The Republic by Plato Part 4 Page 28

the discovery in this way: I mean to begin with the assumption that our State, if rightly ordered, is perfect.

That is most certain.

And being perfect, is therefore wise and valiant and temperate and just.

That is likewise clear.

And whichever of these qualities we find in the State, the one which is not found will be the residue?

Very good.

If there were four things, and we were searching for one of them, wherever it might be, the one sought for might be known to us from the first, and there would be no further trouble; or we might know the other three first, and then the fourth would clearly be the one left.

Very true, he said.