Carlo De Cugis, in using Keynes' analogy of economists as dentists referred to by Professor Kindleberger, identified four categories of ‘dentists’: (i) economists, who were supposed to treat Homo oeconomicus, but were often more interested in testing their own instruments, sometimes at the expense of their patients; (ii) economic historians, who attended to groups of historical men who, being dead, were unable to give an account of their symptoms; (iii) political economists who were interested in treatment for its own sake; and finally, (iv) historians of economic thought, who were the dentists' dentists because they treated the previous three categories.

Addressing the issue of tools, Professor De Cugis argued that economic historians, as well as using laws originally developed by economists, were beginning to formulate their own laws. In reference to the use of the economists' laws by economic historians, Professor De Cugis cited the English industrial revolution as an example of a unique event in economic history which, as such, could not be generalized by resorting to some economic law. Although the English industrial revolution was a complex phenomenon made up by various components (e.g. the increase in GNP and investment) which were amenable to being generalised by means of appropriate economic laws, yet the phenomenon itself consisted of a unique combination of interrelated processes. This called for an overall assessment aimed at answering questions such as whether or not the English industrial revolution had been a case of balanced growth.

Professor De Cugis, in alluding to the formulation of laws by economic historians, acknowledged that economic laws were relevant when historical events, however complex, were not unique.