Socrates proposes in Republicv–vi that political rule should be put in the hands of philosophers, provided that they also ‘in no way fall short of [non-philosophers] in experience, nor rank after them in any other part of excellence’ (vi, 481d6–7). The question, especially for Glaucon, is what philosophers will bring to the task of ruling that non-philosophers cannot; and that will also be the question for the present chapter. It will turn out that there are two answers, one more sophisticated, one less so; the latter is nearer the surface, and more immediately persuasive for Socrates' (Plato's) immediate audience, while the former is truer to his real position – which will be the subject of a separate chapter (chapter 8).

Socrates begins his answer to Glaucon's question – why philosophers? – in that argument which I discussed in the preceding chapter, at the end of Book v. As we saw, his starting-point is that philosophers, lovers of wisdom, are distinguished as such by the fact that they love all aspects of wisdom, something which sets them apart from others who seem to love every aspect of something, like the ‘sight-lovers’, who are actually quite picky about what they love. The latter don't even recognize the very thing they should really be loving (beauty itself); they only recognize the many beautiful particulars, which they misidentify as beauty.