 Many of those who reject expressivist accounts would endorse some variety of realism about the subject matter of practical reason. The basic commitment of realism in this domain is the idea that there are facts of the matter about what we have reason to do that are prior to and independent of our deliberations, to which those deliberations are ultimately answerable. Realists picture practical reason as a capacity for reflection about an objective body of normative truths regarding action (Skorupski 2010, Parfit 2011, Scanlon 2014). An alternative approach—different both from realism and from the kind of expressivism sketched above—is constructivism (Korsgaard 1997, Street 2008, Street 2010). This approach denies that practical reason is a capacity for reflection about an objective domain of independent normative facts; but it equally rejects the expressivist’s naturalistic suspicion of normativity.  According to the constructivist, practical reason is governed by genuine normative constraints, but what makes these constraints normative is precisely their relation to the will of the agents whose decisions they govern. The principles of practical reason are constitutive principles of rational agency, binding on us insofar as we necessarily commit ourselves to complying with them in willing anything at all. The realm of the normative, on this approach, is not pictured as a body of truths or facts that are prior to and independent of the will; rather, it is taken to be ‘constructed’ by agents through their own volitional activity.