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Single Idea 10055

[filed under theme 5. Theory of Logic / C. Ontology of Logic / 3. If-Thenism ]

Full Idea

All the demonstrations of mathematicians are the same, whether there be any square or circle existing in the world or no.

Gist of Idea

Mathematical proofs work, irrespective of whether the objects exist

Source

John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 4.04.08)

Book Ref

Locke,John: 'Essay Concerning Human Understanding', ed/tr. Nidditch,P.H. [OUP 1979], p.566


A Reaction

Musgrave gives this as an early indication of the if-thenist view of mathematics.


The 13 ideas with the same theme [logic is only inference without commitment to initial truths]:

Arithmetic and geometry achieve some certainty without worrying about existence [Descartes]
Mathematical proofs work, irrespective of whether the objects exist [Locke]
At bottom eternal truths are all conditional [Leibniz]
Logic, unlike mathematics, is not hypothetical; it asserts categorical ends from hypothetical means [Peirce]
Pure mathematics deals only with hypotheses, of which the reality does not matter [Peirce]
Mathematics is just accurate inferences from definitions, and doesn't involve objects [Nietzsche]
Geometrical axioms imply the propositions, but the former may not be true [Russell]
Quine quickly dismisses If-thenism [Quine, by Musgrave]
Putnam coined the term 'if-thenism' [Putnam, by Musgrave]
The If-thenist view only seems to work for the axiomatised portions of mathematics [Musgrave]
Perhaps If-thenism survives in mathematics if we stick to first-order logic [Musgrave]
Critics of if-thenism say that not all starting points, even consistent ones, are worth studying [Maddy]
Deductivism can't explain how the world supports unconditional conclusions [Potter]