Abstract
Two traditions in action theory offer different accounts of what distinguishes intentional action from mere behavior. According to the causalist tradition, intentional action has certain distinguished causal antecedents, and according to the Anscombian tradition, intentional action has certain distinguished epistemological features. I offer a way to reconcile these ostensibly conflicting accounts of intentional action by way of appealing to "ability-constituting knowledge". After explaining what such knowledge is, and in particular its relationship to inadvertent virtue and knowledge-how, I suggest that, among other things, appealing to ability-constituting knowledge can help us flesh out what it is for an agent's reasons to non-deviantly cause and sustain her purposive behavior.