Living in a society, instead of on a desert island, does not relieve a man of the responsibility of supporting his own life. The only difference is that he supports his life by trading his products or services for the products or services of others. And, in this process of trade, a rational man does not seek or desire any more or any less than his own effort can earn. What determines his earnings? The free market, that is: the voluntary choice and judgment of the men who are willing to trade him their effort in return.

- Ayn Rand. The virtue of selfishness (1964).