Only then, approaching my fortieth birthday, I made philosophy my life's work.

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

If philosophy is practice, a demand to know the manner in which its history is to be studied is entailed: a theoretical attitude toward it becomes real only in the living appropriation of its contents from the texts.

The community of masses of human beings has produced an order of life in regulated channels which connects individuals in a technically functioning organisation, but not inwardly from the historicity of their souls.

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

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.

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.