Existentialists were commonly accused of spreading pessimism and nihilism. Those accusations were unjustified and harmful, says the author. They also betray a misunderstanding on the part of the critics. Sartre did not attempt to abolish ethics, but he undertook to create one that would not be constrained by structures of naturalism and supra-naturalism. Human obligations could neither be found in an empirical study of nature, nor in metaphysics, he thought. Our obligations do not arise from our human condition any more than from some theoretical preconceptions about supreme, absolute values. Human ethics can only be grounded in transcendental ontology, said Sartre, as a human response to the world that is susceptible to evaluation but contains no values in itself. It is out task to endow it with meanings.