Depression is rage spread thin.

Progress, far from consisting in change, depends on retentiveness. When change is absolute there remains no being to improve and no direction is set for possible improvement: and when experience is not retained, as among savages, infancy is perpetual. Those who cannot remember the past are condemned to repeat it.

Proofs are the last thing looked for by a truly religious mind which feels the imaginative fitness of its faith.

Repetition is the only form of permanence that Nature can achieve.

Sanity is a madness put to good uses.

Science is nothing but developed perception, interpreted intent, common sense rounded out, and minutely articulated.

Science, then, is the attentive consideration of common experience; it is common knowledge extended and refined. Its validity is of the same order as that of ordinary perception; memory, and understanding. Its test is found, like theirs, in actual intuition, which sometimes consists in perception and sometimes in intent. The flight of science is merely longer from perception to perception, and its deduction more accurate of meaning from meaning and purpose from purpose. It generates in the mind, for each vulgar observation, a whole brood of suggestions, hypotheses, and inferences. The sciences bestow, as is right and fitting, infinite pains upon that experience which in their absence would drift by unchallenged or misunderstood. They take note, infer, and prophesy. They compare prophesy with event, and altogether they supply—so intent are they on reality—every imaginable background and extension for the present dream.

The empiricist ... thinks he believes only what he sees, but he is much better at believing than at seeing.

The mathematician can afford to leave to his clients, the engineers, or perhaps the popular philosophers, the emotion of belief: for himself he keeps the lyrical pleasure of metre and of evolving equations: and it is a pleasant surprise to him and an added problem if he finds that the arts can use his calculations, or that the senses can verify them, much as if a composer found that sailors could heave better when singing his songs.

The scientific value of truth is not, however, ultimate or absolute. It rests partly on practical, partly on aesthetic interests. As our ideas are gradually brought into conformity with the facts by the painful process of selection,—for intuition runs equally into truth and into error, and can settle nothing if not controlled by experience,—we gain vastly in our command over our environment. This is the fundamental value of natural science

The tide of evolution carries everything before it, thoughts no less than bodies, and persons no less than nations.

Theory helps us to bear our ignorance of fact.

To most people, I fancy, the stars are beautiful; but if you asked why, they would be at a loss to reply, until they remembered what they had heard about astronomy, and the great size and distance and possible habitation of those orbs. ... [We] persuade ourselves that the power of the starry heavens lies in the suggestion of astronomical facts.

What is false in the science of facts may be true in the science of values.

When all beliefs are challenged together, the just and necessary ones have a chance to step forward and to re-establish themselves alone.

Whoever it was who searched the heavens with a telescope and found no God would not have found the human mind if he had searched the brain with a microscope.