That's certainly fair in some senses, but if you consider money per household to be of decreasing marginal utility (your first 10k of income is a much larger ju

That's certainly fair in some senses, but if you consider money per household to be of decreasing marginal utility (your first 10k of income is a much larger jump in quality of life than your 15th 10k) then a tax that is fair based on utility rather than percentage or dollar amount is progressive.