Plato’s arguments for the reality of ideas are but a reiteration (as regards the argument) of Parmenides great argument.

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There is nothing within reason which gives any man a right to more happiness than is the portion of a brother man. The political system of the world — nay, the political systems — rest(s) on a basis entirely and wholly wrong. As long as this continues (it is clear) man will be unhappy. lt will endure with the world.

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All actions, good or bad, have their root in power; the bad by preservation of that power, the good by denial of it. [...]

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Contingent things do cease to be what they are, it is the ideas of them that continue to exist (be).

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What commences, ends. Because what commences is in time and what is in time, ends.

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«Does the totality of things — the universe — in time, end?» Things do.

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Universe as subject contains in itself time and space, so it is neither eternal nor will end, neither infinite nor finite; time and space being not external, as they would have to be to enable us to speak of finiteness and of infinity.