The history of philosophy is not, like the history of the sciences, to be studied with the intellect alone. That which is receptive in us and that which impinges upon us from history is the reality of man's being, unfolding itself in thought.

A scientific approach means knowing what one knows and what one doesn't. Absolute or complete knowledge is unscientific.

What is meaningful cannot in fact be isolated…. We achieve understanding within a circular movement from particular facts to the whole that includes them and back again from the whole thus reached to the particular significant facts.

Man is always something more than what he knows of himself. He is not what he is simply once and for all, but is a process; he is not merely an extant life, but is, within that life, endowed with possibilities through the freedom he possesses to make of himself what he will by the activities on which he decides.

The great philosophers and the great works are standards for the selection of what is essential. Everything that we do in studying the history of philosophy ultimately serves their better understanding.

Reason is like an open secret that can become known to anyone at any time; it is the quiet space into which everyone can enter through his own thought

Philosophy as practice does not mean its restriction to utility or applicability, that is, to what serves morality or produces serenity of soul.