IV.—FORMS AS CAUSES IN THE PHAEDO

Abstract

I WISH to discuss two questions in this paper: (a) What sort of explanation did Plato think he was proposing in the Phaedo when he offered explanation in terms of the theory of Forms as an alternative to earlier methods of scientific explanation? (b) What relation does this kind of explanation bear to Aristotle's explanation in terms of formal causes? The first important point is that Plato's method is of quite unrestricted application. It arises out of dissatisfaction with certain hitherto accepted ways of answering questions beginning ' Why ...? ' At 96a 8-9 Socrates says that it seemed to him a wonderful thing to know the causes of each thing, why it comes to be and why it perishes and why it is. Mention of coming to be and perishing indicates that Socrates' interests included natural change (as is confirmed by his examples, e.g. inquiry into the causes of the generation of animals) and in general all phenomena which fall within the scope of natural science. But other questions are involved too: besides his scientific examples Socrates cites such questions as 'Why is ten greater than eight? ' and ' When one unit is added to another, is it one of the units which becomes two, and, if so, which one, or do both units become two? ' The latter question, at least, is clearly a conceptual question, in that it has to be answered by considering the meanings of terms used in talking about numbers, and by considering the logical relations of propositions formed from those terms. The first question ' Why is ten greater than eight?' is less easy to characterise; it is clearly not an empirical question, but it is not recognisably a conceptual one either. It just isn't clear what question is meant to be posed in these words. But the answer which Socrates says he had held, and which he later rejected, that ten is greater than eight because it contains two units more than eight, indicates that the question is to be interpreted as 'What feature of the number ten explains or accounts for its being greater than eight? ' Thus interpreted the question is a conceptual one, to be answered by showing how the relation between the numbers ten and eight is a particular case of the succession of numbers which constitutes the natural number system. The method of explanation in terms of Forms, therefore, provides answers to all questions of causation in the natural world, and to all conceptual questions which can be introduced by the word 'Why . . .? ' It is, therefore, anachronistic to