 Is one obliged to always follow one’s conscience? It depends, since conscience is fallible. If what it dictates is in accordance with God’s will, then one is obliged to follow it on pain of eternal damnation. If erroneous—if what it dictates is contrary to the divine will—as is sometimes the case when applying basic deontological principles, then conscience does not bind. Rather, the agent has an obligation to correct the error in order to bring his conscience into line with the natural law. If he does not, and follows his erroneous conscience, he commits a mortal sin. “It is clear that conscientia always either binds us to do what it tells us, or binds us to change it” (commentary on the Sentences 2.39: a. 1, q. 3; Potts trans. 1980: 114–115). Obviously, then, the intellect plays an important role in achieving happiness given its possession of conscience. But what of the will? Does it not have an equally important role to play in the moral life? Yes: in its possession of synderesis. In line with tradition, Bonaventure calls synderesis the “spark of conscience” (commentary on the Sentences 2.39: a. 2; McGrade trans. 2001: 186). He breaks with tradition, however, in arguing that it inheres in the will rather than in the intellect. Indeed synderesis, for Bonaventure, is precisely the counterpart of conscience insofar as the will, like the intellect, has an innate inclination towards the moral (as opposed to the useful) good. In the case of the intellect this disposition takes the form of the “natural light” of conscience that apprehends the first principles of the natural law; in the case of the will, it takes the form of synderesis: a “natural bias” towards desiring the moral good. There is one sense, however, in which synderesis is not exactly analogous to conscience. While it looks very much like a habit, synderesis is rather, according to Bonaventure (presumably following Philip the Chancellor), a habit-like power of the soul (commentary on the Sentences 2.39: a. 2, q. 1; Potts trans. 1980: 116–117).