I often say that when you can measure what you are speaking about, and — William Thomson

"He was one of the few scientists to be knighted, and the only one in the nineteenth century to be raised to the peerage. These honors, however, were not in recognition of his scientific work but his genius as an engineer in solving the major technical problems of laying the first Atlantic cable and his entrepreneurial success as an instrument designer and manufacturer for the new electrical industries and the Navy. With his success with the Atlantic cable Kelvin became a symbol of science to the general public."

"According to Sir W. Thomsons theory of Vortex Atoms, the substance of which the molecule consists is a uniformly dense plenum, the properties of which are those of a perfect fluid, the molecule itself being nothing but a certain motion impressed on a portion of this fluid, and this motion is shewn, by a theorem due to Helmholtz, to be as indestructible as we believe a portion of matter to be."

"The beauty and clearness of the dynamical theory, which asserts heat and light to be modes of motion, is at present obscured by two clouds. I. The first came into existence with the undulatory theory of light, and was dealt with by Fresnel and Dr. Thomas Young; it involved the question, how could the earth move through an elastic solid, such as essentially is the luminiferous ether? II. The second is the Maxwell–Boltzmann doctrine regarding the partition of energy."

"Thomson was a mathematical prodigy. At age 16, he mastered ’s and wrote and published a defense of it. Fourier’s theory allowed one to determine the distribution of heat in a body on the sole assumption that heat flow is proportional to temperature gradient. The approach was macroscopic, geometrical, and nonhypothetical, and Thomson took to it easily. During his undergraduate years at , he traveled to Paris and met the mathematical savants—in particular, mathematician Joseph Liouville and experimental physicist , who both considered Michael Faraday’s curved lines of force outré. At Liouville’s urging, Thomson produced for the a demonstration that the lines of force, whether electric or magnetic, followed from inverse square laws. The relevant mathematics was a near cousin to that for heat flow, but the insight was new and would be seminal in the thinking that led James Clerk Maxwell to electromagnetic field theory."

"It is conceivable that animal life might have the attribute of using the heat of surrounding matter, at its natural temperature, as a source of energy for mechanical effect . . . .The influence of animal or vegetable life on matter is infinitely beyond the range of any scientific enquiry hitherto entered on. Its power of directing the motions of moving particles, in the demonstrated daily miracle of our human free-will, and in the growth of generation after generation of plants from a single seed, are infinitely different from any possible result of the fortuitous concurrence of atoms."

"1. There is at present in the material world a universal tendency to the dissipation of mechanical energy. 2. Any restoration of mechanical energy, without more than an equivalent of dissipation, is impossible in inanimate material processes, and is probably never effected by means of organized matter, either endowed with vegetable life or subjected to the will of an animated creature. 3. Within a finite period of time past, the earth must have been, and within a finite period of time to come the earth must again be, unfit for the habitation of man as at present constituted, unless operations have been, or are to be performed, which are impossible under the laws to which the known operations going on at present in the material world are subject."

"In the life of the mass-order, the culture of the generality tends to conform to the demands of the average human being. Spirituality decays through being diffused among the masses when knowledge is impoverished in every possible way by rationalisation until it becomes accessible to the crude understanding of all."

"I say this to you because we Spaniards are a forgetful people, because we are used to living for the moment, because we do not look back, because we do not know how to see the chain of heroes, because we do not contemplate the sum of sacrifices."

"Sharon Tate was my best friend. Once, we were roommates. She introduced me to my husband. She was the godmother to my baby daughter who is named for her. In the six years time that I knew her, she never said an unkind word about anyone."

"Long time to see. (VS: Tapion)"

"Most mathematicians prove what they can, von Neumann proves what he wants." Once in a discussion about the rapid growth of mathematics in modern times, von Neumann was heard to remark that whereas thirty years ago a mathematician could grasp all of mathematics, that is impossible today. Someone asked him: "What percentage of all mathematics might a person aspire to understand today?" Von Neumann went into one of his five-second thinking trances, and said: "About 28 percent."

"Children must be free to think in all directions irrespective of the peculiar ideas of parents who often seal their childrens minds with preconceived prejudices and false concepts of past generations. Unless we are very careful, very careful indeed, and very conscientious, there is still great danger that our children may turn out to be the same kind of people we are."