It is almost as hard to define mathematics as it is to define economics, and one is tempted to fall back on the famous old definition attributed to ,… - Kenneth E. Boulding

Adam Smith, who has strong claim to being both the Adam and the Smith of systematic economics, was a professor of moral philosophy and it was at that forge that economics was made. Even when I was a student, economics was still part of the moral sciences tripos at Cambridge University. It can claim to be a moral science, therefore, from its origin, if for no other reason. Nevertheless, for many economists the very term “moral science” will seem like a contradiction. We are strongly imbued today with the view that science should be wertfrei and we believe that science has achieved its triumph precisely because it has escaped the swaddling clothes of moral judgment and has only been able to take off into the vast universe of the “is” by escaping from the treacherous launching pad of the “ought.” Even economics, we learn in the history of thought, only became a science by escaping from the casuistry and moralizing of medieval thought.

We should always bear in mind that numbers represent a simplification of reality.

One advantage of exhibiting a hierarchy of systems in this way is that it gives us some idea of the present gaps in both theoretical and empirical knowledge. Adequate theoretical models extend up to about the fourth level, and not much beyond. Empirical knowledge is deficient at practically all levels.