Mark J. Perry quotes Milton Friedman on the fixed pie fallacy (also known as the fixed quantity of wealth fallacy and the zero-sum fallacy):
“Most economic fallacies derive from the tendency to assume that there is a fixed pie, that one party can gain only at the expense of another.”
Warren Buffett does not become "richer" contingent upon the rest of us becoming poorer, just as the U.S. does not benefit by imposing tariffs on foreign goods. Professor Perry elaborates.
In terms of globalization and international trade, we see the “economic fallacy of the fixed pie” in operation all the time, just listen to Lou Dobbs on CNN every night. Many people think that China or Japan are somehow benefiting at our expense because of trade, or because of a current account deficit with those countries. Many people think that the gains from globalization somehow lift up the standard of living in China or India, by bringing down the standard of living in the USA; or that the gain in wages in other countries comes at the expense of a decline in American workers’ wages, etc.
But all of those beliefs are all based on the fixed pie fallacy. There is NOT a fixed, static amount of wealth or wages in the world, which is what the fixed pie fallacy assumes.
Stand back from economics and trade and think instead about life expectancy or literacy. There is certainly not a fixed amount of “life expectancy” in the world, nor is there a fixed amount of “literacy.” It is certainly possible for the life expectancy or literacy rates in 0ther countries to INCREASE, without DECREASING life expectancy or literacy in the US! That is, advances in life expectancy or literacy in China do NOT come at the expense of the US, because there is NOT a fixed amount, and the most likely outcome is that advances will continue to take place in BOTH countries.
Likewise, since there is not a fixed amount of wealth or prosperity in the world, globalization and trade will benefit BOTH the U.S and China.