My own being can be judged by the depths I reach in making these historical origins my own.

I discovered that the study of past philosophers is of little use unless our own reality enters into it. Our reality alone allows the thinker's questions to become comprehensible.

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.

Even scientific knowledge, if there is anything to it, is not a random observation of random objects; for the critical objectivity of significant knowledge is attained as a practice only philosophically in inner action.

To decide to become a philosopher seemed as foolish to me as to decide to become a poet.

What makes us afraid is our great freedom in the face of the emptiness that has still to be filled.

As a universal history of philosophy, the history of philosophy must become one great unity.