Who said “There is no means of proving it is preferable to be than not to be.”?

“Man is the only animal for whom his own existence is a problem which he has to solve.”

“Existence itself does not feel horrible; it feels like an ecstasy, rather, which we have only to be still to experience.”

“One is still what one is going to cease to be and already what one is going to become. One lives one's death, one dies one's life.”

“The cradle rocks above an abyss, and common sense tells us that our existence is but a brief crack of light between two eternities of darkness.”

“I can, therefore I am.”

“Every thought derives from a thwarted sensation.”

“Consciousness is much more than the thorn, it is the dagger in the flesh.”

“The fact that life has no meaning is a reason to live --moreover, the only one.”

“Progress is the injustice each generation commits with regard to its predecessors.”

“It is not worth the bother of killing yourself, since you always kill yourself too late.”

“Criticism is a misconception: we must read not to understand others but to understand ourselves.”