Excerpt from Proceedings of the Aristotelian Society, Vol. 8 IN an address delivered some two years ago and Since then published, I made an attempt to estimate the influence on economic ideas of the great advances effected in the methods of modern logicians. Whether I succeeded I do not know. But the moral which I sought to point was that economists of more than one shade of opinion would do well to criticise their categories, and to see to it that they do not confuse what are in reality only valuable working conceptions with concrete realities. My purpose in this paper is to pursue the same method, and to suggest that, in yet another region, abstractions are apt to be hypostatised into realities. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.