That the sum of mutual trades nets down to zero is not particularly challenging either.

And if anyone has failed to think through even something as simple as that, it would be wise to simply avoid commenting -something that PHD students should be sensitive to. You'll be surprised how often I fail to give a definitive advice about insects taxonomy. Or even about microbiology, or statistical physics, fields in which I actually hold a degree.

This is not to say that your friends are not nice people. But I remain baffled by how easily macroeconomics get treated like a religion -even by economists.

Earth provides enough to satisfy every man's need, but not every man's greed. Gandhi