From Chapter 1 of Law, Legislation, and Liberty, where he frames the problem that fueled the work he produced during the second half of his academic career:
“The discussion of the problems with which we are concerned was long hampered by the universal acceptance of a misleading distinction which was introduced by the ancient Greeks and from whose confusing effect we have not yet wholly freed ourselves. This is the division of phenomena between those which in modern terms are ‘natural’ and those which are ‘artificial’. The original Greek terms, which seem to have been introduced by the Sophists of the fifth century B.C., were physei, which means ‘by nature’ and, in contrast to it, either nom? , best rendered as ‘by convention’, or thesei, which means roughly ‘by deliberate decision’.18 The use of two terms with somewhat different meanings to express the second part of the division indicates the confusion which has beset the discussion ever since. The distinction intended may be either between objects which existed independently and objects which were the results of human action, or between objects which arose independently of, and objects which arose as the result of, human design. The failure to distinguish between these two meanings led to the situation where one author could argue with regard to a given phenomenon that it was artificial because it was the result of human action, while another might describe the same phenomenon as natural because it was evidently not the result of human design. Not until the eighteenth century did thinkers like Bernard Mandeville and David Hume make it clear that there existed a category of phenomena which, depending on which of the two definitions one adhered to, would fall into either the one or the other of the two categories and therefore ought to be assigned to a distinct third class of phenomena, later described by Adam Ferguson as ‘the result of human action but not of human design’. These were the phenomena which required for their explanation a distinct body of theory and which came to provide the object of the theoretical social sciences.”
