There is no sun without shadow, and it is essential to know the night.

This heart within me I can feel, and I judge that it exists. This world I can touch, and I likewise judge that it exists. There ends all my knowledge, and the rest is construction. (...) Forever I shall be a stranger to myself.

There is but one truly serious philosophical problem, and that is suicide. Judging whether life is or is not worth living amounts to answering the fundamental question of philosophy.

We lead a difficult life, not always managing to fit our actions to the vision we have of the world. (And when I think I have caught a glimpse of the color of my fate, it flees from my gaze.) We struggle and suffer to reconquer our solitude. But a day comes when the earth has its simple and primitive smile. Then, it is as if the struggles and life within us were rubbed out. Millions of eyes have looked at this landscape, and for me it is like the first smile of the world. It takes me out of myself, in the deepest meaning of the expression. It assures me that nothing matters except my love, and that even this love has no value for me unless it remains innocent and free. It denies me a personality, and deprives my suffering of its echo. The world is beautiful, and this is everything. The great truth which it patiently teaches me is that neither the mind nor even the heart has any importance. And that the stone warmed by the stone or the cypress tree swelling against the empty sky set a boundary to the only world in which "to be right" has any meaning: nature without men. This world reduces me to nothing. It carries me to the very end. Without anger, it denies that I exist. And, agreeing to my defeat, I move toward a wisdom where everything has already been conquered -- except that tears come into my eyes, and this great sob of poetry which swells my heart makes me forget the truth of the world.

It was as if that great rush of anger had washed me clean, emptied me of hope, and, gazing up at the dark sky spangled with its signs and stars, for the first time, the first, I laid my heart open to the benign indifference of the universe.
To feel it so like myself, indeed, so brotherly, made me realize that I'd been happy, and that I was happy still. For all to be accomplished, for me to feel less lonely, all that remained to hope was that on the day of my execution there should be a huge crowd of spectators and that they should greet me with howls of execration.

The evil that is in the world almost always comes from ignorance, and good intentions may do as much harm as malevolence if they lack understanding.