"Suppose Aristotle was right, and the political association really is the highest social good, and we really do stand in relation to the polis as parts to a whole. If so, then we should expect to see that our own excellence is only found in political communities. That might be so. But to observe as much and offer it as evidence for the claim that we are in fact mere parts of a greater whole is a mistake that Aristotle should never have made. After all, among his many other contributions to philosophy, he was the first to have described the fallacy of affirming the consequent."
Aristotle's vision of the collective pursuit of the good through politics has been an inspiration for centuries of communitarians. But it should never be forgotten that attaining this good required, for him, a large population of individuals who were wholly or substantially unfree.
Aristotle took it for granted that the good could only be pursued by a small, elite minority of the population of a city. All others were to labor in their service, and yet they would take no share of the communal benefit that came from politics.
Modern communitarians are very properly shocked and dismayed by this aspect of Aristotle. Yet even our modern and aspirationally egalitarian democracies struggle with a similar problem: There is, in truth, only so much rulership to go around, and if the good consists of civic participation in the polis to the extent that Athenian citizens participated, almost none of us are good. Almost none of us can be.