If this view of the problem of justification is to succeed, we must, of course, describe in some detail the nature of this choice problem. A problem of ration decision has a definite answer only if we know the beliefs and interests of the parties their relations with respect to one another, the alternatives between which they are to choose, the procedure whereby they make up their minds, and so on. As the circumstances are presented in different ways, correspondingly different principles are accepted. The concept of the original position, as I shall refer to it, is that of the most philosophically favoured interpretation of this initial choice