"Man is the only animal who does not feel at home in nature, who can feel evicted from paradise, the only animal for whom his own existence is a problem that he has to solve and from which he cannot escape. He cannot go back to the prehuman state of harmony with nature, and he does not know where he will arrive if he goes forward. Man's existential contradiction results in a state of constant disequilibrium. This disequilibrium distinguishes him from the animal, which lives, as it were, in harmony with nature."