All our life, so far as it has definite form, is but a mass of habits.

If an unusual necessity forces us onward, a surprising thing occurs. The fatigue gets worse up to a certain point, when, gradually or suddenly, it passes away and we are fresher than before!

What holds attention determines action.

Faith means belief in something concerning which doubt is theoretically possible.

... if we take the universe of 'fitting,' countless coats 'fit' backs, and countless boots 'fit' feet, on which they are not practically fitted; countless stones 'fit' gaps in walls into which no one seeks to fit them actually. In the same way countless opinions 'fit' realities, and countless truths are valid, tho no thinker ever thinks them.

Whatever universe a professor believes in must at any rate be a universe that lends itself to lengthy discourse. A universe definable in two sentences is something for which the professorial intellect has no use. No faith in anything of that cheap kind!

I believe there is no source of deception in the investigation of nature which can compare with a fixed belief that certain kinds of phenomena are IMPOSSIBLE.