The study of law left me unsatisfied, because I did not know the aspects of life which it serves. I perceived only the intricate mental juggling with fictions that did not interest me.

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.

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.

I began the study of medicine, impelled by a desire for knowledge of facts and of man. The resolution to do disciplined work tied me to both laboratory and clinic for a long time to come.

Philosophy can only be approached with the most concrete comprehension.