William Whewell

It is a test of true theories not only to account for but to predict phenomena.

Hence no force, however great, can stretch a cord, however fine, into a horizontal line which is accurately straight there will always be a bending downwards.

Every failure is a step to success.

Our assent to the hypothesis implies that it is held to be true of all particular instances. That these cases belong to past or to future times, that they have or have not already occurred, makes no difference in the applicability of the rule to them. Because the rule prevails, it includes all cases.

We cannot observe external things without some degree of Thought nor can we reflect upon our Thoughts, without being influenced in the course of our reflection by the Things which we have observed.

Man is the interpreter of nature, science the right interpretation.

The system becomes more coherent as it is further extended. The elements which we require for explaining a new class of facts are already contained in our system. . . . In false theories, the contrary is the case.

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.

And so no force, however great, Can stretch a cord, however fine, Into a horizontal line That shall be absolutely straight. Quoted as an example of accidental metre and rhyme.

Nobody since Newton has been able to use geometrical methods to the same extent for the like purposes and as we read the Principia we feel as when we are in an ancient armoury where the weapons are of gigantic size and as we look at them we marvel what manner of man he was who could use as a weapon what we can scarcely lift as a burden.

There is a mask of theory over the whole face of nature.