Theoretical physicists accept the need for mathematical beauty as an act of faith... For example, the main reason why the theory of relativity is so universally accepted is its mathematical beauty.

The measure of greatness in a scientific idea is the extent to which it stimulates thought and opens up new lines of research.

A great deal of my work is just playing with equations and seeing what they give.

It was not until some weeks later that I realized there is no need to restrict oneself to 2 by 2 matrices. One could go on to 4 by 4 matrices, and the problem is then easily soluable. In retrospect, it seems strange that one can be so much held up over such an elementary point. The resulting wave equation for the electron turned out to be very successful. It led to correct values for the spin and the magnetic moment. This was quite unexpected. The work all followed from a study of pretty mathematics, without any thought being given to these physical properties of the electron.

Living is worthwhile if one can contribute in some small way to this endless chain of progress.

I consider that I understand an equation when I can predict the properties of its solutions, without actually solving it.

If we are honest - and scientists have to be - we must admit that religion is a jumble of false assertions, with no basis in reality.