All teaching and all intellectual learning come about from already existing knowledge.

One who faces and who fears the right things and from the right motive, in the right way and at the right time, posseses character worthy of our trust and admiration.

Even when laws have been written down, they ought not always to remain unaltered.

We have no evidence as yet about mind or the power to think; it seems to be a widely different kind of soul, differing as what is eternal from what is perishable; it alone is capable of existence in isolation from all other psychic powers.

Perfect friendship is the friendship of men who are good, and alike in excellence; for these wish well alike to each other qua good, and they are good in themselves.

The good of man is the active exercise of his soul's faculties. This exercise must occupy a complete lifetime. One swallow does make a spring, nor does one fine day. Excellence is a habit, not an event.

A true friend is one soul in two bodies.