Not only is it possible to devise complete models of the economy on hypotheses other than rationality, but in fact virtually every practical theory o… - Kenneth Arrow

Among economic phenomena which have in some way been tied up with the existence of uncertainty, three classes may be distinguished: (1) those which by their very definition are concerned with uncertainty; (2) those which are not related to uncertainty by definition but nevertheless have no other conceivable explanation; (3) those whose relation to uncertainty is more remote and disputable.

Government economic policy, like almost any realistic decision problem, has two fundamental characteristics: it is sequential and it is uncertain.

In addition to ignoring game aspects of the problem of social choice, we will also assume in the present study that individual values are taken as data and are not capable of being altered by the nature of the decision process itself. This, of course, is the standard view in economic theory (though the unreality of this assumption has been asserted by such writers as Veblen, Professor J. M. Clark, and Knight) and also in the classical liberal creed. If individual values can themselves be affected by the method of social choice, it becomes much more difficult to learn what is meant by one method’s being preferable to another.