Abstract
This thesis develops a Neo-Humean, functionalist account of practical rationality and normativity. On this view, principles of practical rationality are grounded in the proper function of our agency, while the normative force of a normative reason in calling for a certain response on our part consists in its capacity to engage the function of that response. This functionalist picture, I contend, undermines three long-held and widely-accepted views about practical rationality and normativity. Contra orthodox Humeanism about practical rationality, the functionalist account shows that the rational principles governing our intention are not limited to instrumental and formal coherence principles. Contra rationalists about the nature of rationality, the functionalist account supports an environmentally-embedded conception of practical rationality and demonstrates that the requirements of practical rationality are not necessary, a priori requirements. Finally, contra externalists about normative reasons for action, the functionalist account reveals that the normative force involved in normative reasons for action is best captured not by externalist considerations, but instead by our intentions or volitional states.