This brings me to a fourth thing I do not so much import from Aristotle as find him hospitable to, namely a philosophical psychology which runs counter to the prevailing contemporary view. In contemporary philosophy of action, there is a fervid debate about whether any intentional action must be prompted in part by a desire, or whether it is possible to be moved to action by a belief-such as the belief that doing so-and so is morally required-alone. The debate all takes place against the background of the assumption that belief and desires are as different as gold and oxygen, and usually also the assumption that the distinction between the rational and the non-rational is equally hard and fast. But Aristotle is happy to describe ‘choice’ (prohairesis) as either desiderative intellect or intellectual desire; it belongs to both the cognitive and the conative faculties and is not to be broken down into two bits, a belief and a desire.
Moreover, when he describes the soul as ‘part rational, part irrational’, he does not think it matters to which part we assign the desiderative. The ‘vegetative’ part (the cause of nutrition and growth in living things) is definitely irrational; and the theoretical is definitely rational. But the desiderative can be regarded as irrational, because it can run counter to reason, or as rational, because it is receptive to reason. There is no answer to the question ‘Is it rational or irrational tout court?’; all there is to be said is that it is irrational in this way and rational in that. To anyone sympathetic to the writings of the later Wittgenstein, such rejections of clear-cut distinctions in philosophical psychology are as natural and necessary as breathing. Such philosophers are in a minority at the moment, and it is no part of my brief in this book to try to convert the philosophical world to the minority view, much as I would like to do so. But it is still worth coming clean about it at the outset, to remove one further stumbling block. I have found when teaching virtue ethics to graduate students, or discussing papers by, in particular, Anscombe, Foot, and McDowell with fellow philosophers, that what often blocks understanding is the unconscious assumption that everyone shares the view that, for example, beliefs and desires are natural kinds, or that a reason is a belief/desire pair that causes an action, or that all mental states are brain states-or, more generally, that philosophy is supposed to uncover or construct the foundations of our thought. Struggling to square these assumptions with what is said, the audience finds what is said deliberately obscure or willfully incomplete, or inconsistent, or open to such blindingly obvious objections that they think they cannot have understood. Sometimes-not always, of course-the cloud lifts if one says, ‘But you don’t believe that so-and-so if you’re Wittgensteinian.’ What follows then is not necessarily agreement, but at least an understanding of just where the disagreement lies.