Isolated facts and experiments have in themselves no value, however great their number may be. They only become valuable in a theoretical or practical point of view when they make us acquainted with the law of a series of uniformly recurring phenomena, or, it may be, only give a negative result showing an incompleteness in our knowledge of such a law, till then held to be perfect.

The originator of a new concept...finds, as a rule, that it is much more difficult to find out why other people do not understand him, than it was to discover the new truth.

The total quantity of all the forces capable of work in the whole universe remains eternal and unchanged throughout all their changes. All change in nature amounts to this, that force can change its form and locality, without its quantity being changed. The universe possesses, once for all, a store of force which is not altered by any change of phenomena, can neither be increased nor diminished, and which maintains any change which takes place on it.

I then endeavoured to show that it is more especially in the thorough conformity with law which natural phenomena and natural products exhibit, and in the comparative ease with which laws can be stated, that this difference exists.

Black is real sensation, even if it is produced by entire absence of light. The sensation of black is distinctly different from the lack of all sensations.

Whoever, in the pursuit of science, seeks after immediate practical utility, may generally rest assured that he will seek in vain.

What we see is the solution to a computational problem, our brains compute the most likely causes from the photon absorptions within our eyes.