This is terribly important as I think it clarifies my main problem with the issue (and which prompted my comment.)
The success of teaching Comparative Advantage rests on a beautifully simple model, a little bit of game theory, nothing more. From that (if you read the mises link I put in my other comment) they are happy to build a whole assertion of "good things."
The problem with free mobility of capital is that it doesn't disrupt the generic assumption that free trade makes for a larger "total sum of wealth" but that it has the potential to massively destabilize the utilisation of that wealth, leaving whole countries effectively unemployed.
This doesn't bother the rich, but it should bother the rest of us.
Seeing the power of a simple model, badly applied in all these economics classes and textbooks, I wondered, what if we can build a simple little model that demonstrates (or not) my fears about what the movement of capital means for the stability of the system. It could be a powerful tool for helping people think carefully about trade.
In this way we might raise the well being of all individuals despite differences in relative productivities. In this description, we do not predict that a result will carry over to the complex real world. Instead we carry the logic of comparative advantage to the real world and ask how things would have to look to achieve a certain result (maximum output and benefits). In the end we should not say that the model of comparative advantage tells us anything about what will happen when two countries begin to trade, instead we should say that the theory tells us some things that can happen.
Comparative advantage is important as a rebuttal to naive zero-sum thinking, not as a predictor of performance in a free-trade scenario which does not conform to the assumptions.
