The Economist's blog asks egalitarians to point to some "tangible harm" from income inequality.
In some senses, the question is silly. To see why, imagine a slave society in which the slaves are reasonably content. It would be hard to point to a tangible harm, but something would be wrong.
This just shows that the "tangible harm" criterion is psychologically, economically and philosophically naive. Psychologically so, beecause people adapt to their circumstances, so "losers" don't feel too bad. Economically, because a gain foregone should count as much as a tangible cost; in a slave society no-one can see that freedom creates prosperity better than slavery, but this fact should surely count in our judgment. And philosophically, because inequality matters for more than consequentialist reasons. Justice matters too.
Anyhow, let's address the question. Aside from the ill-health which the Economist mentions - as if death were not tangible enough - I'd cite five other possible harms:
1. Crime. Basic economics says the relatively poor commit more crime than the relatively rich. This is because their opportunities to make money honestly are more limited, and the cost of being imprisonment - foregone earnings - is lower. Empirical work corroborates this. Is it really a coincidence that unequal countries (south America) have more crime than egalitarian ones (Japan, Korea, Scandinavia).
2. Lower social mobility. Societies with higher income inequality have lower social mobility. Politics in the US and the national media in the UK are now largely hereditary occupations. Many of you might think this unhealthy.
3. Slower growth. There are some reasons to think inequality can retard growth, say, by reducing social capital and therefore investment, or by creating credit constraints that prevent potential entrepreneurs.
4. Bad customer service and job dissatisfaction. The inequalities that matter are not merely of income, but of power. Some people have it, some don't. And in companies, these inequalities breed slovenliness and inefficiency. Cloke and Goldsmith put it thus:
Through years of experience, employees learn that it is safer to suppress their innate capacity to solve problems and wait instead for commands from above. They lose their initiative and ability to see how things can be improved. They learn not to care and to accept things as they are. They justify making mistakes and are allowed to be irresponsible and pass the blame to others for their mistakes. They become mindlessly obedient, fatalistic, intransigent and hostile.
5. Inner-city blight. Another consequence of inequalities in power is that poor areas become bad areas, with urban decay, poor schools and crime, because the poor lack the power to get the state to provide proper policing and schools.
So, there are almost certainly tangible harms from inequality. The more awkward question for egalitarians is: would there be more harm done by reducing inequality?