Plato – that scourge of the human mind, whom we have to thank for persuading philosophers for 2400 years, and more years to come, that it is a proble… - David Stove

[Popper's skepticism about scientific truth in The Logic of Scientific Discovery is] that kind of reaction, of which the epitome is given in Aesop's fable of the fox and the grapes. The parallel would be complete if the fox, having become convinced that neither he nor anyone else could ever succeed in tasting grapes, should nevertheless write many long books on the progress of viticulture.

A philosopher may try to prove the truth of something he believed before he was a philosopher, but even if he succeeds, his belief never regains the untroubled character, and the settled place in his mind, which it had at first.

The proprietor of a pornographic book shop may be dimly conscious of a debt to the author of Areopagitica, but Milton is the last person he wants to see in his shop.