“Insofar as he makes use of his healthy senses, man himself is the best and most exact scientific instrument possible. The greatest misfortune of modern physics is that its experiments have been set apart from man, as it were, physics refuses to recognize nature in anything not shown by artificial instruments, and even uses this as a measure of its accomplishments.”

“The greatest evil that can befall man is that he should come to think ill of himself.”

“The suffering may be moral or physical; and in my opinion it is just as absurd to call a man a coward who destroys himself, as to call a man a coward who dies of a malignant fever.”

“Weakness' is weakness only in light of the aims man sets for himself, the instruments at his disposal and the laws he imposes.”

“When we treat man as he is we make him worse than he is. When we treat him as if he already was what he potentially could be We make him what he should be.”

“Pipes are not to be used for teaching, nor any artificial instruments, as the harp, or the like: but whatsoever will make the hearers good men.”

“All truly wise thoughts have been thought already thousands of times; but to make them truly ours, we must think them over again honestly, until they take root in our personal experience.”