Can Plato's Republic Actually Get Off The Ground?

Question

I know that Plato's Republic isn't supposed to be taken as a concrete, feasible guide on how to create such a society, and that it's more of a discussion of what an ideal society might be and why that is. He glosses over quite a lot of the details of how something could be implemented in practice.

But something bothers me about it. Right at the beginning, when the new republic is established, Plato says that it's necessary to banish everyone over the age of ten (because their minds will have the old society's corruption ingrained into them), and start afresh with those children, whose minds are still receptive to the changes he wants to make.

Here's the problem: How does he intend to support a society consisting only of children? Who will rule that society - him? That's inherently flawed as he himself will be as corrupted by the old society as the people he banished. What about infrastructure? There will need to be farmers, doctors, etc. Children can't do these things as effectively as experienced adults, so there will inevitably need to be assistance from the types of people who were banished, thus corrupting the new society.

How can his republic even get off the ground?

Answer 1

Welcome, Touchdown.

I think the passage to which you refer is not exactly 'Right at the beginning' but occurs at the end of Rep. VII.541a:

Let them send everyone in the city over the age of ten into the countryside. Then they can isolate these people's children from the values they hold at the moment - their parents' values - and bring the children up according to their own customs and laws, which are of the kind we described earlier. Don't you agree that this will be the quickest and simplest way for the city and regime we were talking about to come into being, making itself happy and bringing a large number of benefits to the nation in which it originates?' (Plato, The Republic, tr. T. Griffith, Cambridge: Cambridge University Press, 2-15: 251.)

...not from no city to ideal city

We need to consider what city (polis) Plato has in mind here. He is thinking not of the ideal city that that he has constructed in imagination (no existing city) but of an actual city that might be converted to rule by philosophers. The children of this city are to be educated 'when true philosophers [oi hos aletethos philosophoi] - it might be a number of them - become rulers in our city' (Rep. VII.540d; Griffith: 251).

... but to ideal city from actual city

'Our city' - the existing city which has, against the odds, come to be ruled by philosophers. Such a city is a bare possibility and is the only feasible way in which 'our ideas about the [ideal] city and its regime' are capable of being more than 'wishful thinking' (Rep.VII.540d; Griffith: 250). Plato does not hold that the existing city is too corrupt to yield genuine philosophers. They exist in contemporary society - 489b-495b, 535c-536c, 539c - but are contemned and rendered useless.

Farmers, doctors, &c. can as necessary provide support for the children in the countryside. Under the surveillance of the philosophers their services will not instil or re-introduce parents' false and corrupt values.

Reading

James Adam, The Republic of Plato, 2nd ed., ed. D.A. Rees, Cambridge: Cambridge University Press, 1965, II: 155, note 30. Answering:

B. Jowett & L. Campbell, Plato's Republic. The Greek Text, edited with notes and essays by the late B. Jowett, M.A., and Lewis Campbell, M.A., LL.D. Oxford: Oxford University Press, 1894.

Plato, The Republic, tr. T. Griffith, Cambridge: Cambridge University Press.