[Central banks might have to intervene to counter "perverse" or "grossly excessive" speculation.] By such means, the monetary authorities can attempt to make the market for foreign exchange approximate toward what it would have been if there had been free competitive speculation with correct foresight of future movements. In this case all that the authorities have to do is to anticipate more correctly than private speculators the future course of exchange rates. And in so far as they do so they will make a profit at the expense of the private speculator.

James Meade (1951), The theory of international economic policy, Vol. 1, p. 224; as cited in: Peter B. Kenen (1994), Exchange Rates and the Monetary System, p. 74