# William Stanley Jevons

William Stanley Jevons (1 September 1835 – 13 August 1882) was an English economist and logician.

## Quotes

* You will perceive that economy, scientifically speaking, is a very contracted science; it is in fact a sort of vague mathematics which calculates the causes and effects of man's industry, and shows how it may be best applied. There are a multitude of allied branches of knowledge connected with mans condition; the relation of these to political economy is analogous to the connexion of mechanics, astronomy, optics, sound, heat, and every other branch more or less of physical science, with pure mathematics.
** Letter to Henrietta Jevons (28 February 1858), published in Letters and Journal of W. Stanley Jevons (1886), edited by Harriet A. Jevons, his wife, p. 101.
* One of the most important axioms is, that as the quantity of any commodity, for instance, plain food, which a man has to consume, increases, so the utility or benefit derived from the last portion used decreases in degree. The decrease in enjoyment between the beginning and the end of a meal may be taken as an example. And I assume that on an average, the ratio of utility is some continuous mathematical function of the quantity of commodity. This law of utility has, in fact, always been assumed by political economists under the more complex form and name of the Law of Supply and Demand. But once fairly stated in its simple form, it opens up the whole of the subject.
** Letter to his brother (1 June 1860), published in Letters and Journal of W. Stanley Jevons (1886), edited by Harriet A. Jevons, his wife, p. 151.
* When quite young I can remember I had no thought or wish of surpassing others. I was rather taken with a liking of little arts and bits of learning. My mother carefully fostered a liking for botany, giving me a small microscope and many books, which I yet have. Strange as it may seem, I now believe that botany and the natural system, by exercising discrimination of kinds, is the best of logical exercises. What I may do in logic is perhaps derived from that early attention to botany.
** Reflections on his earlier life, written when he was 27 (December 1862), published in Letters and Journal of W. Stanley Jevons (1886), edited by Harriet A. Jevons, his wife, p. 11.
* I used to think I should like to be a bookbinder or bookseller it seemed to me a most delightful trade and I wished or thought of nothing better. More lately I thought I should be a minister, it seemed so serious and useful a profession, and I entered but little into the merits of religion and the duties of a minister. Every one dissuaded me from the notion, and before I arrived at any age to require a real decision, science had claimed me.
** Reflections on his earlier life, written when he was 27 (December 1862), published in Letters and Journal of W. Stanley Jevons (1886), edited by Harriet A. Jevons, his wife, p. 12.
* It was during the year 1851, while living almost unhappily among thoughtless, if not bad companions, in Gower Street a gloomy house on which I now look with dread it was then, and when I had got a quiet hour in my small bedroom at the top of the house, that I began to think that I could and ought to do more than others. A vague desire and determination grew upon me. I was then in the habit of saying my prayers like any good church person, and it was when so engaged that I thought most eagerly of the future, and hoped for the unknown. My reserve was so perfect that I suppose no one had the slightest comprehension of my motives or ends. My father probably knew me but little. I never had any confidential conversation with him. At school and college the success in the classes was the only indication of my powers. All else that I intended or did was within or carefully hidden. The reserved character, as I have often thought, is not pleasant nor lovely. But is it not necessary to one such as I? Would it have been sensible or even possible for a boy of fifteen or sixteen to say what he was going to do before he was fifty? For my own part I felt it to be almost presumptuous to pronounce to myself the hopes I held and the schemes I formed. Time alone could reveal whether they were empty or real; only when proved real could they be known to others.
** Reflections on his earlier life, written when he was 27 (December 1862), published in Letters and Journal of W. Stanley Jevons (1886), edited by Harriet A. Jevons, his wife, p. 13.
* I cannot consent with the Radical party to obliterate a glorious past, nor can I consent with the Conservatives to prolong abuses into the present. I wish with all my heart to aid in securing all that is good for the masses, yet to give them all they wish and are striving for is to endanger much that is good beyond their comprehension. I cannot pretend to underestimate the good that the English monarchy and aristocracy, with all the liberal policy actuating it, does for the human race, and yet I cannot but fear the pretensions of democracy against it are strong, and in some respects properly strong. This antithesis and struggle, perhaps, after all, is no more than has always more or less existed, but is now becoming more marked. Compromise, perhaps, is the only resource. Those who rightly possess the power in virtue of their superior knowledge must yield up some, that they may carry with them the honest but uncertain wills of those less educated but more numerous and physically powerful.
** Journal (November 1866) following criticism from "the Radicals" of his Oct. 12 lecture "On the Diffusion of a Knowledge of Political Economy." Letters and Journal of W. Stanley Jevons (1886) pp. 230-231.
* Pray accept my best thanks for your kindness in sending me a copy of your Memoir, and for the very courteous letter in which you draw my attention to it. When your letter came I had, indeed, already noticed in the Journal des Economistes your very remarkable theory. I felt the greater interest in the subject because my own speculations have led me in the same direction, now for the last twelve years or more. It is satisfactory to me to find that my theory of exchange, which, when published in England, was either neglected or criticised, is practically confirmed by your researches. I do not know whether you are acquainted with my writings on the subject. All the chief points of my mathematical theory were clear to my own mind by the year 1862, when I drew up a brief account of it, which was read at the meeting of the British Association at Cambridge... A very brief abstract was then alone inserted in the report, but the original paper was printed in the journal of the London Statistical Society in 1866... Finally, in 1871, I caused to be published... the Theory of Political Economy, in which is given a full explanation of the theory, with the aid of mathematical symbols. [...] You will find, I think, that your theory substantially coincides with and confirms mine, although the symbols are differently chosen, and there are incidental variations. You will see that the whole theory rests on the notion... that the utility of a commodity is not proportional to its quantity; what you call the rarity of a commodity appears to be exactly what I called the coefficient of utility at first, and afterwards the degree of utility, which... was really the differential coefficient of the utility considered as the function of the quantity of commodity. The theory of exchange is given... and may be considered to be contained in one sentence. An equation may thus be established on either side between the utility gained and sacrificed at the ratio of exchange of the whole commodities, upon the last increments exchanged. Now in my book of 1871, I show fully how this theory may be expressed in symbols. [...] Indeed, when the meaning of the terms is explained, your proposition 'Les prix courants ou prix d'equilibre sont égaux aux rapports des raretés' is seen to coincide precisely with my theory, except that you do not point out how many equations are requisite, or how many unknown quantities there are. The publication of your paper... tends to confirm my belief in the correctness of the theory, but it might lead to misapprehensions as to the originality and priority... I shall therefore take it as a favour if you will kindly inform me whether you are sufficiently acquainted with my writings, or whether you would desire me to forward a copy of my Theory of Political Economy.
** Letter to Léon Walras (May 12, 1874) Letters and Journal of W. Stanley Jevons (1886) pp. 302-304.
* I need hardly stay to demonstrate that facts are valueless unless connected and explained by a correct theory; that analogies are very dangerous grounds of inference, unless carefully founded on similar conditions; and that experience misleads if it be misinterpreted.
** "The Railways and the State." In Essays and Addresses, Macmillan & Co., 1874, page 467.

### The Coal Question (1865)

* Coal in truth stands not beside, but entirely above, all other commodities. It is the material source of the energy of the country—the universal aid—the factor in everything we do. With coal almost any feat is possible or easy; without it we are thrown back into the laborious poverty of earlier times.
* It is very commonly urged, that the failing supply of coal will be met by new modes of using it efficiently and economically. ...It is wholly a confusion of ideas to suppose that the economical use of fuel is equivalent to a diminished consumption. The very contrary is the truth.
* Commerce is but a means to an end, the diffusion of civilization and wealth. To allow commerce to proceed until the source of civilization is weakened and overturned is like killing the goose to get the golden egg. Is the immediate creation of material wealth to be our only object?
* Have we not hereditary possessions in our just laws, our free and nobly developed constitution, our rich literature and philosophy, incomparably above material wealth, and which we are beyond all things bound to maintain, improve, and hand down in safety? And do we accomplish this duty in encouraging a growth of industry which must prove unstable, and perhaps involve all things in its fall?
* The alternatives before us are simple. Our empire and race already comprise one-fifth of the world's population, and by our plantation of new states, by our guardianship of the seas, by our penetrating commerce, by the example of our just laws and firm constitution, and above all by the dissemination of our new arts, we stimulate the progress of mankind in a degree not to be measured. If we lavishly and boldly push forward in the creation and distribution of our riches, it is hard to over-estimate the pitch of beneficial influence to which we may attain in the present. But the maintenance of such a position is physically impossible. We have to make the momentous choice between brief greatness and longer continued mediocrity.

### The Substitution of Similars, The True Principles of Reasoning (1869)

* All acts of reasoning seem to me to be different cases of one uniform process which may perhaps be best described as the substitution of similars. ..The chief difficulty consists in showing that all the forms of the old logic, as well as the fundamental rules of mathematical reasoning, may be explained upon the same principle; and it is to this difficult task I have devoted the most attention.
** Preface
* The new and wonderful results of the late Dr. Boole's mathematical system of Logic appear to develop themselves as most plain and evident consequences of the self-same process of substitution, when applied to the Primary Laws of Thought. Should my notion be true, a vast mass of technicalities may be swept from our logical text-books, and yet the small remaining part of logical doctrine will prove far more useful than all the learning of the Schoolmen.
** Preface
* Aristotle's dictim... may then be formulated somewhat as follows:—Whatever is known of a term may be stated of its equal or equivalent. Or, in other words, Whatever is true of a thing is true of its like. ...the value of the formula must be judged by its results; ...it not only brings into harmony all the branches of logical doctrine, but... unites them in close analogy to the corresponding parts of mathematical method. All acts of mathematical reasoning may... be considered but as applications of a corresponding axiom of quantity...

### Elementary Lessons on Logic (1870)

* Logic is not only an exact science, but is the most simple and elementary of all sciences; it ought therefore undoubtedly to find some place in every course of education.
** Preface.
* Logic should no longer be considered an elegant and learned accomplishment; it should take its place as an indispensable study for every well-informed person.
** Preface.
* The laws of thought are natural laws with which we have no power to interfere, and which are of course not to be in any way confused with the artificial laws of a country, which are invented by men and can be altered by them. Every science is occupied in detecting and describing the natural laws which are inflexibly observed by the objects treated in the Science.
** Introduction, Lesson I: Definition and Sphere of the Science.

### The Theory of Political Economy (1871)

    Quotations from the 2nd edition (1879)
* There are many portions of economical doctrine which appear to me as scientific in form as they are consonant with facts.
** Preface To The First Edition, p. 3.
* In this work I have attempted to treat economy as a calculus of pleasure and pain, and have sketched out,almost irrespective of previous opinions, the form which the science,as it seems to me, must ultimately take.
** Preface To The First Edition, p. 4.
* A correspondent, Captain Charles Christie R.E., to whom I have shown these sections after they were printed, objects reasonably enough that commodity should not have been represented by M, or Mass, but by some symbol, for instance Q, which would include quantity of space or time or force, in fact almost any kind of quantity.
** Preface To The Second Edition, p. 6.
* In short, I do not write for mathematicians, nor as a mathematician, but as an economist wishing to convince other economists that their science can only be satisfactorily treated on an explicitly mathematical basis.
** Preface To The Second Edition, p. 7.
* Among minor alterations, I may mention the substitution for the name political economy of the single convenient term economics. I cannot help thinking that it would be well to discard, as quickly as possible, the old troublesome double-worded name of our science.
** Preface To The Second Edition, p. 8.
* In any case I hold that there must arise a science of the development of economic forms and relations.
** Preface To The Second Edition, p. 9.
* As there are so many who talk prose without knowing it, or, again, who syllogize without having the least idea what a syllogism is, so economists have long been mathematicians without being aware of the fact.
** William Stanley Jevons, The Theory of Political Economy (1871). Preface To The Second Edition, p. 14.
* The conclusion to which I am ever more clearly coming is that the only hope of attaining a true system of economics is to fling aside,once and forever, the mazy and preposterous assumptions of the Ricardian school. Our English economists have been living in a fool's paradise. The truth is with the French school, and the sooner we recognize the fact, the better it will be for all the world, except perhaps the few writers who are far too committed to the old erroneous doctrines to allow for renunciation.
** Preface To The Second Edition, p. 27-28.
* Property is only another name for monopoly.
** Preface To The Second Edition, p. 29.
* Thus monopoly is limited by competition, and no owner, whether of labour, land or capital, can, theoretically speaking,obtain a larger share of produce for it than what other owners of exactly the same kind of property are willing to accept.
** Preface To The Second Edition, p. 29.
* There is no such thing as absolute cost of labour; it is all a matter of comparison. Every one gets the most which he can for his exertions; some can get little or nothing, because they have not sufficient strength, knowledge or ingenuity; others get much, because they have, comparatively speaking, a monopoly of certain powers.
** Preface To The Second Edition, p. 31.
* Repeated reflection and inquiry have led me to the somewhat novel opinion, that value depends entirely upon utility.
** Chapter I, Introduction, p. 37.
* It is clear that economics, if it is to be a science at all, must be a mathematical science.
** Chapter I, Introduction, p. 38.
* but, in reality, there is no such thing as an exact science.
** Chapter I, Introduction, p. 40.
* Previous to the time of Pascal, who would have thought of measuring doubt and belief? Who could have conceived that the investigation of petty games of chance would have led to the most sublime branch of mathematical science - the theory of probabilities?
** Chapter I, Introduction, p. 41.
* A correct theory is the first step towards improvement, by showing what we need and what we might accomplish.
** Chapter I, Introduction, p. 44.
* The theory which follows is entirely based on a calculus of pleasure and pain; and the object of economics is to maximize happiness by purchasing pleasure, as it were, at the lowest cost of pain.
** Chapter I, Introduction, p. 51.
* The calculus of utility aims at supplying the ordinary wants of man at the least cost of labour.
** Chapter I, Introduction, p. 53.
* PLEASURE and pain are undoubtedly the ultimate objects of the calculus of economics. To satisfy our wants to the utmost with the least effort - to procure the greatest amount of what is desirable at the expense of the least that is undesirable - in other words, to maximize pleasure, is the problem of economics.
** Chapter III, Theory of Utility, p. 61.
* By a commodity we shall understand any object, substance, action or service, which can afford pleasure or ward off pain.
** Chapter III, Theory of Utility, p. 61.
* My principal work now lies in tracing out the exact nature and conditions of utility. It seems strange indeed that economists have not bestowed more minute attention on a subject which doubtless furnishes the true key to the problems of economics.
** Chapter III, Theory of Utility, p. 65.
* One of the first and most difficult steps in a science is to conceive clearly the nature of the magnitudes about which we are arguing.
** Chapter III, Theory of Utility, p. 78.
* The difficulties of economics are mainly the difficulties of conceiving clearly and fully the conditions of utility.
** Chapter III, Theory of Utility, p. 82.
* "that in the same open market, at any one moment, there cannot be two prices for the same kind of article,"
** Chapter IV, Theory of Exchange, p. 97.
* Economists can never be free of from difficulties unless they will distinguish between a theory and the application of a theory.
** Chapter IV, Theory of Exchange, p. 108.
* We shall never have a science of economics unless we learn to discern the operation of law even among the most perplexing complications and apparent interruptions.
** Chapter IV, Theory of Exchange, p. 110.
* Over-production is not possible in all branches of industry at once, but it is possible in some as compared to others.
** Chapter V, Theory of Labour, p. 172.
* A spade may be made of any size, and if the same number of strokes be made in the hour, the requisite exertion will vary nearly as the cube of the length of the blade.
** Chapter V, Theory of Labour, p. 173.
* Ina regular and constant employment the greatest result will always be gained by such a rate as allows a workman each day,or each week at the most, to recover all fatigue and recommence with an undiminished store of energy.
** Chapter V, Theory of Labour, p. 176.
* An isolated man like Alexander Selkirk might feel the benefit of a stock of provisions, tools and other means of facilitating industry, although cut off from traffic, with other men.
** Chapter VII, Theory of Capital, p. 185.
* Capital simply allows us to expend labour in advance.
** Chapter VII, Theory of Capital, p. 187.
* What capital I give for the spade merely replaces what the manufacturer had already invested in the expectation that the spade would be needed.
** Chapter VII, Theory of Capital, p. 188.
* One pound invested for five years gives the same result as five pounds invested for one year, the product being five pound years.
** Chapter VII, Theory of Capital, p. 190.
* The whole result of continued labour is not often consumed and enjoyed in a moment; the result generally lasts for a certain length of time. We must then conceive the capital as being progressively uninvested.
** Chapter VII, Theory of Capital, p. 191.
* Some of the gold possessed by the Romans is doubtless mixed with what we now possess; and some small part of it will be handed down as long as the human race exists.
** Chapter VII, Theory of Capital, p. 198.
* I consider that interest is determined by the increment of produce which it enables a labourer to obtain, and is altogether independent of the total return which he receives for this labour.
** Chapter VII, Theory of Capital, p. 206.
* I feel quite unable to adopt the opinion that the moment goods pass into the possession of the consumer they cease altogether to have the attributes of capital.
** Chapter VII, Theory of Capital, p. 209.
* "we often observe that there is abundance of capital to be had at low rates of interest, while there are also large numbers of artisans starving for want of employment."
** Chapter VIII, Concluding Remarks, p. 215.
* To me it is far more pleasant to agree than to differ; but it is impossible that one who has any regard for truth can long avoid protesting against doctrines which seem to him to be erroneous. There is ever a tendency of the most hurtful kind to allow opinions to crystallise into creeds. Especially does this tendency manifest itself when some eminent author, enjoying power of clear and comprehensive exposition, becomes recognised as an authority. His works may perhaps be the best which are extant upon the subject in question; they may combine more truth with less error than we can elsewhere meet. But "to err is human," and the best works should ever be open to criticism. If, instead of welcoming inquiry and criticism, the admirers of a great author accept his writings as authoritative, both in their excellences and in their defects, the most serious injury is done to truth. In matters of philosophy and science authority has ever been the great opponent of truth. A despotic calm is usually the triumph of error. In the republic of the sciences sedition and even anarchy are beneficial in the long run to the greatest happiness of the greatest number.
** Chapter VIII : Concluding Remarks, The Noxious Influence of Authority, p. 220.
* Truth indeed is sacred; but, as Pilate said, "What is truth?" Show us the undoubted infallible criterion of absolute truth, and we will hold it as a sacred inviolable thing. But in the absence of that infallible criterion, we have all an equal right to grope about in our search of it, and no body and no school nor clique must be allowed to set up a standard of orthodoxy which shall bar the freedom of scientific inquiry.
** Chapter VIII : Concluding Remarks, The Noxious Influence of Authority, p. 220.
* I protest against deference to any man, whether John Stuart Mill, or Adam Smith, or Aristotle, being allowed to check inquiry. Our science has become far too much a stagnant one, in which opinions rather than experience and reason are appealed to.
** Chapter VIII : Concluding Remarks, The Noxious Influence of Authority, p. 221.

### The Principles of Science: A Treatise on Logic and Scientific Method (1874) Vol. 1

* In a certain sense all knowledge is inductive. We can only learn the laws and relations of things in nature by observing those things. But the knowledge gained from the senses is knowledge only of particular facts, and we require some process of reasoning by which we may collect out of the facts the laws obeyed by them. Experience gives us the materials of knowledge: induction digests those materials, and yields us general knowledge. When we possess such knowledge, in the form of general propositions and natural laws, we can usefully apply the reverse process of deduction to ascertain the exact information required at any moment. In its ultimate foundation, then, all knowledge is inductive—in the sense that it is derived by a certain inductive reasoning from the facts of experience.
** p. 14
* I shall endeavor to show that induction is really the inverse process of deduction.
** p. 14
* Neither in deductive nor inductive reasoning can we add a tittle to our implicit knowledge, which is like that contained in an unread book or a sealed letter. ...Reasoning explicates or brings to conscious possession what was before unconscious. It does not create, nor does it destroy, but it transmutes and throws the same matter into a new form.
** p. 136
* Nature is to us like an inﬁnite ballot-box, the contents of which are being continually drawn, ball after ball, and exhibited to us. Science is but the careful observation of the succession in which balls of various character present themselves; we register the combinations, notice those which seem to be excluded from occurrence, and from the proportional frequency of those which usually appear we infer the probable character of future drawings.
** p. 169
* By induction we gain no certain knowledge; but by observation, and the inverse use of deductive reasoning, we estimate the probability that an event which has occurred was preceded by conditions of specified character, or that such conditions will be followed by the event. ...I have no objection to use the words cause and causation, provided they are never allowed to lead us to imagine that our knowledge of nature can attain to certainty. ...We can never recur too often to the truth that our knowledge of the laws and future events of the external world are only probable.
** pp. 257, 260 & 271

### Investigations in Currency and Finance (1884)

* And then the difference seems to arise from the deficient harvest, from the growth of population, from the extortion of tradesmen, from anything rather than the change of a British sovereign fresh from the Mint. Value is the most invisible and impalpable of ghosts, and comes and goes unthought of while the visible and dense matter remains as it was.
** p. 80

## Quotes about Jevons

* George Boole took up Leibniz's idea, and wrote a book he called The Laws of Thought. The laws he formulated are now called Boolean algebra... William Stanley Jevons heard of Boole's work, and undertook to build a machine to make calculations in Boolean algebra. He successfully designed and built such a machine, which he called the Logical Piano, apparently because it was about the size and shape of a small piano. This machine and its creator deserve much more fanfare than they have so far received. This was the first machine to do mechanical inference. Its predecessors, including the [Leibniz] Stepped Reckoner, only did arithmetic. ...The design of the machine was described in On the Mechanical Performance of Logical Inference, read before the British Royal Society in 1870.
** Michael J. Beeson, "The Mechanization of Mathematics," in Alan Turing: Life and Legacy of a Great Thinker (2004)

## External links

* "William Stanley Jevons", at the MacTutor History of Mathematics archive
* New School: William Stanley Jevons
* Royal Society certificate of election 1872
* "Jevons and the Logic 'Piano'" at The Rutherford Journal
* Elementary Lessons in Logic (1888) pdf @mises.org
* The Substitution of Similars (1869) @GoogleBooks
* The Theory of Political Economy (1879) 2nd ed. @GoogleBooks
Some of Jevons's works are available on the Library of Economics and Liberty website
* The Coal Question (also available here)
* The Theory of Political Economy
* Money and the Mechanism of Exchange
* Richard Cantillon and the Nationality of Political Economy
A few more on the Archive for the History of Economic Thought website
* William Stanley Jevons