It might seem fair to make everyone pay the same percentage of their income in taxes. That way, the rich pay more money than the poor do, but everyone keeps the same fraction of their money to use however they wish. Then why does the government make you pay a higher percentage the more money you make? Don’t the rich contribute enough as it is?

In the U.S., we have what’s called a progressive income tax, which means you get taxed at a higher rate the more money you have available for taxation. The reason we have a progressive income tax, even though a proportional tax (where everyone gets taxed at the same percentage) might seem fairer, is because a progressive tax reduces the tax incidence of people with lower ability-to-pay.

What does this mean? Tax incidence “falls” on the group that ends up bearing the brunt of taxation. Usually, tax incidence falls on those with less money (the amount they have to pay in taxes more drastically affects their standard of living). You could take away half of Bill Gates’ or Warren Buffet’s money, and they’d still be amazingly rich, but if you took away half the income of the average worker, his ability to live comfortably – even just to pay all his bills – would be seriously affected. Our economy has made some people incredibly well-off, so we ask them to give more back because they can more easily afford to part with it.