To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advance in science.

If you are out to describe the truth, leave elegance to the tailor.

A theory is the more impressive the greater the simplicity of its premises, the more different things it relates, and the more extended its area of applicability.

I never made one of my discoveries through the process of rational thinking.

It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience.

Reality is merely an illusion, albeit a very persistent one.