The hypotheses we accept ought to explain phenomena which we have observed. But they ought to do more than this: our hypotheses ought to foretell phenomena which have not yet been observed.

Prudence supposes the value of the end to be assumed, and refers only to the adaptation of the means. It is the relation of right means for given ends.

In art, truth is a means to an end; in science, it is the only end.

Fundamental ideas are not a consequence of experience, but a result of the particular constitution and activity of the mind, which is independent of all experience in its origin, though constantly combined with experience in its exercise.

To discover the laws of operative power in material productions, whether formed by man or brought into being by Nature herself, is the work of a science, and is indeed what we more especially term Science.

The catastrophist constructs theories, the uniformitarian demolishes them.

Astronomy is ... the only progressive Science which the ancient world produced.