William Stanley Jevons: Use

“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.”

William Stanley Jevons

Source: The Principles of Science: A Treatise on Logic and Scientific Method (1874) Vol. 1, p. 14

Law , Nature , Knowledge , Sense

“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.”

William Stanley Jevons book The Coal Question

The Coal Question (1865)
Context: 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.

Truth , Idea

“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.”

William Stanley Jevons

Preface
The Substitution of Similars, The True Principles of Reasoning (1869)
Context: 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.

Books , Learning , Parting

“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.”

William Stanley Jevons

Source: The Principles of Science: A Treatise on Logic and Scientific Method (1874) Vol. 1, pp. 257, 260 & 271

Truth , World , Law , Imagination

“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.”

William Stanley Jevons

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.

Age , Religion , Thinking , Decision

“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.”

William Stanley Jevons

Source: The Principles of Science: A Treatise on Logic and Scientific Method (1874) Vol. 1, p. 169

Nature , Appearance , Science , Success

“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.”

William Stanley Jevons

William Stanley Jevons 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 - 152.

Food

“Capital simply allows us to expend labour in advance.”

William Stanley Jevons The Theory of Political Economy

Source: The Theory of Political Economy (1871), Chapter VII, Theory of Capital, p. 187.

“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.”

William Stanley Jevons

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. https://archive.org/details/cu31924074297254/page/n168/mode/1up

Mathematics , Law , Food