Walter Williams, a renowned economist at George Mason University, answers this question.

Many people believe that free market capitalism is selfish, even immoral. They say it's about greed, about a hunger for money and power; that it helps the rich and hurts the poor. They're wrong. The free market is not only economically superior, it is morally superior to any other way of organizing economic behavior. Here's why.

The free market calls for voluntary actions between individuals. There's no coercion. In a free market, if I want something from you, I have to do something for you. Let's say I mow your lawn and you pay me twenty dollars. What does that twenty dollars really mean? When I go to the grocer and say, "I would like to have four pounds of steak" He, in effect, says to me, "You want a lot of people to serve you -- ranchers, truckers, butchers, and packagers. All these people have to be paid. What did you do to serve your fellow man?"

"Well," I say, "I mowed my fellow man's lawn." And the grocer says, "Prove it." Then I offer him the twenty dollars. Think of the money that you've earned as a certificate of performance. It's proof that you've served your fellow man.

Read more: Is Capitalism Moral?