Sartre carefully differentiates himself from eighteenth-century atheists like “Diderot, Voltaire, and even Kant” who reject the existence of God but replace religious moral codes with moral codes based on particular views of human nature. For Sartre, these atheists are not existentialists because they do not take the obsolescence of belief in God seriously enough to rethink their moral beliefs. The early atheist belief in “human nature” would still leave morality outside individuals’ control.