Weakness of will and motivational internalism

The unconditional version of motivational internalism says that if an agent sincerely judges that to φ in circumstances C is the best option available to her, then, as a matter of conceptual necessity, she will be motivated to φ in C. This position faces a powerful counterargument according to which it is possible for various cases of practical irrationality to completely defeat an agent’s moral motivation while, at the same time, leaving her appreciation of her moral reasons intact. In this paper, I will argue that weakness of will, as the paradigmatic case of practical irrationality, and all other cases of practical irrationality that feature in standard formulations of this argument do not represent genuine counterexamples to this version of motivational internalism. In this sense, the main aim of this paper is to show that proponents of this internalist position are well justified in their denial of the claim that there are people who are completely unmotivated by their judgments about what is the best option available to them.