Born in Liverpool, 1st September 1835, studied there and in London. Assayer to Sydney mint 1854–59, in 1866 he became professor of Logic and Political Economy at Owens College, Manchester, and in 1876–81 held the chair of Political Economy at University College, London. He was drowned 13th August 1882 whilst bathing at Bexhill, near Hastings. Jevons popularised the mathematical methods of Boole, and wrote “Elementary Lessons in Logic” (1870); “Principles of Science” (1874), “Studies in Deductive Logic” (1880), and “Pure Logic and other Minor Works” (1890). To the science of political economy he contributed “The Coal Question” (1865), which led to the appointment of a Royal Commission, and “Theory of Political Economy” (1871; 3d ed. 1888). See his “Letters and Journals,” edited by his wife (1886).

Personal

  A philosophic mildness irradiated his private life. His friends and all who consulted him in their difficulties experienced that the wisest was also the kindest of men. Those who know nothing of him but his books should learn that it was only in his controversial writing that the appearance of a sort of odium logicum might seem to overcast the serenity of his nature. After all, like Mr. Butler in the “Heart of Midlothian,” he was a man and had been a teacher. The imposed necessity of using Mill’s writings as text-books may have led him at once to scan minutely the faults and to estimate too extravagantly the influence of his great predecessor, till at last he burst out—“I will no longer consent to live silently under the incumbus of bad logic and bad philosophy which Mill’s works have laid upon us.” There may have been here an error of judgment; but there never was an unworthy feeling of jealousy in the breast of the philosopher.

  Jevons was distinguished by a noble simplicity of disposition. In accordance with this, the key-note to his character, he was pious in the broadest sense of the word, tender-hearted, readily interested in whatever had a real human significance, and, notwithstanding, a constitutional tendency to depression, very easily pleased and amused. Both intellectually and morally self-centred, he was entirely free from sordid ambition, and from the mere love of applause. No more honest man ever achieved fame while living laborious days, and striving from his boyhood upward to become “a powerful good in the world.”

General

  In him an antique boldness of theory was complemented by the cautious spirit of Baconian investigation. He seemed to see with equal eye the general and the particular. Of him alone it would be difficult to say that he looked on one side of truth’s shield more readily than the other…. At the basis of his system, as the ground work of his magnificent “Principles of Science,” he placed Logic. He took a mathematical pleasure in manipulating her empty forms…. The abstract nature of Prof. Jevons’ intellect, instinctively flying to the highest generalisations, is conspicuous in his daring attempt to apply mathematics to political economy. Of course the attempt stands condemned beforehand by dull routine and littérateur pertness—profoundly ignorant of the methods of mathematics…. Coming to the more ordinary level of abstraction, in the region of “Middle Axiom,” we shall find more universally conspicuous monuments of genius in Prof. Jevons’ splendid investigations on the “Fall in the Value of Gold,” the “Coal Question,” and a series of some fifty papers of the highest economical and statistical value. In such publications as formed part of educational or scientific series, the scientific primer of Political Economy, and the volume on “Money” he showed his unrivalled power of making dry subjects attractive and even amusing.

  Some of his equations are perhaps useful as a concise mode of expression: others appear to illustrate the impossibility of dealing with abstract ideas by mathematical processes. He is, consequently, often credited with the obviously absurd theory that the ultimate criterion of value is the current estimation of a commodity, or, to use the ill-chosen Jevonian expression, “the final degree of utility.” Such a theory, like many others of a similar kind, would confound the essence or the substance of a thing with its mere phenomenal expression or manifestation. No one denies, or ever has denied, that supply and demand enter into the temporary value or the price of anything, but this is very different from confounding the mere expression of value in any particular instance with that value which constitutes the substance of every economic object, and without which that object could not be.

  The treatise on economics which Jevons had planned and partly written, and which he intended to make his magnum opus, will remain lost to the world. But he left behind him more than enough to warrant his European reputation as a statistician of vast industry and rare gifts of combination, and as an economist of high original power. In the opinion of Professor Alfred Marshall, the great body of Jevons’s economic work “will probably be found to have more constructive force than any save that of Ricardo that has been done during the last hundred years.” As a logician, he sought with considerable success to advance, as well as defend, the position taken up by Boole, and to establish the applicability of his theory of reasoning to all branches of scientific inquiry.

  Working on Boole’s system, William Stanley Jevons arrived at a more convenient symbolic method in his works “Pure Logic” (1864), “The Substitution of Similars” (1869), and “The Principles of Science” (1872). The last two of these belong chronologically to our next period, but are mentioned here because they are so closely associated with the preceding logical movement. In “The Principles of Science” Jevons does not deal merely with formal inferences, but goes over the ground traversed by Mill in his inductive logic. Competent critics are of the opinion that he displays more knowledge of actual scientific methods of investigation than Mill, but less philosophic insight.