On exploring normative constraints in new situations

Philip Pettit's ethnocentric account of rule-following is elaborated and de fended in this paper as basically a story about the capacity to reason orga nized around largely implicit assumptions about what is and what is not nor mal. It is argued that this account can be insightfully used to elucidate t he practical reasoning of agents confronted with the normative indeterminac y that seems to be characteristic of radically new situations. It is shown that practical reasoning consists to a large extent in the capacity to arti culate, specify, and evaluate implicit assumptions about what is and what i s not normal. One corollary of this account of practical reason is investig ated in some detail: the predominant role of intrapersonal divergence of ha bits in reasoning about an apparent normative indeterminacy and the related , merely criteriological role of convergence with respect to determining th e right rules to follow.