A new position of responsibility will usually show a man to be a far stronger creature than was supposed.

Once you accept an idea, it's an idea whose time has come.

The mind of your own enemy, the pupil, is working away from you, as keenly and eagerly as is the mind of the commander on the other side from the scientific general. Just what the respective enemies want and think, and what they know or do not know, are as hard things for the teachers as for the general to find out.

Much of what we call evil is due entirely to the way men take the phenomenon. It can so often be converted into a bracing and tonic good by a simple change of the sufferer's inner attitude from one of fear to one of fight; its string can so often depart and turn into a relish when, after vainly seeking to shun it, we agree to face about and bear it.

Life shall be built in doing and suffering and creating.

Theory must mediate between all previous truths and certain new experiences

Experience, as we know, has a way of boiling over, and making us correct our present formulas.