the formulation of doctrines. There were controversies respecting the nature and influences of money, over the derivation of wages, over the principles of laissez faire (letting things take their own course) over the Malthusian doctrine, and so forth. Amid all this there was one great basic law universally recognized, namely the law of supply and demand, which ranks with the law of gravitation and the law of the conservation of energy among the great fundamental laws of nature. The law of supply and demand is the one thing in economics upon which we may fix our eyes as upon the lode star.
In the course of time we have fallen out of agreement with Walker’s doctrine that political economy has to do with no other subject than wealth. Although it is indeed the science of the production and distribution of wealth we can see that many things pertain to that subject and that economics links hands closely with engineering, biology, and psychology. It is probably the recognition of this that caused the study and exposition of economics to acquire such a strong sociological note 20 or 30 years ago and produced an immense volume of literature that is even more conjectural and controversial than the classicism of the middle of the 19th century.
During the last decade economics took another turn, this time in the direction of quantitative studies. The economist then began to grasp hands with the statistician. The economist began to be a statistician and the statistician began to be an economist. The war gave a great impetus to this. We learned then acutely and fully the need for quantitative information, we acquired increased facilities for getting it and we became accustomed to think internationally and in
