Economics: Complex Windows

“In some ways, the effect of achieving understanding is to reverse completely our initial attitude of mind. For everyone starts (as we have said) by being perplexed by some fact or other: for instance... the fact that the diagonal of a square is incommensurable with the side. Anyone who has not yet seen why the side and the diagonal have no common unit regards this as quite extra- dinary. But one ends up in the opposite frame of mind... for nothing would so much—abbergast a mathematician as...