"The only laws of matter are those which our minds must fabricate, and the only laws of mind are fabricated for it by matter."

"I saw a rat today in the college garden, and I thought how much more pleasant it would be to be a rat than a professor."

"I have also a paper afloat, with an electromagnetic theory of light, which, till I am convinced to the contrary, I hold to be great guns."

"The human mind is seldom satisfied, and is certainly never exercising its highest functions, when it is doing the work of a calculating machine."

"It is a perfect pleasure to think of anything that is not connected with the examination."