Scientific discovery and scientific knowledge have been achieved only by those who have gone in pursuit of it without any practical purpose whatsoever in view.

There is a real world independent of our senses; the laws of nature were not invented by man, but forced on him by the natural world. They are the expression of a natural world order.

Experiment is the only means of knowledge at our disposal. Everything else is poetry, imagination.

Insight must precede application.

It is not the possession of truth, but the success which attends the seeking after it, that enriches the seeker and brings happiness to him.

An important scientific innovation rarely makes its way by gradually winning over and converting its opponents: What does happen is that the opponents gradually die out.

We have no right to assume that any physical laws exist, or if they have existed up until now, that they will continue to exist in a similar manner in the future.