Isaiah Berlin's distinction between "negative" and "positive" concepts of liberty has recently been defended on new and interesting grounds. Proponents of this dichotomy used to equate positive liberty with "self-mastery "-the rule of our rational nature over ourpassions and impulses. However, Berlin's critics have made the case that this account does not employ a separate "concept" of liberty: although the constraints it envisions are internal, rather than external, forces, the freedom in question remains "negative" (freedom is still seen as the (...) absence of such impediments). Responding to this development, Berlin's defenders have increasingly tended to identify positive liberty with "self-realization." The argument is that such an account of freedom is genuinely "nonnegative," in that it does not refer to the absence of constraints on action. This essay argues that the claims made on behalf of "freedom as self-realization" cannot withstand scrutiny, and that they fail to isolate a coherent view of liberty that is distinguishable from the absence of constraint. (shrink)