He who refuses to embrace a unique opportunity loses the prize as surely as if he had failed.

...These healers...my intellect has been unable to assimilate their theories....But their facts are patent and startling; and anything that interferes with the multiplication of such facts, and with our freest opportunity of observing and studying them, will, I believe, be a public calamity.

Social evolution is a resultant of the interaction of two wholly distinct factors: the individual ... bearing all the power of initiative and origination in his hands; and, second, the social environment with its power of adopting or rejecting both him and his gifts. Both factors are essential to change. The community stagnates without the impulse of the individual. The impulse dies away without the sympathy of the community.

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 originally studied medicine in order to be a physiologist, but I drifted into psychology and philosophy from a sort of fatality. I never had any philosophic instruction, the first lecture on psychology I ever heard being the first I ever gave.

Men habitually use only a small part of the power which they actually possess.

If you only care enough for a result, you will almost certainly attain it. Only you must, then, really wish these things, and wish them exclusively, and not wish at the same time a hundred other incompatible things just as strongly.