In the first part of this paper, it is shown in what a conspicuous way the story of Oedipus illustrates a central feature of human agency, namely, that any action may turn out to be of quite another nature than it was thought, or intended, to be. The story of Oedipus provides further insight on comparing ancient and modern man's outlook on agents, their actions, and the world. It emerges that we moderns are lacking an adequate conceptual scheme for an understanding of human agency that lives up to the demands of an enlightened picture of the world. This problem should be one of the central topics of a philosophical theory of action, rather than the misguided questions, e.g. about the causal nature of reasons for action that are usually treated there. Accordingly the sketch of a critique of action theory is being offered.