Abstract
In this paper, I describe a hitherto overlooked kind of practical irrationality, which I call irrational option exclusion. An agent who suffers from this problem does not merely fail to act on her best judgement – she fails to realize that the superior action is even an option for her. I furthermore argue that this kind of irrationality is serious enough to undermine moral responsibility. I show that an agent suffering from this problem has compromised reasons-responsiveness, does not really express her will through action, and has a hard time doing otherwise; thus, from the standpoint of several popular moral responsibility theories, we ought to conclude that her responsibility is at the very least diminished.