The Economics of Welfare
By Arthur C. Pigou
WHEN a man sets out upon any course of inquiry, the object of his search may be either light or fruit—either knowledge for its own sake or knowledge for the sake of good things to which it leads. In various fields of study these two ideals play parts of varying importance. In the appeal made to our interest by nearly all the great modern sciences some stress is laid both upon the light-bearing and upon the fruit-bearing quality, but the proportions of the blend are different in different sciences. At one end of the scale stands the most general science of all, metaphysics, the science of reality. Of the student of that science it is, indeed, true that “he yet may bring some worthy thing for waiting souls to see”; but it must be light alone, it can hardly be fruit that he brings. Most nearly akin to the metaphysician is the student of the ultimate problems of physics. The corpuscular theory of matter is, hitherto, a bearer of light alone. Here, however, the other aspect is present in promise; for speculations about the structure of the atom may lead one day to the discovery of practical means for dissociating matter and for rendering available to human use the overwhelming resources of intra-atomic energy. In the science of biology the fruit-bearing aspect is more prominent. Recent studies upon heredity have, indeed, the highest theoretical interest; but no one can reflect upon that without at the same time reflecting upon the striking practical results to which they have already led in the culture of wheat, and upon the far-reaching, if hesitating, promise that they are beginning to offer for the better culture of mankind. In the sciences whose subject-matter is man as an individual there is the same variation of blending as in the natural sciences proper. In psychology the theoretic interest is dominant—particularly on that side of it which gives data to metaphysics; but psychology is also valued in some measure as a basis for the practical art of education. In human physiology, on the other hand, the theoretic interest, though present, is subordinate, and the science has long been valued mainly as a basis for the art of medicine. Last of all we come to those sciences that deal, not with individual men, but with groups of men; that body of infant sciences which some writers call sociology. Light on the laws that lie behind development in history, even light upon particular facts, has, in the opinion of many, high value for its own sake. But there will, I think, be general agreement that in the sciences of human society, be their appeal as bearers of light never so high, it is the promise of fruit and not of light that chiefly merits our regard. There is a celebrated, if somewhat too strenuous, passage in Macaulay’s Essay on History: “No past event has any intrinsic importance. The knowledge of it is valuable, only as it leads us to form just calculations with regard to the future. A history which does not serve this purpose, though it may be filled with battles, treaties and commotions, is as useless as the series of turnpike tickets collected by Sir Matthew Mite.” That paradox is partly true. If it were not for the hope that a scientific study of men’s social actions may lead, not necessarily directly or immediately, but at some time and in some way, to practical results in social improvement, not a few students of these actions would regard the time devoted to their study as time misspent. That is true of all social sciences, but especially true of economics. For economics “is a study of mankind in the ordinary business of life”; and it is not in the ordinary business of life that mankind is most interesting or inspiring. One who desired knowledge of man apart from the fruits of knowledge would seek it in the history of religious enthusiasm, of martyrdom, or of love; he would not seek it in the market-place. When we elect to watch the play of human motives that are ordinary—that are sometimes mean and dismal and ignoble—our impulse is not the philosopher’s impulse, knowledge for the sake of knowledge, but rather the physiologist’s, knowledge for the healing that knowledge may help to bring. Wonder, Carlyle declared, is the beginning of philosophy. It is not wonder, but rather the social enthusiasm which revolts from the sordidness of mean streets and the joylessness of withered lives, that is the beginning of economic science. Here, if in no other field, Comte’s great phrase holds good: “It is for the heart to suggest our problems; it is for the intellect to solve them…. The only position for which the intellect is primarily adapted is to be the servant of the social sympathies.”… [From the text]
First Pub. Date
1920
Publisher
London: Macmillan and Co.
Pub. Date
1932
Comments
4th edition.
Copyright
The text of this edition is copyright © 1932. This book is available through Transaction Publishers, Inc. Direct all requests for permissions and copyrights to Transaction Publishers, Inc.
- Preface to the Third Edition
- Note to the Fourth Edition
- Part I, Chapter 1
- Part I, Chapter 2
- Part I, Chapter 3
- Part I, Chapter 4
- Part I, Chapter 5
- Part I, Chapter 6
- Part I, Chapter 7
- Part I, Chapter 8
- Part I, Chapter 9
- Part I, Chapter 10
- Part I, Chapter 11
- Part II, Chapter 1
- Part II, Chapter 2
- Part II, Chapter 3
- Part II, Chapter 4
- Part II, Chapter 5
- Part II, Chapter 6
- Part II, Chapter 7
- Part II, Chapter 8
- Part II, Chapter 9
- Part II, Chapter 10
- Part II, Chapter 11
- Part II, Chapter 12
- Part II, Chapter 13
- Part II, Chapter 14
- Part II, Chapter 15
- Part II, Chapter 16
- Part II, Chapter 17
- Part II, Chapter 18
- Part II, Chapter 19
- Part II, Chapter 20
- Part II, Chapter 21
- Part II, Chapter 22
- Part III, Chapter 1
- Part III, Chapter 2
- Part III, Chapter 3
- Part III, Chapter 4
- Part III, Chapter 5
- Part III, Chapter 6
- Part III, Chapter 7
- Part III, Chapter 8
- Part III, Chapter 9
- Part III, Chapter 10
- Part III, Chapter 11
- Part III, Chapter 12
- Part III, Chapter 13
- Part III, Chapter 14
- Part III, Chapter 15
- Part III, Chapter 16
- Part III, Chapter 17
- Part III, Chapter 18
- Part III, Chapter 19
- Part III, Chapter 20
- Part IV, Chapter 1
- Part IV, Chapter 2
- Part IV, Chapter 3
- Part IV, Chapter 4
- Part IV, Chapter 5
- Part IV, Chapter 6
- Part IV, Chapter 7
- Part IV, Chapter 8
- Part IV, Chapter 9
- Part IV, Chapter 10
- Part IV, Chapter 11
- Part IV, Chapter 12
- Part IV, Chapter 13
- Appendix I
- Appendix II
- Appendix III
Part II, Chapter IV
RATES OF RETURN AND THE VALUES OF MARGINAL PRIVATE NET PRODUCTS
§ 1. THE rate of return per unit in money obtained from any quantity of any kind of productive resource in any use is, in general, equal to the value of the marginal private net product of that quantity of that kind of resource there. As between different occupations and places, therefore, the relation between rates of return is the same as the relation between values of marginal private net products; so that equality or inequality among rates of return is the same thing as equality or inequality among values of marginal private net products. In this and the four following chapters I shall, for convenience, sometimes use the term of rate of returns—or, more loosely, returns—in place of the longer synonym.
§ 2. Anybody who has control of any quantity of any form of productive resource will try so to distribute it among various uses that it brings him the largest possible money receipts. If he thinks that, apart from cost of carriage and so on, he can get more money by transferring a unit from any one use to any other, he will do so. It follows that the free play of self-interest, so far as it is not hampered by ignorance, tends, in the absence of costs of movement, so to distribute resources among different uses and places as to render rates of return everywhere equal. By an easy extension of the argument it can be shown that, where there
are costs of movement, the free play of self-interest, again so far as it is not hampered by ignorance, tends, not to bring about equality in rates of return, but to prevent any divergences from equality in excess of those that, relatively to the fact that there
are costs of movement, allow the sum total of returns to attain a maximum.
§ 3. It follows that, if private and social net products everywhere coincide, the free play of self-interest, so far as it is not hampered by ignorance, will tend to bring about such a distribution of resources among different uses and places as will raise the national dividend and, with it, the sum of economic welfare to
a maximum.
*18 The distinctions drawn in the last sections of the preceding chapter show, indeed, that several maxima are possible, so that the one which self-interest tends to bring about need not be the highest maximum attainable. This, however, is a secondary matter. The essential point for our present purpose is that, when marginal private net products and marginal social net products coincide, any obstacles that obstruct the free play of self-interest will, in general, damage the national dividend. In real life, of course, marginal private and marginal social net products frequently do not coincide. In Chapters V.-VIII. this fact will be left out of account: but in later chapters, particularly Chapters IX.-XI., the consequences that follow from it will be fully examined.
post, Chapters XIV.-XVII.
Part II, Chapter V