Socrates' Last Argument

Abstract

The last argument of Plato's Phaedo has always fascinated philosophers. Though speciously smooth, it is naggingly hard to understand, and persistent failure provokes persistent interest. But the real importance of the argument lies in what it reveals about Plato's metaphysical theory, and about his view of the nature of metaphysical enquiry. If we are to see exactly what is going on, we need a formal analysis of the argument, a precise location of its errors, and some explanation of how Plato came to make them. To be at all plausible an interpretation must be charitable both to Plato and to his commentators. We should show Plato's reasoning to be as systematic as it seems to be, and make his mistakes intelligible; and we should be able to understand the repeated failure of commentators to explain what Plato is doing. I shall argue that the argument is formally valid and displays the systematic application of fundamental principles. Its faults are not logical in a narrow sense, but rest on what seems to us a gross metaphysical confusion. Attribution of such confusion to Plato is not new; but one of the significant features of this argument is that it can be used to justify that attribution beyond reasonable doubt. This ascription of error would nevertheless seem a lapse from charity in interpretation, if we could not make the confusion seem a natural one for Plato to make. Another striking point about this passage is that it actually provides materials for an explanation of the confusion. The source of the difficulty is Plato's mistaken semantic theory, which is all but spelled out here. On the basis of this passage, we can see that the theory of Forms is largely motivated by a concern to make sense of certain semantic assumptions, and many of its faults are traceable to faults in the semantic theory.