My real point is that neither maximizing revenue nor “fairness” are the sole criteria by which a tax policy is judged.

The purpose of taxes is to give us the best society. That’s a complicated thing to measure, but that’s the real goal. If, as a whole, we’re better off with a less than “fair” tax policy, that policy is still a better one.

It’s effectively impossible to build a tax system that’s “fair” and also gets the job done. First, it’s impossible to settle on a definition of “fair”. One (overly simplistic) notion of “fair” would have every citizen pay the same dollar amount. Or the same percentage of income. You yourself have pointed out that those are not “really” fair policies because of their disproportionate burden on the poor.

Our current compromise is use a graduated tax — it’s “fair” in some more sophisticated sense, because it’s putting most of the tax burden on discretionary income, rather than on the income used for basic necessities. As I’ve argued, too, it’s also “fair” in the sense that the wealthy reap the benefits of good government in larger proportion than the poor.

The key point, though, is that we’ve abandoned a strict notion of fairness because that’s not the real goal. We need the tax revenue to properly govern, but we want the collection of it to have the least negative impact on society, so we’ve structured it so those able to bear the burden are the ones who shoulder it.

Sam Harris recently blogged about Buffett’s op-ed. In a followup post, he made the following observation:

Would Steve Ballmer, CEO of Microsoft, rather have $10 billion in a country where the maximum number of people are prepared to do creative work? Or would he rather have $20 billion in a country with the wealth inequality of an African dictatorship and commensurate levels of crime? I’d wager he would pick door number #1. But if he wouldn’t, I maintain that it is only rational and decent for Uncle Sam to pick it for him.

Well said, Sam.