Knowledge keeps no better than fish.

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.

In every age of well-marked transition, there is the pattern of habitual dumb practice and emotion which is passing and there is oncoming a new complex of habit.

It is more important that a proposition be interesting than that it be true.

In order to acquire learning, we must first shake ourselves free of it.

There is no greater hindrance to the progress of thought than an attitude of irritated party-spirit.