Anyone familiar with ancient, medieval and early modern philosophy will be aware of the extent to which thinkers in these periods assume that we are possessed of immaterial rational souls. There are, of course, quite significant differences in their understanding of the nature of the soul; but that it exists and that it can be known to exist are rarely if ever doubted. It is, however, one thing to know that something exists, a second thing to be able to demonstrate its existence (from commonly agreed if not exactly indubitable premises), and a third to describe its nature or essence. Writing of the possibility of natural knowledge of God, Aquinas distinguishes two kinds of causal arguments: those in which one reasons from the nature of a thing to its effects, showing why they are as they are; and those in which one reasons from effect to cause. In the case of the former one must already know something of the essence of the agent, but in the case of the latter one might only know effects, and all that can be demonstrated may be that an adequate cause of them must exist. The question arises of reasoning further from the character of the effects to that of the cause, but this is made challenging in the case of reasoning about God since he is also taken to be transcendent of, and absent from, the categories of ordinary predication. Since in the case of the soul, however, there is not the issue of a radical dis-

continuity between the status of cause and effect one may hope for a more proximate description of the soul’s nature. As methodology this should secure some approval from those familiar with scientific reasoning to the character of unobservables, but it is now likely to meet with two contrasting reactions. First, of course, that the very idea of the soul is otiose and perhaps absurd; and second, that to the extent that anything supports a doctrine of the soul it is first-person selfacquaintance, not a causal hypothesis based on observed effects. In what follows I want to consider, somewhat briefly, some classical arguments for the existence of the rational soul as an immaterial and possibly surviving principle of human life,

but also try to understand better the ancient idea that death involves the departure of the soul.