"Great difficulties are met with in stating a clear and straightforward exposition of price theory because of the fact that the given conditions or data of the problem are so different according to the length of the time period which the explanation takes into account. The forces which immediately regulate prices are different from those which ultimately control, and there are degrees or stages in both immediateness and ultimateness."...

Frank Hyneman Knight (1885-1972) was an important economist of the twentieth century. He obtained a B. S. and an M. A. (the latter in German) in 1913 at the University of Tennessee. He then moved to Cornell University for doctoral studies. His initial main subject was philosophy, but he soon switched to economics. He studied with Alvin Johnson and Allyn Young, who both supervised the work on his dissertation that was completed in 1916 under the title Cost, Value and Profit. He would subsequently revise it for publication under its more familiar name Risk, Uncertainty and Profit (1921). The famously opinionated Knight used his numerous book reviews in Chicago's Journal of Political Economy as a vehicle for his thoughts on many subjects. As a result, he was embroiled in many debates with the most prominent economists of his day ranging over capital theory, welfare theory, Keynesian theory and positivist methodology. His other works include: Cost of Production and Price Over Long and Short Periods (1921) and The Ethics of Competition (1923).

"Great difficulties are met with in stating a clear and straightforward exposition of price theory because of the fact that the given conditions or data of the problem are so different according to the length of the time period which the explanation takes into account. The forces which immediately regulate prices are different from those which ultimately control, and there are degrees or stages in both immediateness and ultimateness. The average student of economics is likely to be quite baffled by these distinctions and to get no clear ideas at all; but he is still more baffled by differences in degree, where distinctions are not sharply drawn and statements are left in the form of "it depends." This paper looks to the problem of exposition from the standpoint of the student rather than to the correction of errors in accepted doctrine, but the course of the argument will have to note cases in which current phraseology is misleading to unwary readers if it does not represent fundamental misconceptions on the part of economists themselves...."