Politics and Markets

The world is not so governed from above that private and social interest always coincide. It is not so managed here below that in practice they coincide. It is not a correct deduction from the principles of economics that self-interest always operates in the public interest. Nor is it true that self-interest generally is enlightened; more often individuals acting separately to attain their own ends are too ignorant or too weak to attain these. Experience does not show that individuals, when they make up a social unit, are always less clear sighted than when they act separately.

The Collected Writings, Vol. IX, 1971-1989

John Maynard Keynes