They study stylized facts, theorize them and reduce them to logical relationships and to models of how economic systems work, from which they draw indications for the conduct of business and for the action of the public authorities. Towards the end of the nineteenth century the role of credit and banking and, more generally, of finance emerged in all its importance.
The separation, the real and logical distinction, between economic agents who save and those who use savings or make investments by borrowing capital has enormous implications not only for the expansion of economic activity but also for the stability of the growth process, both within individual economies and across economic systems.