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

It is more important to have beauty in one’s equation than to have them fit experiment

The underlying physical laws necessary for the mathematical theory of a larger part of physics and the whole of chemistry are thus completely known.

Well, in the first place, it leads to great anxiety as to whether it's going to be correct or not ... I expect that's the dominating feeling. It gets to be rather a fever... At age 60, when asked about his feelings on discovering the Dirac equation.

I admired Bohr very much. We had long talks together, long talks in which Bohr did practically all the talking.

As time goes on, it becomes increasingly evident that the rules which the mathematician finds interesting are the same as those which Nature has chosen.

I think it is a peculiarity of myself that I like to play about with equations, just looking for beautiful mathematical relations which maybe don't have any physical meaning at all. Sometimes they do. At age 60.

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

When [Erwin Schrödinger] went to the Solvay conferences in Brussels, he would walk from the station to the hotel where the delegates stayed, carrying all his luggage in a rucksack and looking so like a tramp that it needed a great deal of argument at the reception desk before he could claim a room.