Chapter 39 XXXIX Section 3: Economic Cognition and Human Action
Man’s freedom to choose and to act is restricted in a threefold way. There are first the physical laws to whose unfeeling absoluteness man must adjust his conduct if he wants to live. There are second the individual’s innate constitutional characteristics and dispositions and the operation of environmental factors; we know that they influence both the choice of the ends and that of the means, although our cognizance of the mode of their operation is rather vague. There is finally the regularity of phenomena with regard to the interconnectedness of means and ends, viz., the praxeological law as distinct from the physical and from the physiological law.
The elucidation and the categorial and formal examination of this third class of laws of the universe is the subject matter of praxeology and its hitherto best-developed branch, economics. The body of economic knowledge is an essential element in the structure of human civilization; it is the foundation upon which modern industrialism and all the moral, intellectual, technological, and therapeutical achievements of the last centuries have been built. It rests with men whether they will make the proper use of the rich treasure with which this knowledge provides them or whether they will leave it unused. But if they fail to take the best advantage of it and disregard its teachings and warnings, they will not annul economics; they will stampout society and the human race.
Also: Human Action – Mises.org