About life, the wisest men of all ages have come to the same conclusion: it is no good. Always and everywhere one has heard the same sound from their mouths—a sound full of doubt, full of melancholy, full of weariness of life, full of resistance to life. Even Socrates said, as he died: “To live—that means to be sick a long time: I owe Asclepius the Savior a rooster.” Even Socrates was tired of life. What does that prove? What does it demonstrate? At one time, one would have said (and it has been said loud enough by our pessimists): “At least something must be true here! The consensus of the sages must show us the truth.” Shall we still talk like that today? May we? “At least something must be sick here,” we retort. These wisest men of all ages—they should first be scrutinized closely. Were they all perhaps shaky on their legs? tottery? decadent? late? Could it be that wisdom appears on earth as a raven, attracted by a little whiff of carrion?
—Friedrich Nietzsche, Twilight of the Idols.
“The vanity of existence is revealed in the whole form existence assumes; in the infiniteness of time and space contrasted with the finiteness of the individual in both; in the fleeting present as the sole form in which actuality exists; in the contingency and relativity of all things; in continual becoming without being; in continual desire without satisfaction; in the continual frustration of striving of which life consists.”
– Arthur Schopenhauer, On the Vanity of Existence.