both 2a and 2b are consistent with s-change, but that 2a is not consistent with a-change since existence is not a predicate. That is, we can consistently substitute "exists" into the s-change formula:
X s-changes iff at time t1 X exists and at time t2 X does not exist, and X itself is not in the same condition at t2 as it was at t1.
Since Irwin's formulations are already in the predicate form, it is easy to see that 2b is consistent with both s-change and a-change. However, there is the concern that a-change is not genuine change at all, since it apparently views relative change as intrinsic change. That is, the object is seen as changing merely because its situation can be perceived to change or because opposite properties can be attributed to it due to differing perspectives. The object itself is mistakenly taken as cause for these apparent contradictions, when in actuality, we have no grounds for inferring this. In any event, it seems Plato counts a-change as genuine.63 This is what is important for interpreting Bk. V and evaluating the existential and predicative positions.
What can we conclude from this discussion of change and the existential and predicative formulae? I argue that, since Plato does not clearly distinguish between s- and a-change, since he does not supply any qualifying descriptions of the change of sensibles in Bk. V, and because both the existential and predicative interpretations are both consistent with at least one of the possible conceptions of change accepted by Plato, we cannot readily exclude either the existential or predicative positions from being equally possible and legitimate readings of Bk. V.
We have discussed the inherent ambiguity of einai. The application of the existential or predicative form to the given language is a difficult business, since, while we can distinguish between the meanings of the existential and predicative uses, Plato, and the language he has used to express the correlation of faculties and their respective objects in Bk. V, does not make distinctions between these different meanings for us. We can propose models and formulae that Plato might have been intending and argue about which reading is better philosophically; but, I argue it is difficult to project specific, detailed interpretations onto a systematically ambiguous text.
H.F. Cherniss has argued that the universal scope of Plato's philosophical system is an attempt to respond comprehensively and coherently to various ethical, epistemological, and ontological problems.
The phenomena for which Plato had to account were of three kinds, ethical, epistemological, and ontological. [...] The dialogues of Plato, I believe, will furnish evidence to show that he considered it necessary to find a single hypothesis which would at once solve the problems of these several spheres and also create a rationally unified cosmos by establishing the connection among the separate phases of experience.64
An apparent side effect of this universal project is (in its appeal to complete generality) vague, ambiguous expressions that are difficult to interpret. I tend to think, and our discussion of Bk. V should illustrate this, that perhaps we are not entirely justified in attributing specifics to Plato that he himself does not explicitly indicate. We run the risk of reading details into a philosophical system that must often appeal to the most general expression in order to deal with the universal scope it has set for itself.
Vlastos submits that Plato would have been better off with a "kinds-of-reality" theory rather than a degrees of reality theory. It is hoped that we have shown the possibility that Plato might have intended a kinds-of-reality theory and that this ontology serves as the basis for predicative expression. Thus analysis should indicate the possibility that perhaps both the existential and predicative models were operating together in his mind, resulting in the ambiguity and paradoxical language we find in the Republic. At the least, we have shown that both the existential and predicative accounts of the objects of the faculties of knowledge, opinion, and ignorance can be consistently ascribed to the text. I fail to see why we could not read the text either way, or even conclude that both models are working together, at the same time. Stranger things have been attributed to Plato.
3R. 515d, 585b-e.
6R. 477a, 478d, 479d. Cf. also "the really real reality." Phaadrus 247c.
7This by no means exhausts the possible readings. The veridical reading is another possible reading. This is the interpretation advanced by Gail Fine in "Knowledge and Belief in Republic V." Archiv für Geschichte der Philosophie 60 (1978): 121-39. Fine argues that "if we can find a better argument consistent with the text, we should prefer it" and asserts that the veridical interpretation, which does