"On Inequality" is one of the very worst pieces of serious analytic philosophy I have ever read. The best part of Franfurt's intellectual tradition -- analytic philosophy -- is taking ideas seriously, and so to honor his life I'll try to make a brief but serious critique of "On Inequality".

This book essentially concatenates two essays, "Economic Equality as a Moral Ideal", and "Equality and Respect". In the first essay, Frankfurt argues that economic equality is less important than the worst-off having enough. As a result, political appeals to the importance of equality are bad philosophy. In "Equality and Respect", he generalises this to a general attack on the concept of egalitarianism.

The basic problem with his work is that the social world is so incredibly abstracted that the truth value of his claims is simply irrelevant -- they have no insight to offer about our actual world. In his essay, he considers different distributions of resources, but gives no serious thought to the actual mechanics of how resources are distributed.

This is fatal to his argument because resource actual distributions are endogenous, rather than exogenous, and so they can't be compared in a vacuum -- to say something meaningful, you genuinely have to take seriously the fact that control of resources is a form of power, and that the powerful tend to use their power to reinforce and maintain their status. So politics and policy -- things he explicitly denies having anything to say about -- are fundamental to understanding the issues involved.

Even making the tiniest possible effort towards taking these issues seriously blows up his argument. For example, suppose that we have people living in a perfectly competitive market. This is about the smallest possible step towards social realism that you can possibly take!

But even here, Negishi's theorem tells us that at a Walrasian equilibrium, the implicit social welfare function maximises the sums of each person's utility, scaled by the inverse of each person's marginal utility of wealth. Now, suppose our people have a utility function which is logarithmic in their wealth -- U(w) = log(w). Then their marginal utility U'(w) = 1/w, and the inverse of that is w. That is, ideal markets value individuals linearly in proportion to their wealth. So the utility function of the ideal market says that saving Jeff Bezos's life is worth the lives of 1.2 million Americans of median wealth, 8 million Poles, or 36 million Indians.

It makes one think that Frankfurt must have used "On Bullshit" as an instruction manual when writing "On Inequality".