Optimism is not only a false but also a pernicious doctrine, for it presents life as a desirable state and man's happiness as its aim and object. Starting from this, everyone then believes he has the most legitimate claim to happiness and enjoyment. If, as usually happens, these do not fall to his lot, he believes that he suffers an injustice, in fact that he misses the whole point of his existence.
Arthur SchopenhauerPhilosophy ... is a science, and as such has no articles of faith; accordingly, in it nothing can be assumed as existing except what is either positively given empirically, or demonstrated through indubitable conclusions.
Arthur Schopenhauer