Good & Bad Inequality

Greg Mankiw points out that to the extent tax cuts for high income earners increase their work efforts and/or reduce tax evasion, this will lead to increased inequality not just in after tax terms but also in pre-tax terms.

To the extent this is true, increased inequality is nothing that the non-rich should be unhappy about. This is to the contrary good for the non-rich.

There are other sources of inequality that are bad, but to the extent it is the effect of increased productive activities by the rich caused by for example tax cuts, it is good not just for the rich, but for others as well.