What the Argument Requires

"Thus the Republic, like the Phaedo, rejects the claims of non-philosophers to possess any genuine virtue", Plato's Utopia Recast, p. 43.

What would be necessary, to establish this?

First, one needs to put aside any claims Bobonich has made about the lack of virtue of non-philosophers in the Phaedo, because, as we saw, these claims were not well grounded. We would have to approach the Republic on its own terms.

Second, one would need to show that, when the Republic says things of the form "Philosophers and only philosophers are virtuous", the claim is not meant in an implicitly reduplicated sense; and that it excludes degrees or stages of philosophy and virtue.

Third, one would need to consider the special circumstance (not contemplated in the Phaedo), in which non-philosophers willingly place themselves under the authority of philosophers. One would have to show that, under this special circumstance, non-philosophers do not have 'participated' virtue (as we called it), or that, if they do, Plato thinks that virtue of that sort is in no sense 'genuine' virtue.

Fourth, one would need to consider the various passages in the Republic (and there are many) in which Plato either ascribes virtue to non-philosophers, or says things that imply that non-philosophers have virtue, and show that the most plausible interpretation of these passages, is that Plato would wish to deny that non-philosophers have virtue.

If, as I believe is the case, it would not possible to do these things, and someone who examined the matter closely would be compelled to recognize degrees and stages of virtue among non-philosophers in the Republic--then someone who wanted to claim, nonetheless, that the view of the Republic was radically different from, or incompatible with, that of the Laws, would have to show that the sense in which citizens in the Laws could be virtuous, was radically different from, and incompatible with, the various senses in which non-philosophers in the Republic could be virtuous.

This is what correct attention to method, evidence, and argument would require.