Music strikes the ear as a perfectly undisturbed uniform sound which remains unaltered as long as it exists.

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

Just as a physicist has to examine the telescope and galvanometer with which he is working; has to get a clear conception of what he can attain with them, and how they may deceive him; so, too, it seemed to me necessary to investigate likewise the capabilities of our power of thought.

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.

I think the facts leave no doubt that the very mightiest among the chemical forces are of electric origin. The atoms cling to their electric charges, and opposite electric charges cling to each other.

A metaphysical conclusion is either a false conclusion or a concealed experimental conclusion.

Not that I wish by any means to deny, that the mental life of individuals and peoples is also in conformity with law, as is the object of philosophical, philological, historical, moral, and social sciences to establish.