Knowing means to penetrate through the surface, in order to arrive at the roots, and hence the causes; knowing means to "see" reality in its nakedness. Knowing does not mean to be in the possession of the truth; it means to penetrate the surface and to strive critically and actively in order to approach truth ever more closely.

Love is an active power in man; a power which breaks through the walls which separate man from his fellow men, which unite him with others; love makes him overcome the sense of isolation and separateness, yet it permits him to be himself, to retain his integrity.

Who will tell whether one happy moment of love or the joy of breathing or walking on a bright morning and smelling the fresh air, is not worth all the suffering and effort which life implies.

Ideas become powerful only if they appear in the flesh; an idea which does not lead to action by the individual and by groups remains at best a paragraph or a footnote in a book.

It doesn't matter whether one uses God or doesn't. What matters is which experience a person has.

I am convinced that boredom is one of the greatest tortures. If I were to imagine Hell, it would be the place where you were continually bored.

The quest for certainty blocks the search for meaning. Uncertainty is the very condition to impel man to unfold his powers.