[sjy]

Generally Piketty is dealing with inequality produced by differences in income from capital, not labour. His reason for focusing on capital income is explained in depth, especially in chapter 7. In short, the distribution of capital ownership is always more concentrated than the distribution of income from labor, so we should be worrying about wealth inequality and inheritance. This is why Piketty proposes a wealth tax, not an income tax of the kind that pg says will 'be fighting a losing battle against increasing variation in productivity.'