After a useful discussion of the Visa fee controversy, Tyler Cowen offers an entertaining and instructive addendum:

When issues of this sort arise, there is a common pattern in blogospheric discussion: Blogger A criticizes a market practice with tones of absolute condemnation. Blogger C (in this case, me!) responds with a plausible scenario, and a microeconomics-consistent first-order explanation, that things aren’t so bad after all. Blogger D tries to defend Blogger A by shifting the burden of proof to Blogger C to demonstrate that markets are efficient in such a case and by leveling charges of market fundamentalism and by citing some second or third best arguments that the market can fail after all. Don’t be fooled by that polemic slide in emphasis; the burden of proof is on the critics here — those asserting the existence of an evil and asking us to move beyond a loose agnosticism – not on me.

I imagine this won’t persuade Bloggers A and D.