Recent reconstructions of Heidegger's thoughts on ethics have a curious paradoxical feature. On the one hand, Heidegger, particularly in his Aristotle lectures of the 1920s, offers a view of practical reason on which Dasein has its “moral knowledge” in a fully perceptual, non-cognitive way. This generally sets Heidegger in opposition to the whole business of principled moral justification before the fact. On the other hand, the literature is peppered with what appear to be principled denunciations of immorality—particularly violations of other (...) Dasein—grounded in the analytic of Dasein. To see human life as having a stable ergon (“business” or “function”), with certain broad tasks to pursue and vices to avoid, is not necessarily counter-Aristotelian; on the contrary, it is basic to the kind of Aristotelianism Husserl pursued in his own lectures on ethics. Here I set Heidegger's Aristotelian model of practical reason amid the competing, though similar, Aristotelianisms of John McDowell and Husserl, which differ on their handling of the human ergon. I conclude that Heidegger's views on practical reason and moral knowledge certainly constrain and very much alter the business of moral justification, but they do not precisely rule it out. (shrink)