"A subject interests me and holds my attention only so long as it presents me with difficulties, only so long as I am at odds with it and have, as it were, to struggle with it; but once I have mastered it I hurry on to something else, to a new subject; for my interest is not confined to any particular field or subject; it extends to everything human. This does not mean that I am an intellectual miser or egoist, who amasses knowledge for himself alone; by no means! What I do and think for myself, I must also think and do for others. But I feel the need of instructing others in a subject only so long as, while instructing others, I am also instructing myself."

“What man calls Absolute Being, his God, is his own being. The power of the object over him is therefore the power of his own being. Thus, the power of the object of feeling is the power of feeling itself; the power of the object of reason is the power of reason itself; and the power of the object of will is the power of will itself.”

“Religion is indeed essential to or innate in man, but … this is not the religion of theology or theism, not an actual belief in God, but solely the religion that expresses nothing other than man’s feeling of finiteness and dependency on nature. … I distinguish religion from theism, the belief in a being distinct from nature and man. … Today theism, theology, the belief in God have become so identified with religion that to have no God, to theological being, is considered synonymous with having no religion. But here we deal with the original elements of religion. It is theism, theology, that has wrenched man out of his relationship with the world, isolated him, made him into an arrogant self-centered being who exalts himself above nature. And it is only on this level that religion becomes identified with theology, with the belief in a being outside and above nature as the true God. Originally religion expressed nothing other than man’s feeling that he is an inseparable part of nature or the world.”

“Christianity set itself the goal of fulfilling man’s unattainable desires, but for that very reason ignored his attainable desires. By promising man eternal life, it deprived him of temporal life, by teaching him to trust in God’s help it took away his trust in his own powers; by giving him faith in a better life in heaven, it destroyed his faith in a better life on earth and his striving to attain such a life. Christianity gave man what his imagination desires, but for that very reason failed to give him what he really and truly desires.”

“Can any good come out of Nazareth?" This is always the question of the wiseacres and the knowing ones. But the good, the new, comes from exactly that quarter whence it is not looked for, and is always something different from what is expected. Everything new is received with contempt, for it begins in obscurity. It becomes a power unobserved.”

“I have always taken as the standard of the mode of teaching and writing, not the abstract, particular, professional philosopher, but universal man, that I have regarded man as the criterion of truth, and not this or that founder of a system, and have from the first placed the highest excellence of the philosopher in this, that he abstains, both as a man and as an author, from the ostentation of philosophy, i.e., that he is a philosopher only in reality, not formally, that he is a quiet philosopher, not a loud and still less a brawling one.”

“To theology, … only what it holds sacred is true, whereas to philosophy, only what holds true is sacred.”