In ‘The World of Universals’, Chapter IX of The Problems of Philosophy, Russell writes: ‘Such entities as relations appear to have a being which is in some way different from that of physical objects, and also different from that of minds and from that of sense-data. In the present chapter we have to consider what is the nature of this kind of being … The problem with which we are now concerned is a very old one, since it was brought into philosophy by Plato. Plato’s ‘theory of ideas’ is an attempt to solve this very problem, and in my opinion it is one of the most successful attempts hitherto made … The way the problem arose for Plato was more or less as follows. Let us consider, say, such a notion as justice. If we ask ourselves what justice is, it is natural to proceed by considering this, that, and the other just act, with a view of discovering what they have in common. They must all, in some sense, partake of a common nature, which will be found in whatever is just and in nothing else. This common nature, in virtue of which they are all just, will be justice itself, the pure essence the admixture of which with facts of ordinary life produces the multiplicity of just acts. Similarly with any other word which may be applicable to common facts, such as ‘whiteness’ for example. The word will be applicable to a number of particular things because they all participate in a common nature or essence. This pure essence is what Plato calls an ‘idea’ or ‘form’.’ (p. 80)
Russell’s account of Plato’s ‘theory of ideas’ or ‘forms’ closely corresponds to Parmenides’ conjecture in the Parmenides of how the young Socrates conceived his theory of Forms. Socrates asks Zeno: ‘Do you not acknowledge that there is, alone by itself, a certain Form of similarity, and an opposite to it, that of dissimilarity, and that of these, being two, you and I and all the other things get a share?’ (128e6-129a3) – Parmenides: ‘Do you think, as you say, that there are certain Forms, of which these other things having a share get their names? As for example, things that get a share of similarity become similar, of largeness large, of beauty and justice beautiful and just? (130e5-131a2) … I think that you came to think that each Form is one from the following; when many things appear to you to be large, there seems to be one Form perhaps which is the same as you look on all of them, whence you believe that the large is one.’ (132a1-4)
It is a historical paradox that Plato’s theory of Forms became identified with the theory of young Socrates, which Parmenides exposed to criticism that Socrates was unable to parry, and so was left in a state of philosophic ignorance, unable to view the Forms as entities of which he had knowledge, and unable to reject them. And so we find him on his last day, in the Phaedo, referring to the Forms as entities which we are reminded of by things around us, entities which we reminisce (72e2-75b2), but which we do not truly know (76b5-c4).
There is a profound contrast between the provenance of Socrates’ Forms in the Parmenides and in the Phaedo. In the Parmenides, as Parmenides conjectured, when many things appeared to Socrates to be large, there seemed to him to be one Form which was the same as he looked on all of them, whence he believed that the large was one, and so with all other Forms he contemplated; the young Socrates derived the Forms from things perceived by our senses. In the Phaedo Socrates contemplates the ‘equal itself’ of which all sensible things we call equal remind us, falling short of it.
In the Parmenides Parmenides ends his criticism of Socrates’ Forms viewed as paradigms with the words: ‘So it is not by similarity that other things participate in the Forms, but one must look for something else by which they participate (133a5-6).’ Socrates in the Phaedo appears to have this observation in mind when he insists that we are reminded of the ‘equal itself’ by equal things we see around us, the equal itself being either similar to them or dissimilar (ȇ homoiou ontos toutois ȇ anomoiou, 74c11).
Russell published The Problems of Philosophy in 1912. In 1911 John Burnet, the editor of the Oxford edition of Plato and arguably the greatest Platonic scholar in the English speaking world of all times, in the ‘Introduction’ to his edition of Plato’s Phaedo passionately pleads against the dominant theory that the Forms were conceived by Plato several years after Socrates’ death and for the first time presented in the Phaedo: ‘I cannot bring myself to believe that he [Plato] falsified the story of his master’s last hours on earth by using him as a mere mouthpiece for novel doctrines of his own.’ (p. XI-XII) Burnet’s views – Burnet notes that in his Early Greek Philosophy he has shown ‘that the Parmenides is accurate in its historical setting and involves no philosophical anachronism’ (note 2 on p. XI) – were rejected. A whole section of the Sixth International Congress of Philosophy, held in 1927 in New York, was devoted to the condemnation of his views. The section began with a brief introductory preamble:
‘The first paper in Division D, Section I, was to have been read by John Burnet (Edinburgh), but sudden illness made Professor Burnet’s presence at the Congress impossible. In Professor Burnet’s absence, W. D. Ross (Oxford) spoke briefly, summarizing Professor Burnet’s views on the Socratic and Platonic elements in the doctrine of Plato’s dialogues.’
What followed was a chorus of contempt in which the great Platonic scholars of those days joined forces under the chairmanship of G. S. Brett (Toronto) and P. E. More (Princeton): R. C. Lodge (Manitoba), Leon Robin (Sorbonne), Paul Shorey (Chicago), W. A. Heidel (Wesleyan). The printed Proceedings do not give W. D. Ross’ summary of Burnet’s views, but since he is the only scholar who in his edition of Aristotle’s Metaphysics brings a strong argument against Burnet’s views, it may be safely assumed that not a word in support of Burnet was uttered on that occasion.
Ross showed that Aristotle viewed Plato as the author of the theory of Forms or Ideas, as Ross prefers to call Plato’s essences. In Metaphysics A 987a29-b9 Aristotle says:
‘After the systems we have named came the philosophy of Plato, which in most respects followed these thinkers [i.e. the Pythagoreans], but had peculiarities that distinguished it from the philosophy of the Italians. For, having in his youth first become familiar with Cratylus and the Heraclitean doctrines (that all sensible things are ever in a state of flux and there is no knowledge about them), these views he held in later years. Socrates, however, was busying himself about ethical matters and neglecting the world of nature as a whole but seeking the universal in these ethical matters, and fixed thought for the first time on definitions; Plato accepted his teachings, but held that the problem applied not to sensible things but to entities of another kind – for this reason, that the common definition could not be a definition of any sensible thing, as they are always changing. Things of this other sort, then, he called Ideas, and sensible things, he said, were all named after these, and in virtue of a relation to these.’ (Tr. Ross)
In Metaphysics M 1078b9-32 Aristotle says:
‘Now, regarding the Ideas, we must first examine the ideal theory itself, not connecting it in any way with the nature of numbers, but treating it in the form in which it was originally understood by those who first maintained the existence of Ideas (hoi prȏtoi tas ideas phȇsantes einai). The supporters of the Ideal theory were led to it because on the question about the truth of things they accepted the Heraclitean sayings which describe all sensible things as ever passing away, so that if knowledge or thought is to have an object, there must be some other and permanent entities, apart from those which are sensible; for there could be no knowledge of things which were in a state of flux. But when Socrates was occupying himself with the excellences of character, and in connection with them became the first to raise the problem of universal definition … Socrates did not make the universals of definitions exist apart, they, however, gave them separate existence, and this was the kind of thing they called Ideas.’ (Tr. Ross)
Ross notes that in the Metaphysics M passage Plato is not named, but that the reference in both passages to the influence of Heracliteanism, as well as the identical way in which Socrates is introduced in both passages as the mediating influence, and the identity, but for the change of number, of the final statement in both these passages, show that ‘those who first maintained the existence of the Ideas’ in Metaphysics M means just Plato. (See W. D. Ross, Aristotle’s Metaphysics, Clarendon Press, Oxford, 1924, vol. I, pp. xxxiii-xxxvi.
Pace Ross, Aristotle does not refute Burnet’s contention that the theory of Forms is of Pythagorean origin. For if we take the Parmenides as a reliable historical testimony – as Burnet did and as I have argued in ‘Plato’s defence of the Forms in the Parmenides’, which I put on my website this morning – then neither the Pythagoreans with their version of the theory nor Socrates could maintain the Forms face to face with Parmenides’ destructive propaedeutic discussion of the forms. The Forms had to wait for Plato, for only he could maintain the Forms in spite of Parmenides’ criticism.