OK, he didn’t actually say that in so many words. But if you follow through on the logic of his excellent speech at Princeton yesterday, that’s where you end up.

Actually, there were several things Bernanke said that were politically controversial. When he declared that

physical beauty is evolution’s way of assuring us that the other person doesn’t have too many intestinal parasites

he was endorsing the theory of evolution — which puts him at odds with a large majority of Republicans, 58 percent of whom believe that man was created in his present form within the last 10,000 years.

But the big thing in Bernanke’s remarks was his discussion of the obligations of the successful, even within a supposedly meritocratic society:

We have been taught that meritocratic institutions and societies are fair. Putting aside the reality that no system, including our own, is really entirely meritocratic, meritocracies may be fairer and more efficient than some alternatives. But fair in an absolute sense? Think about it. A meritocracy is a system in which the people who are the luckiest in their health and genetic endowment; luckiest in terms of family support, encouragement, and, probably, income; luckiest in their educational and career opportunities; and luckiest in so many other ways difficult to enumerate–these are the folks who reap the largest rewards. The only way for even a putative meritocracy to hope to pass ethical muster, to be considered fair, is if those who are the luckiest in all of those respects also have the greatest responsibility to work hard, to contribute to the betterment of the world, and to share their luck with others.

OK, this is, whether BB realizes it or not (he probably does) basically a Rawlsian view of the world, in which you think of life as a kind of lottery in which you draw a ticket that includes things like your genetic endowment as well as the wealth of your parents. And what you’re supposed to do, ethically, is support the economic and social system you would choose if you had to enter that lottery not knowing what ticket you were going to draw — if you were making political choices behind the “veil of ignorance”.

As soon as you portray the choice that way, you’ve introduced a strong presumption in favor of redistribution. After all, if you should happen to end up as a member of the top 1 percent, an extra dollar at the margin won’t mean a lot to you; but if you should happen to end up as a member of, say, the bottom quintile, an extra dollar could make a lot of difference. So you should, other things equal, favor a system of progressive taxation and generous aid to the poor and unlucky.

So why not favor complete leveling, America as Cuba? Because for many reasons, both economic and political, we favor a market economy in which people make decentralized decisions about working, saving, and so on. And this means that incentive effects become important; you can’t levy 100 percent taxation on the rich, or completely insulate the poor from any consequences of low income, without destroying the incentives you need to make the economy work.

The question then becomes one of numbers. In particular, how high should we set the top tax rate? From a Rawlsian perspective, the key thing about very high incomes is that making them a bit higher or lower basically doesn’t matter — if you are lucky enough to find yourself in the top 0.1 percent (say), the marginal value of a dollar to your welfare is trivial compared with the value of that dollar to almost anyone else. So the top tax rate should be set solely with regard to the amount of money it raises for other purposes; essentially, you should soak the rich up to the point where any further rise in the tax rate would actually reduce revenue.

And we have a pretty good idea, based on careful statistical studies, of where that optimal top rate lies; 73 percent, say Diamond and Saez, maybe 80 percent, say Romer and Romer.

Does this sound wildly radical to you? Well, it’s just where the logic and evidence take you once you adopt a more or less Rawlsian view of social justice — which is exactly what Ben Bernanke did at Princeton.

Some people have suggested that BB’s speech had a touch of radicalism to it. Little did they know!