In essence, the theory of comparative advantage says that it pays countries to trade because they are different.

ECONOMIST: A short tour of economic theory

Malkiel was in essence embracing the efficient markets theory that says fund managers as a group cannot outperform the market, so investors who pay big commissions and other management expenses are cheating themselves.

FORBES: About Burton Malkiel

The computational theory of mind, in essence, says that your brain works like a computer.

FORBES: Why Your Brain Isn't A Computer