Andrew Feenberg's work continues critical theory's concern with the way in which capitalism appears, or is experienced, as beyond criticism or challenge. Why or how the social practices involved appear this way is explained in terms of their apparent rationality. While Feenberg does more than most critical theorists to elaborate the conception of rationality involved, the account he gives, in terms of particular resemblances to science, seems at best ad hoc and at worst seems to cede science to positivism. I argue, however, that Feenberg's account of rationality can easily be given an alternative, more ontological, grounding. Some implications of this alternative account are then drawn out, especially in relation to Feenberg's theory of technology.