In this short paper I examine whether obtaining the capability to change practice can be solely achieved through reflective action research, and how. I take as our framework of analysis that offered by Aristotelian thought, especially in the discussion of powers and potential. I conclude that action research as a way of changing practice cannot be only deliberative, but must be based on learning new, propositional knowledge. This is needed so that reflecting, as understanding, on existing practices can be better realised and, importantly, augmented by new capabilities. This may support the idea of continued professional learning taking priority over reflective practice in reaching and maintaining professional mastery.