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Single Idea 24137

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

Full Idea

Mathematics contains axioms (definitions) and conclusions from definitions. Its objects do not exist. The truth of its conclusions rests on the accuracy of logical thought.

Gist of Idea

Mathematics is just accurate inferences from definitions, and doesn't involve objects

Source

Friedrich Nietzsche (Unpublished Notebooks 1884-85 [1884], 25[307])

Book Ref

Nietzsche,Friedrich: 'Fragments from 1884-85 (v 15)', ed/tr. Loeb,P.S./Tinsley,D.F. [Stanford 2022], p.78


A Reaction

Not suprising to find Nietzsche defying platonism. This is evidence that he was a systematic philosopher, who knew mathematics could be a challenge to his naturalism.


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]