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

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.

Let nobody be afraid of true freedom of thought. Let us be free in thought and criticism; but, with freedom, we are bound to come to the conclusion that science is not antagonistic to religion, but a help to it.

I believe that the more thoroughly science is studied, the further does it take us from anything comparable to atheism.

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

There is nothing new to be discovered in physics now. All that remains is more and more precise measurement.

Large increases in cost with questionable increases in performance can be tolerated only in race horses and fancy women.