Seek simplicity but distrust it.

Almost all new ideas have a certain aspect of foolishness when they are first produced.

Inventive genius requires pleasurable mental activity as a condition for its vigorous exercise

All practical teachers know that education is a patient process of mastery of details, minute by minute, hour by hour, day by day.

There is no more common error than to assume that, because prolonged and accurate mathematical calculations have been made, the application of the result to some fact of nature is absolutely certain.

A science which hesitates to forget its founders is lost.

...the self-satisfied dogmatism with which mankind at each period of its history cherishes the delusion of the finality of existing modes of knowledge.