Life is not a great lottery with purely random outcomes. We do not daily face a totally chaotic and unpredictable world. Mankind is not just a straw in the wind blown about by cosmic forces. If it was otherwise, if life was just a matter of chance, it would be impossible to make plans for the future. Without a predictable return on the sacrifice of present consumption there would be no saving, no investment, no new techniques of production or organization, no growth. Primitive man would have remained cowering in his caves.