Single Idea 7401

[catalogued under 12. Knowledge Sources / B. Perception / 2. Qualities in Perception / d. Secondary qualities]

Full Idea

Galileo argued that there is no such thing as heat (and hence also as colour) in the external world, so there is no reason to conclude from colour-blindness that we cannot know the truth about the world.

Gist of Idea

Heat and colour don't exist, so cannot mislead about the external world

Source

report of Galileo Galilei (Il Saggiatore ('The Assayer') [1623]) by Richard Tuck - Hobbes Ch.1

Book Reference

Tuck,Richard: 'Hobbes: a very short introduction' [OUP 2002], p.21


A Reaction

This key idea, taken up by Gassendi, Descartes and Locke, seems to me to be one of the most important (and, in retrospect, rather obvious) facts ever worked out by the human mind. Why does anyone still doubt it?