3 ideas
13416 | Mathematics must be based on axioms, which are true because they are axioms, not vice versa [Tait, by Parsons,C] |
Full Idea: The axiomatic conception of mathematics is the only viable one. ...But they are true because they are axioms, in contrast to the view advanced by Frege (to Hilbert) that to be a candidate for axiomhood a statement must be true. | |
From: report of William W. Tait (Intro to 'Provenance of Pure Reason' [2005], p.4) by Charles Parsons - Review of Tait 'Provenance of Pure Reason' §2 | |
A reaction: This looks like the classic twentieth century shift in the attitude to axioms. The Greek idea is that they must be self-evident truths, but the Tait-style view is that they are just the first steps in establishing a logical structure. I prefer the Greeks. |
16721 | Changes in secondary qualities are caused by changes in primary qualities [Giles of Orleans] |
Full Idea: Every alteration in secondary qualities is caused by some alteration made in the primary qualities. | |
From: Giles of Orleans (On 'Generation and Corruption' [1270], I.6c) | |
A reaction: Pasnau calls this the 'supervenience' thesis, here with the addition of causation. Was this doctrine retained by Locke and Boyle? |
12709 | Motion is not absolute, but consists in relation [Leibniz] |
Full Idea: In reality motion is not something absolute, but consists in relation. | |
From: Gottfried Leibniz (On Motion [1677], A6.4.1968), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 3 | |
A reaction: It is often thought that motion being relative was invented by Einstein, but Leibniz wholeheartedly embraced 'Galilean relativity', and refused to even consider any absolute concept of motion. Acceleration is a bit trickier than velocity. |