Lord Kelvin
Formulated the first and second laws of thermodynamics and proposed the absolute temperature scale.
Most quoted
"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."
— from Popular Lectures and Addresses, Vol. I, 1883
"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."
— from Popular Lectures and Addresses, Vol. I, 1883
"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 a science."
— from Speech, 1889
All quotes by Lord Kelvin (356)
The dissipation of energy.
Fourier's theorem is not only one of the most beautiful results of modern analysis, but it may be said to furnish an indispensable instrument in the treatment of nearly every recondite question in pure or applied mathematics.
I have no satisfaction in the fact that science has been proved right; I only feel sorrow that it has taken so long to prove it.
The soul of man is immortal and imperishable.
In the study of nature, there is nothing so repulsive as a want of measure and proportion.
The true logic of navigation is retirement.
We cannot define electricity, but we can measure it.
The age of the earth is 100 million years.
Telegraphy without wires.
The steam engine is the glory of the industrial age.
In physical science, a first essential step in the direction of learning any subject is to find principles of numerical reckoning and methods for practically measuring some quality connected with it.
Life is a transient dream.
The harmony of the world is made manifest in Form and Number.
Quaternions came from Hamilton after his really good work had been done; and though beautifully ingenious, have been an unmixed evil to those who have touched them in physics.
I want to know how God created this world. I am not interested in this or that phenomenon. I want to know His thoughts; the rest are details.
The smallest portions of matter cannot be annihilated; they can only be changed in form.
My notion of the structure of the universe is this: there is a single infinite ocean of pure mathematics, in which there is no difference between matter and mind.
As we conquer peak after peak we find that the universe is full of surprises.
The man who cannot believe in God cannot believe in anything.
On his deathbed: I have been looking into the second volume of the 'Encyclopaedia Britannica.'
Contemporaries of Lord Kelvin
Other Physicss born within 50 years of Lord Kelvin (1824–1907).