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

Only in those moments when I exercise my freedom am I fully myself.

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

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.

The more determinedly I exist, as myself, within the conditions of the time, the more clearly I shall hear the language of the past, the nearer I shall feel the glow of its life.

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.

Only a development of thought achieved through the self-education of the whole man can prevent any body of thought whatsoever from becoming a poison; can prevent enlightenment from becoming an agent of death.