Principle involves one-to-one correlation

Gist of Idea

Neo-logicism founds arithmetic on Hume's Principle along with second-order logic

Source

B Hale / C Wright (Logicism in the 21st Century [2007], 1)

Book Ref

'Oxf Handbk of Philosophy of Maths and Logic', ed/tr. Shapiro,Stewart [OUP 2007], p.169


A Reaction

The controversial part seems to be second-order logic, which Quine (for example) vigorously challenged. The contention against most attempts to improve Frege's logicism is that they thereby cease to be properly logical.


The 19 ideas with the same theme [view that one-one correspondence is basis of numbers]:

Two numbers are equal if all of their units correspond to one another [Hume]
'The number of Fs' is the extension (a collection of first-level concepts) of the concept 'equinumerous with F' [Frege, by George/Velleman]
Frege's cardinals (equivalences of one-one correspondences) is not permissible in ZFC [Frege, by Wolf,RS]
Hume's Principle fails to implicitly define numbers, because of the Julius Caesar [Frege, by Potter]
Frege thinks number is fundamentally bound up with one-one correspondence [Frege, by Heck]
A number is something which characterises collections of the same size [Russell]
Many things will satisfy Hume's Principle, so there are many interpretations of it [Bostock]
Hume's Principle is a definition with existential claims, and won't explain numbers [Bostock]
There are many criteria for the identity of numbers [Bostock]
We derive Hume's Law from Law V, then discard the latter in deriving arithmetic [Wright,C, by Fine,K]
Frege has a good system if his 'number principle' replaces his basic law V [Wright,C, by Friend]
Wright says Hume's Principle is analytic of cardinal numbers, like a definition [Wright,C, by Heck]
It is 1-1 correlation of concepts, and not progression, which distinguishes natural number [Wright,C]
Neo-logicism founds arithmetic on Hume's Principle along with second-order logic [Hale/Wright]
If Hume's Principle can define numbers, we needn't worry about its truth [Fine,K]
Hume's Principle is either adequate for number but fails to define properly, or vice versa [Fine,K]
Simple counting is more basic than spotting that one-to-one correlation makes sets equinumerous [Lowe]
Fs and Gs are identical in number if they one-to-one correlate with one another [Lowe]
Frege's Theorem shows the Peano Postulates can be derived from Hume's Principle [George/Velleman]