In physical science a first essential step in the direction of learning any subject is to find principles of numerical reckoning and practicable methods for measuring some quality connected with it. 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.

[Referring to Fourier's mathematical theory of the conduction of heat] ... Fourier's great mathematical poem.

There is nothing in science which teaches the origin of anything at all.

Do not imagine that mathematics is hard and crabbed, and repulsive to common sense. It is merely the etherealization of common sense.

In science there is only physics; all the rest is stamp collecting.

We only know God in His works, but we are forced by science to admit and to believe with absolute confidence in a Directive Power-in an influence other than physical, or dynamical, or electrical forces.

Vortices of pure energy can exist and, if my theories are right, can compose the bodily form of an intelligent species.