 However that issue about rationalisations is decided, two things should be noted. First, in “error cases”—cases when an agent acts on the basis of a falsehood that he believes and treats as a reason for acting—the explanans of a true explanation must be a psychological fact. For instance, the explanation of why Othello kills Desdemona cannot be what he believes, that Desdemona has been unfaithful, but rather the fact that he believes it. This is because explanations are, it is generally thought, factive: a true explanation cannot have a falsehood as its explanans: we cannot say that Othello kills Desdemona because she has been unfaithful when she hasn’t. The second thing to note is that, even if psychologism is right for explanatory reasons (that is, even if all reason explanations cite psychological facts), it does not follow that psychologism is right for motivating reasons because these reasons need not be the same. In other words, if one attends to the distinction between the roles of motivation and explanation that reasons can play, there should be no temptation to move from psychologism concerning explanatory reasons in some or in all cases, to psychologism concerning motivating reasons.