William Thomson, 1st Baron Kelvin Quotes

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Symmetrical equations are good in their place, but 'vector' is a useless survival, or offshoot from quaternions, and has never been of the slightest use to any creature.

William Thomson, 1st Baron Kelvin
When you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind: it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science.

William Thomson, 1st Baron Kelvin
A scientific theory is a tool and not a creed.

William Thomson, 1st Baron Kelvin
Nothing can be more fatal to progress than a too confident reliance on mathematical symbols; for the student is only too apt to take the easier course, and consider the formula not the fact as the physical reality.

William Thomson, 1st Baron Kelvin
If the water flow down by a gradual natural channel, its potential energy is gradually converted into heat by fluid friction, according to an admirable discovery made by Mr Joule of Manchester above twelve years ago, which has led to the greatest reform that physical science has experienced since the days of Newton. From that discovery, it may be concluded with certainty that heat is not matter, but some kind of motion among the particles of matter; a conclusion established, it is true, by Sir Humphrey Davy and Count Rumford at the end of last century, but ignored by even the highest scientific men during a period of more than forty years.

William Thomson, 1st Baron Kelvin
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.

William Thomson, 1st Baron Kelvin
Considering the almost certain truth that the earth was built up of meteorites falling together, we may follow in imagination the whole process of shrinking from gaseous nebula to liquid lava and metals, and solidification of liquid from central regions outward.

William Thomson, 1st Baron Kelvin
Every process has laws, known or unknown, according to which it must take place. A consciousness of them is so far from being necessary to the process, that we cannot discover what they are, except by analyzing the results it has left us.

William Thomson, 1st Baron Kelvin
Tesla has contributed more to electrical science than any man up to his time.

William Thomson, 1st Baron Kelvin
To live among friends is the primary essential of happiness.

William Thomson, 1st Baron Kelvin
Paradoxes have no place in science. Their removal is the substitution of true for false statements and thoughts.

William Thomson, 1st Baron Kelvin
I want to understand light as well as I can, without introducing things that we understand even less of. That is why I take plain dynamics. I can get a model in plain dynamics; I cannot in electromagnetics.

William Thomson, 1st Baron Kelvin
It is impossible, by means of inanimate material agency, to derive mechanical effect from any portion of matter by cooling it below the temperature of the coldest of the surrounding objects.

William Thomson, 1st Baron Kelvin
I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be.

William Thomson, 1st Baron Kelvin
A perfect thermo-dynamic engine is such that, whatever amount of mechanical effect it can derive from a certain thermal agency; if an equal amount be spent in working it backwards, an equal reverse thermal effect will be produced.

William Thomson, 1st Baron Kelvin
These somewhat pedantic words are justifiable, because "infinitesimal satellite" is nine syllables to express three or four sentences; that is our justification.

William Thomson, 1st Baron Kelvin
When you are face to face with a difficulty, you are up against a discovery.

William Thomson, 1st Baron Kelvin
The stream lines are as represented in the annexed diagram, in which the region of translational velocity greater than wave-propagational velocity is separated from the region of translational velocity less than wave-propagational velocity by a cat's-eye border pattern of elliptic-whirls.

William Thomson, 1st Baron Kelvin
When you call a thing mysterious, all that means is that you don't understand it.

William Thomson, 1st Baron Kelvin
The hypothesis that life originated on this earth through moss-grown fragments from the ruins of another world may seem wild and visionary; all I maintain is that it is not unscientific.

William Thomson, 1st Baron Kelvin
A single curve, drawn in the manner of the curve of prices of cotton, describes all that the ear can possibly hear as a result of the most complicated musical performances.... That to my mind is a wonderful proof of the potency of mathematics.

William Thomson, 1st Baron Kelvin
It is impossible for a self-acting machine, unaided by any external agency, to convey heat from one body to another at a higher temperature.

William Thomson, 1st Baron Kelvin
There is... one thing I feel strongly in respect to investigation in physical or chemical laboratories — it leaves no room for shady, doubtful distinctions between truth, half-truth, whole falsehood. In the laboratory everything tested or tried is found true or not.

William Thomson, 1st Baron Kelvin
Do not imagine that mathematics is hard and crabbed, and repulsive to common sense. It is merely the etherealization of common sense.

William Thomson, 1st Baron Kelvin
Simplification of modes of proof is not merely an indication of advance in our knowledge of a subject, but is also the surest guarantee of readiness for farther progress.

William Thomson, 1st Baron Kelvin