"Investment of capital, to yield its fruit in the future, must be based on expectations, of opportunities in the future. When I put this to Hayek, he told me that this was indeed the direction in which he had been thinking. Hayek gave me a copy of a paper on 'intertemporal equilibrium', which he had written some years before his arrival in London; the conditions for a perfect foresight equilibrium were there set out in a very sophisticated manner."