 Psychologism is very appealing. For it seems right that when an agent acts for a reason, he acts motivated by an end that he desires (an end towards which he has a “pro-attitude”) and guided by a belief about how to achieve that end. Because of this, it is possible to explain his action by citing his desiring and his believing the relevant things. To return to our example, we can explain why Othello kills Desdemona by citing his wanting to defend his honour and his believing that, given that Desdemona has been unfaithful, killing her is the only way to do so. And this sort of explanation in terms of states of belief and desire supports the relevant counterfactuals: had Othello not believed that she had been unfaithful or had he not believed that killing her was the only way to defend his honour, he wouldn’t have killed her, even if he had still wanted to restore his reputation; and had he not cared about his reputation, he wouldn’t have killed her, despite his beliefs about her betrayal and what was necessary to defend his honour. This sort of consideration led to widespread acceptance of the view that explanatory reasons are mental states and, since the latter were not distinguished from motivating reasons, it also led to the view that motivating reasons are mental states.