Conversation with a friend will only bear good fruit of knowledge when both think only of the matter under consideration and forget that they are friends.
For knowing is spoken of in three ways: it may be either universal knowledge or knowledge proper to the matter in hand or actualising such knowledge; consequently three kinds of error also are possible.
Knowing things halfway is a greater success than knowing things completely: it takes things to be simpler than they really are andso makes its opinions more easily understandable and persuasive.
Man, being the servant and interpreter of Nature, can do and understand so much and so much only as he has observed in fact or thought of the course of nature; beyond this he neither knows anything nor can do anything.
They assembled together and dedicated these as the first-fruits of their love to Apollo in his Delphic temple, inscribing there those maxims which are on every tongue- 'know thyselP and 'Nothing overmuch.'
If we will not interfere with our thought, but will act entirely, or see how the thing stands in God, we know the particular thing, and every thing, and every man.
But this is that which will dignify and exalt knowledge: if contemplation and action be more nearly and straitly conjoined and united together than they have been: a conjunction like unto that of the highest planets, Saturn, the planet of rest and contemplation, and Jupiter, the planet of civil society and action.
We have no organ at all for knowledge, for truth: we know (or believe or imagine) precisely as much as may be useful in the interest of the human herd, the species: and even what is here called usefulness is in the end only a belief, something imagined and perhaps precisely that most fatal piece of stupidity by which we shall one day perish.