Combining Philosophers

All the ideas for William S. Jevons, Anon (Plat) and Sphaerus

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3 ideas

6. Mathematics / C. Sources of Mathematics / 6. Logicism / a. Early logicism
I hold that algebra and number are developments of logic [Jevons]
     Full Idea: I hold that algebra is a highly developed logic, and number but logical discrimination.
     From: William S. Jevons (The Principles of Science [1879], p.156), quoted by Gottlob Frege - Grundlagen der Arithmetik (Foundations) §15
     A reaction: Thus Frege shows that logicism was an idea that was in the air before he started writing. Riemann's geometry and Boole's logic presumably had some influence here.
13. Knowledge Criteria / A. Justification Problems / 2. Justification Challenges / c. Knowledge closure
Sphaerus he was not assenting to the presence of pomegranates, but that it was 'reasonable' [Sphaerus, by Diog. Laertius]
     Full Idea: When Sphaerus accepted pomegranates from the king, he was accused of assenting to a false presentation, to which Sphaerus replied that what he had assented to was not that they were pomegranates, but that it was reasonable that they were pomegranates.
     From: report of Sphaerus (fragments/reports [c.240 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 07.177
     A reaction: He then cited the stoic distinction between a 'graspable' presentation and a 'reasonable' one. This seems a rather helpful response to Dretske's zebra problem. I like the word 'sensible' in epistemology, because animals can be sensible.
17. Mind and Body / A. Mind-Body Dualism / 1. Dualism
Man uses his body, so must be separate from it [Anon (Plat), by Maslin]
     Full Idea: A man uses his whole body to do things, and therefore, just as a person is distinct from a tool he uses, so it follows that a man must be distinct from his body.
     From: report of Anon (Plat) (Alcibiades [c.340 BCE]) by Keith T. Maslin - Introduction to the Philosophy of Mind 2.3
     A reaction: This 'follows'? Every part of my body and my mind makes 'use' of every other part. My body uses my mind to achieve reproduction. He presumably means 'person' rather than 'man'.