The Theory of Economics does not furnish a body of settled conclusions immediately applicable to policy. It is a method rather than a doctrine, an apparatus of the mind, a technique of thinking, which helps its possessor to draw correct conclusions. It is not difficult in the sense in which mathematical and scientific techniques are difficult; but the fact that its modes of expression are much less precise than these, renders decidedly difficult the task of conveying it correctly to the minds of

§1. Theory and Fact . The controversy between the "Theorist" and the "Practical Man" is common to all branches of human affairs, but it is more than usually prevalent, and perhaps more than usually acrid in the economic sphere. It is always a rather foolish controversy, and I have no intention of entering into it, but its prevalence makes it desirable to emphasize a platitude. Economic theory must be based upon actual fact: indeed, it must be essentially an attempt, like all theory, to describe

§1. Preliminary Statement of Three Laws . The recognition of order in any branch of natural phenomena is but the prelude to the formulation of a set of laws, the simpler as the order is more universal, which describe, and as we say, explain it. Thus the perception of the even, elliptical courses of the heavenly bodies led to the statement of the law of gravitation and the laws of motion. In economics, similar laws have long since been enunciated, and have proved themselves such valuable instrume

§1. The Forces behind Supply and Demand . The laws enunciated in the preceding chapter constitute the framework and skeleton of all economic analysis; but they do not carry us very far. It is only through the agency of these laws that any influence can affect the price of anything: but what influences may so affect it is a question which we have still to consider. Let us begin with ordinary commodities and ask ourselves, in the light of experience and common sense, upon what factors their price

§1. An Illustration from Coal . We have already had occasion to note the symmetry which characterizes the relations of demand and supply to price. This symmetry was apparent throughout the argument of Chapter II, and it was a striking feature of the diagrams which we employed to illustrate the argument. We shall do well to cultivate a lively sense of this symmetry, for it will frequently save us from ignoring factors which have a vital bearing on the problems we are considering. We should never

§1. Marginal Cost under Joint Supply . Several references have been made above to joint products, a relation which it will be convenient now to describe as that of Joint Supply. Our sense of symmetry should make us look for a parallel relation on the side of demand; and it is not far to seek. There is a "joint demand" for carriages and horses, for golf clubs and golf balls, for pens and ink, for the many groups of things which we use together in ordinary life. But the most important instances of

§1. The Special Characteristics of Land . In the great process of co-operation by which the wants of mankind are supplied, Nature is an indispensable participant. She renders her assistance in an infinite variety of ways, of which the properties of the soil which man cultivates form only one; but the sunshine and rain which enable the farmer to grow his crops; the coal and iron ore beneath the surface of the earth, can be regarded for our present purpose as forming part of the land with which th

§1. Profits and Earnings of Management . The profits of a business, as they are ordinarily reckoned, whether for the purposes of income tax or of a balance sheet, comprise several elements which are fundamentally distinct. The relative importance of these various elements varies greatly from one type of business to another. The profits of a private business include, for instance, the remuneration of the work of management, which in the case of a Joint Stock Company is mostly paid for by salaries

§1. A Reference to Marx. . Interest is the price paid simply for the use of capital. But what is capital, and in what does its use consist? What claim has it to be regarded as an independent factor of production? Our very familiarity with the term, our habit of employing it with the rich looseness of every-day life is an obstacle to the clearness of thought, which is again essential. We recognize, most of us, clearly enough that capital, although we reckon it in terms of money, consists, like in

§1. A Retrospect on Laissez-faire. When, a century and a half ago, the foundations were being laid in the Western world of systematic economic theory, the public attention was much occupied with a subject, which indeed has not ceased to hold it: that of the failings of Governments. The general interest in that topic was shared by the pioneers of economic thought, of whom, in Great Britain, Adam Smith was the most notable. It was indeed their practical concern with the concrete economic issues of

§1. Comparative Costs . Beneath the great diversity of the considerations which are applicable to the different agents of production, certain general conclusions emerge from the analysis of the last four chapters. In no case did we find that the aggregate supply of the agent was determined by clear and certain economic laws, possessing any fundamental significance. The supply of natural resources is a fixed thing, quite independent of the efforts or the desires of man. However the supply of capi