Full Idea
Our lack of sureness in the senses is shown if we take two colours, back and white, and pour one into the other drop by drop, we are unable to distinguish the gradual alterations although they subsist as actual facts.
Gist of Idea
We reveal unreliability in the senses when we cannot discriminate a slow change of colour
Source
report of Anaxagoras (fragments/reports [c.460 BCE]) by Sextus Empiricus - Against the Logicians (two books) I.090
Book Reference
Sextus Empiricus: 'Against the Logicians', ed/tr. Bury,R.G. [Harvard Loeb 1997], p.47
A Reaction
[Sextus calls Anaxagoras 'the greatest of the physicists'] I'm not sure what this proves. People with bad eyesight can distinguish very little, but that doesn't prove scepticism. And there are things too small for anyone to see.