The will is the key component of Duns Scotus’s moral theory, both because Duns Scotus held (quite uncontroversially) that we are morally responsible only for our free choices and their outcomes and because (more controversially) he thought that most principles detailing what is morally good and what is morally bad depends on God’s free decisions. The key, then, question is how we know contingent practical principles. This essay offers an account of our knowledge of such principles that is (a) consistent with what Duns Scotus says about the relationship of the moral law to the divine will and to human nature, (b) consistent with what he says more generally about our knowledge of contingent truths, and (c) consistent with his actual argumentative practice in dealing with contingent practical principles. The examination of Duns Scotus’s argumentative practice uncovers a third, hitherto unnoticed, sense of ‘natural law’. This essay suggests that the core unifying sense of ‘natural law’ for Duns Scotus is precisely the epistemic status of the precepts of natural law as non-inferentially evident.