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It follows that in a given situation of technique, resources and factor cost per unit of employment, the amount of employment, both in each individual firm and industry and in the aggregate, depends on the amount of the proceeds which the entrepreneurs expect to receive from the corresponding output.[4]


For entrepreneurs will endeavour to fix the amount of employment at the level which they expect to maximise the excess of the proceeds over the factor cost.



4.An entrepreneur, who has to reach a practical decision as to his scale of production, does not, of course, entertain a single undoubting expectation of what the sale-proceeds of a given output will be, but several hypothetical expectations held with varying degrees of probability and definiteness.


By his expectation of proceeds I mean, therefore, that expectation of proceeds which, if it were held with certainty, would lead to the same behaviour as does the bundle of vague and more various possibilities which actually makes up his state of expectation when he reaches his decision.


可能性→期待状態 = 収益の期待→決定

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Chapter 3.The Principle of Effective Demand

第3章 効果的需要の原理

WE need, to start with, a few terms which will be defined precisely later.


In a given state of technique, resources and costs, the employment of a given volume of labour by an entrepreneur involves him in two kinds of expense:


first of all, the amounts which he pays out to the factors of production (exclusive of other entrepreneurs) for their current services, which we shall call the factor cost of the employment in question;


and secondly, the amounts which he pays out to other entrepreneurs for what he has to purchase from them together with the sacrifice which he incurs by employing the equipment instead of leaving it idle, which we shall call the user cost of the employment in question.[1]



The excess of the value of the resulting output over the sum of its factor cost and its user cost is the profit or, it we shall call it, the income of the entrepreneur.



The factor cost is, of course, the same thing, looked at from the point of view of the entrepreneur, as what the factors of production regard as their income.



Thus the factor cost and the entrepreneur’s profit make up, between them, what we shall define as the total income resulting from the employment given by the entrepreneur.



The entrepreneur’s profit thus defined is, as it should be, the quantity which he endeavours to maximise when he is deciding what amount, of employment to offer.


It is sometimes convenient, when we are looking at it from the entrepreneur’s standpoint, to call the aggregate income (i.e. factor cost plus profit) resulting from a given amount of employment the proceeds of that employment.


On the other hand, the aggregate supply price[2] of the output of a given amount of employment is the expectation of proceeds which will just make it worth the while of the entrepreneurs to give that employment.[3]



1. A precise definition of user cost will be given in Chapter 6.


2. Not to be confused (vide infra) with the supply price of a unit of output in the ordinary sense of this term.


3. The reader will observe that I am deducting the user cost both from the proceeds and from the aggregate supply price of a given volume of output, so that both these terms are to be interpreted net of user cost;


whereas the aggregate sums paid by the purchasers are, of course, gross of user cost. The reasons why this is convenient will be given in Chapter 6. The essential point is that the aggregate proceeds and aggregate supply price net of user cost can be defined uniquely and unambiguously; whereas, since user cost is obviously dependent both on the degree of integration of industry and on the extent to which entrepreneurs buy from one another, there can be no definition of the aggregate sums paid by purchasers, inclusive of user cost, which is independent of these factors. There is a similar difficulty even in defining supply price in the ordinary sense for an individual producer; and in the case of the aggregate supply price of output as a whole serious difficulties of duplication are involved, which have not always been faced. If the term is to be interpreted gross of user cost, they can only be overcome by making special assumptions relating to the integration of entrepreneurs in groups according as they produce consumption-goods or capital-goods which are obscure and complicated in themselves and do not correspond to the facts. If, however, aggregate supply price is defined as above net of user cost, thew difficulties do not arise. The reader is advised, however, to await the fuller discussion in Chapter 6 and its appendix.

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Chapter 2
The Postulates of the Classical Economics



MOST treatises on the theory of value and production are primarily concerned with the distribution of a given volume of employed resources between different uses and with the conditions which, assuming the employment of this quantity of resources, determine their relative rewards and the relative values of their products.


The question, also, of the volume of the available resources, in the sense of the size of the employable population, the extent of natural wealth and the accumulated capital equipment, has often been treated descriptively.


But the pure theory of what determines the actual employment of the available resources has seldom been examined in great detail.


To say that it has not been examined at all would, of course, be absurd.


For every discussion concerning fluctuations of employment, of which there have been many, has been concerned with it.


I mean, not that the topic has been overlooked, but that the fundamental theory underlying it has been deemed so simple and obvious that it has received, at the most, a bare mention.[2]



The classical theory of employment — supposedly simple and obvious — has been based. I think, on two fundamental postulates, though practically without discussion, namely:



i. The wage is equal to the marginal product of labour
i. 賃金は労働の境界製品に等しい

That is to say, the wage of an employed person is equal to the value which would be lost if employment were to be reduced by one unit (after deducting any other costs which this reduction of output would avoid); subject, however, to the qualification that the equality may be disturbed, in accordance with certain principles, if competition and markets are imperfect.



ii. The utility of the wage when a given volume of labour is employed is equal to the marginal disutility of that amount of employment.
ii. 与えられた労働の量が使用されたときの賃金の効用は、使用の量の境界不効用に等しい。


That is to say, the real wage of an employed person is that which is just sufficient (in the estimation of the employed persons themselves) to induce the volume of labour actually employed to be forthcoming;



subject to the qualification that the equality for each individual unit of labour may be disturbed by combination between employable units analogous to the imperfections of competition which qualify the first postulate.



Disutility must be here understood to cover every kind of reason which might lead a man, or a body of men, to withhold their labour rather than accept a wage which had to them a utility below a certain minimum.



This postulate is compatible with what may be called ‘frictional’ unemployment.


For a realistic interpretation of it legitimately allows for various inexactnesses of adjustment which stand in the way of continuous full employment:


for example, unemployment due to a temporary want of balance between the relative quantities of specialised resources as a result of miscalculation or intermittent demand;


or to time-lags consequent on unforeseen changes; or to the fact that the change-over from one employment to another cannot be effected without a certain delay, so that there will always exist in a non-static society a proportion of resources unemployed ‘between jobs’.



In addition to ‘frictional’ unemployment, the postulate is also compatible with ‘voluntary’ unemployment due to the refusal or inability of a unit of labour, as a result of legislation or social practices or of combination for collective bargaining or of slow response to change or of mere human obstinacy, to accept a reward corresponding to the value of the product attributable to its marginal productivity.


But these two categories of ‘frictional’ unemployment and ‘voluntary’ unemployment are comprehensive.


The classical postulates do not admit of the possibility of the third category, which I shall define below as ‘involuntary’ unemployment.



Subject to these qualifications, the volume of employed resources is duly determined, according to the classical theory, by the two postulates.


The first gives us the demand schedule for employment, the second gives us the supply schedule;



and the amount of employment is fixed at the point where the utility of the marginal product balances the disutility of the marginal employment.


It would follow from this that there are only four possible means of increasing employment:


(a) An improvement in organisation or in foresight which diminishes ‘frictional’ unemployment;

(a) 組織の改善、または’摩擦的’失業をなくす展望の改善

(b) a decrease in the marginal disutility of labour, as expressed by the real wage for which. additional labour is available, so as to diminish ‘voluntary’ unemployment;

(b) 真の賃金と表現される労働の境界不効用の減少、その真の賃金のために追加的労働は’自発的’失業をなくすために利用可能である。

(c) an increase in the marginal physical productivity of labour in the wage-goods industries (to use Professor Pigou’s convenient term for goods upon the price of which the utility of the money-wage depends);

(c) 賃金財産業における労働の境界物理的生産性の増加(賃金財産業ってのはピグー教授の便利な用語で、カネ賃金の効用が依存している商品の価格のこと)

(d) an increase in the price of non-wage-goods compared with, the price of wage-goods, associated with a shift in the expenditure of non-wage-earners from wage-goods to non-wage-goods.

(d) 非賃金財の価格の増加、賃金財と比較して、賃金財から非賃金財への非賃金所有者の支出の変化と結びついている。


This, to the best of my understanding, is the stance of Professor Pigou’s Theory of Unemployment — the only detailed account of the classical theory of employment which exists.


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Chapter 1


The General Theory


I HAVE called this book the General Theory of Employment, Interest and Money, placing the emphasis on the prefix general.


The object of such a title is to contrast the character of my arguments and conclusions with those of the classical[1] theory of the subject, upon which I was brought up and which dominates the economic thought, both practical and theoretical, of the governing and academic classes of this generation, as it has for a hundred years past.


I shall argue that the postulates of the classical theory are applicable to a special case only and not to the general case, the situation which it assumes being a limiting point of the possible positions of equilibrium.


Moreover, the characteristics of the special case assumed by the classical theory happen not to be those of the economic society which we actually live, with the result that its teaching is misleading and disastrous if we attempt to apply it to the facts of experience.



1. “The classical economists” was a name invented by Marx to cover Ricardo and James Mill and their predecessors, that is to say for the founders of the theory which culminated in the Ricardian economics.


I have become accustomed, perhaps perpetrating a solecism, to include in “the classical school” the followers of Ricardo, those, that is to say, who adopted and perfected the theory of the Ricardian economics, including (for example) J. S. Mill, Marshall, Edgeworth and Prof. Pigou.



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The composition of this book has been for the author a long struggle of escape, and so must the reading of it be for most readers if the author’s assault upon them is to be successful,— a struggle of escape from habitual modes of thought and expression.



The ideas which are here expressed so laboriously are extremely simple and should be obvious.


The difficulty lies, not in the new ideas, but in escaping from the old ones, which ramify, for those brought up as most of us have been, into every corner of our minds.


J. M. Keynes


December 13, 1935


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The writer of a book such as this, treading along unfamiliar paths, is extremely dependent on criticism and conversation if he is to avoid an undue proportion of mistakes.


It is astonishing what foolish things one can temporarily believe if one thinks too long alone, particularly in economics (along with the other moral sciences), where it is often impossible to bring one’s ideas to a conclusive test either formal or experimental.



In this book, even more perhaps than in writing my Treatise on Money, I have depended on the constant advice and constructive criticism of Mr. R. F. Kahn.


There is a great deal in this book which would not have taken the shape it has except at his suggestion.


I have also had much help from Mrs. Joan Robinson, Mr. R. G. Hawtrey and Mr. R. F. Harrod, who have read the whole of the proof-sheets.


The index has been compiled by Mr. D. M. Bensusan-Butt of King’s College, Cambridge.


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The relation between this book and my Treatise on Money, which I published five years ago, is probably clearer to myself than it will be to others;


and what in my own mind is a natural evolution in a line of thought which I have been pursuing for several years, may sometimes strike the reader as a confusing change of view.


これも英語として難しい。may sometimes ~の主語はwhat in my own midでいいのか。

This difficulty is not made less by certain changes in terminology which I have felt compelled to make.


These changes of language I have pointed out in the course of the following pages;



but the general relationship between the two books can be expressed briefly as follows.


When I began to write my Treatise on Money I was still moving along the traditional lines of regarding the influence of money as something so to speak separate from the general theory of supply and demand.


When I finished it, I had made some progress towards pushing monetary theory back to becoming a theory of output as a whole.


theory of output as a wholeが何を意味しているのか勉強してないのでわからない。

But my lack of emancipation from preconceived ideas showed itself in what now seems to me to be the outstanding fault of the theoretical parts of that work (namely, Books III and IV), that I failed to deal thoroughly with the effects of changes in the level of output.


level of outputとはなんだろうか。levelという位だから高々量のことではないし、量というのを何らかの基準で分けたもののことだろうか?

My so-called “fundamental equations” were an instantaneous picture taken on the assumption of a given output.



They attempted to show how, assuming the given output, forces could develop which involved a profit-disequilibrium, and thus required a change in the level of output.



But the dynamic development, as distinct from the instantaneous picture, was left incomplete and extremely confused.



This book, on the other hand, has evolved into what is primarily a study of the forces which determine changes in the scale of output and employment as a whole;


and, whilst it is found that money enters into the economic scheme in an essential and peculiar manner, technical monetary detail falls into the background.



A monetary economy, we shall find, is essentially one in which changing views about the future are capable of influencing the quantity of employment and not merely its direction.



But our method of analysing the economic behaviour of the present under the influence of changing ideas about the future is one which depends on the interaction of supply and demand, and is in this way linked up with our fundamental theory of value.



We are thus led to a more general theory, which includes the classical theory with which we are familiar, as a special case.


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The matters at issue are of an importance which cannot be exaggerated.



But, if my explanations are right, it is my fellow economists, not the general public, whom I must first convince.


At this stage of the argument the general public, though welcome at the debate, are only eavesdroppers at an attempt by an economist to bring to an issue the deep divergences of opinion between fellow economists which have for the time being almost destroyed the practical influence of economic theory, and will, until they are resolved, continue to do so.

議論のこのレベルでは一般大衆は視聴者–もちろん討論は歓迎するが–だけであるでる。彼らは経済学者の企てによって、仲間の経済学者達–長年 にわたり経済理論の実際の影響をほとんど破壊してしまった–の意見と彼らのそれを解決するまで続けようとする意思との間の深い亀裂を問題にしようとして いる。


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THIS book is chiefly addressed to my fellow economists.


I hope that it will be intelligible to others.


But its main purpose is to deal with difficult questions of theory, and only in the second place with the applications of this theory to practice.


For if orthodox economics is at fault, the error is to be found not in the superstructure, which has been erected with great care for logical consistency, but in a lack of clearness and of generality in the premisses.



Thus I cannot achieve my object of persuading economists to re-examine critically certain of their basic assumptions except by a highly abstract argument and also by much controversy.


I wish there could have been less of the latter.


But I have thought it important, not only to explain my own point of view, but also to show in what respects it departs from the prevailing theory.


Those, who are strongly wedded to what I shall call “the classical theory”, will fluctuate, I expect, between a belief that I am quite wrong and a belief that I am saying nothing new.


It is for others to determine if either of these or the third alternative is right.


My controversial passages are aimed at providing some material for an answer;


and I must ask forgiveness if, in the pursuit of sharp distinctions, my controversy is itself too keen.



I myself held with conviction for many years the theories which I now attack, and I am not, I think, ignorant of their strong points.