I would like to thank you for your expression of incredulity. It forced me to look at the question a little more closely, and led me to this excellent paper by Binmore. If I had read it first, I would not have been so complimentary about Rawls. I had forgotten just how different Rawls's 'Veil of Ignorance' is from Harsanyi's. And it is Harsanyi's version that deserves our respect, not Rawls's. Nevertheless, I think I was technically correct. Rawls is mathematically respectable, however deficient he is on more realistic grounds.

There are several issues here worth discussing, including:

• Rawls's maximin vs Harsanyi's lottery (Rawls, in effect, assumes infinite risk aversion)
• Objective vs subjective interpersonal comparisons. Do people agree on their interpersonal comparisons? Does it matter, since decision-making is subjective in any case?
• Our lack of direct access to other people's preferences (which is also a problem in standard complete-information game theory even if you don't attempt interpersonal comparisons).

I probably ought to put together a top-level posting on this topic - if only to clarify my own thinking. But I'm too lazy right now. So instead, I'll just reread Binmore's paper and maybe check out some of his references.