Ha! You basically beat me to saying the same thing. Of course Gates likes the two rich people who do things that he finds morally positive (and who resemble him) more than the guy he finds morally neutral. "Tax the rich more, but not me until I'm dead!" That said, I appreciate that he seems to understand Piketty's sentiment, although he's gonna have to do better than pointing to an AEI study to convince me that the world is not as unequal as Piketty, Stiglitz, Krugman, and all the rest say it is. Sure the world is better for poor people now than it was before. That doesn't mean it couldn't be a whole lot better for everyone given a different policy direction. Anyway, what's the difference if we tax wealth? The government can't tax you on what you don't own. A wealth tax might encourage more philanthropy, given that people might want to shed assets faster (although I do see problems of liquidity for some people, e.g. an entrepreneur whose company is worth $100M, but who is cash poor).