I know what I can know, and am not troubled about what I cannot know.

The schools must fashion the person, and fashion him in such a way that he simply cannot will otherwise than what you wish him to will.

Not alone to know, but to act according to thy knowledge, is thy destination,--proclaims the voice of my inmost soul. Not for indolent contemplation and study of thyself, nor for brooding over emotions of piety,--no, for action was existence given thee; thy actions, and thy actions alone, determine thy worth.

What sort of philosophy one chooses depends, therefore, on what sort of man one is; for a philosophical system is not a dead piece of furniture that we can reject or accept as we wish; it is rather a thing animated by the soul of the person who holds it.

A man can do what he ought to do; and when he says he cannot, it is because he will not.

We do not act because we know, but we know because we are called upon to act; the practical reason is the root of all reason.

The person who doubts there is an external world does not need proof: he needs a cure.