 The natural sciences are ultimately based on facts, as established by laboratory experiment. Physical and biological theories are confronted with these facts, and are rejected when in conflict with them. The perfection of these theories no less than the improvement of technological and therapeutical procedures requires more and better laboratory research. These experimental ventures absorb time, painstaking effort of specialists, and costly expenditure of material. Research can no longer be conducted by isolated and penniless scientists, however ingenious. The seat of experimentation today is in the huge laboratories supported by governments, universities, endowments and big business. Work in these institutions has developed into professional routine. The majority of those employed in it are technicians recording those facts, which the pioneers, of whom some are themselves experimenters, will one day use as building stones for their theories. As far as the progress of scientific theories is concerned, the achievement of the rank and file researcher are only ancillary, but very often his discoveries have immediate practical results in improving the methods of therapeutics and of business. Ignoring the radical epistemological difference between the natural sciences and the sciences of human action, people believe that what is needed to further economic knowledge is to organise economic research according to the well-tried methods of the Institutes for Medical, Physical and Chemical Research. Considerable sums of money have been spent for what is labelled economic research. In fact, the subject matter of the work of all these institutes is recent economic history. It is certainly a laudable thing to encourage the study of economic history. However instructive the result of such studies may be, one must not confuse them with the study of economics. They do not produce facts in the sense in which this term is applied with regard to the events tested in laboratory experiments. They do not deliver bricks for the construction of aposteriori hypotheses and theorems. On the contrary, they are without meaning if not interpreted in the light of theories developed without reference to them. There is no need to add anything to what has been said in this respect in the preceding chapters. No controversy concerning the causes of a historical event can be solved on the ground of an examination of the facts, which is not guided by definite praxeological theories. The foundation of Institutes for Cancer Research can possibly contribute to the discovery of methods for fighting and preventing this pernicious disease. But a business cycle research institute is of no help in endeavours to avoid the recurrence of depressions. The most exact and reliable assemblage of all the data concerning economic depressions of the past is of little use for our knowledge in this field. Scholars do not disagree with regard to these data. They disagree with regard to the theorems to be resorted to in their interpretation. Still more important is the fact that this is impossible to collect the data concerning a concrete event without reference to the theories held by the historian at the very outset of his work. The historian does not report all facts, but only those which he considers as relevant on the ground of his theories. He omits data considered irrelevant for the interpretation of the events. If he is misled by faulty theories, his report becomes clumsy and maybe almost worthless. Even the most faithful examination of a chapter of economic history, though it be the history of the most recent period of the past, is no substitute for economic thinking. Economics, like logic and mathematics, is a display of abstract reasoning. Economics can never be experimental and empirical. The economist does not need an expensive apparatus for the conduct of his studies. What he needs is the power to think clearly and to discern in the wilderness of events what is essential from what is merely accidental. There is no conflict between economic history and economics. Every branch of knowledge has its own merits and its own rights. Economists have never tried to belittle or deny the significance of economic history. Neither do real historians object to the study of economics. The antagonism was intentionally called into being by the socialists and interventionists who could not refute the objections raised against their doctrines by the economists. The historical school and the institutionalists tried to displace economics and to substitute empirical studies for it precisely because they wanted to silence the economists. Economic history, as they planned it, was a means of destroying the prestige of economics and of propagandising for interventionism.