Economics as “moral science”
In the introduction of his Treatise on Human Nature (1739 [1978]: xv f.) Hume states:
'Tis evident, that all the sciences have a relation, greater or less, to human nature; and that however wide any of them may seem to run from it, they still return back by one passage or another....
Here then is the only expedient, from which we can hope for success in our philosophical researches, to leave the tedious lingering method, which we have hitherto followed, and instead of taking now and then a castle or village on the frontier, to march up directly to the capital or center of these sciences, to human nature itself; which being once masters of, we may every where else hope for an easy victory. From this station we may extend our conquests over all those sciences, which more intimately concern human life, and may afterwards proceed at leisure to discover more fully those, which are the objects of pure curiosity. There is no question of importance, whose decision is not compriz'd in the science of man; and there is none, which can be decided with any certainty, before we become acquainted with that science. In pretending, therefore, to explain the principles of human nature, we in effect propose a compleat system of the sciences, built on a foundation almost entirely new, and the only one upon which they can stand with any security.
This passage exhibits certain similarities with Kant's Copernican turn towards the knowing subject. However, the “moral science” Hume envisions is devoid of Kant's claims to a priori knowledge. Its epistemology is broadly speaking a sub-discipline of the psychology of knowledge. Likewise Hume translates the “logic of inter-active choice making” into a specific type of social-institutional psychology. Yet, much of what economists actually do is a far cry of the fact finding and hypothesis-testing mission of empirical science. Practical concerns of making the world a better place seem to play a much greater role in economics than in natural sciences. Beyond experiments (field and laboratory), econometric studies (including their focus on identifying causal factors), the new economic history and so on, economics addresses basic normative concerns as in welfare economics.