Men who are lovers of wisdom [i.e., philosophers] must be inquirers into many things.

The waking have one common world, but the sleeping turn aside each into a world of his own

Opposition brings concord. Out of discord comes the fairest harmony.

Things of which there is sight, hearing, apprehension, these I prefer.

Thinking is a sacred disease and sight is deceptive.

Abundance of knowledge does not teach men to be wise.

Those unmindful when they hear, for all they make of their intelligence, may be regarded as the walking dead.