Terrence Kelly argues for a theory of practical rationality to explain and handle the issue of residential segregation in the United States. Kelly claims that theories of "racism as irrational" and rational choice are not explanatorily adequate in this regard. I argue that the theory of practical rationality is also not adequate because by allowing agents to offer accounts of their calculated behaviour, it allows little appraisal of the behaviour itself. I argue instead that better explanations could be offered by (...) appeal to ethical theory. Key Words: residential segregation • trust • practical rationality • ethical theory. (shrink)