True opinions are a fine thing and do all sorts of good so long as they stay in their place; but they will not stay long. They run away from a man's mind, so they are not worth much until you tether them by working out the reason. Once they are tied down, they become knowledge, and are stable.
PlatoIf in a discussion of many matters ... we are not able to give perfectly exact and self-consistent accounts, do not be surprised: rather we would be content if we provide accounts that are second to none in probability.
PlatoMisanthropy ariseth from a man trusting another without having sufficient knowledge of his character, and, thinking him to be truthful, sincere, and honourable, finds a little afterwards that he is wicked, faithless, and then he meets with another of the same character. When a man experiences this often, and more particularly from those whom he considered his most dear and best friends, at last, having frequently made a slip, he hates the whole world, and thinks that there is nothing sound at all in any of them.
Plato