If we can't express what we know in the form of numbers, we really don't know much about it.

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

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

Science is bound, by the everlasting vow of honour, to face fearlessly every problem which can be fairly presented to it.

I have not had a moment's peace or happiness in respect to electromagnetic theory since November 28, 1846. All this time I have been liable to fits of ether dipsomania, kept away at intervals only by rigorous abstention from thought on the subject.

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

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 modern physics.