“Like the soil, mind is fertilized while it lies fallow, until a new burst of bloom ensues.”

“Every great advance in science has issued from a new audacity of imagination. ”

“Scientific principles and laws do not lie on the surface of nature. They are hidden, and must be wrested from nature by an active and elaborate technique of inquiry. ”

“The only freedom that is of enduring importance is the freedom of intelligence, that is to say, freedom of observation and of judgment, exercised in behalf of purposes that are intrinsically worth while. The commonest mistake made about freedom is, I think, to identify it with freedom of movement, or, with the external or physical side of activity.”

“Men have gone on to build up vast intellectual schemes, philosophies, and theologies, to prove that ideals are not real as ideals but as antecedently existing actualities. They have failed to see that in converting moral realities into matters of intellectual assent they have evinced lack of moral faith. Faith that something should be in existence as far as lies in our power is changed into the intellectual belief that it is already in existence. When physical existence does not bear out the assertion, the physical is subtly changed into the metaphysical. In this way, moral faith has been inextricably tied up with intellectual beliefs about the supernatural.”

“Forty years spent in wandering in a wilderness like that of the present is not a sad fate--unless one attempts to make himself believe that the wilderness is after all itself the promised land”

“Conflict is the gadfly of thought. It stirs us to observation and memory. It instigates invention. It shocks us out of sheep-like passivity, and sets us at noting and contriving…conflict is a sine qua non of reflection and ingenuity.”