The theoretical idea ... does not arise apart from and independent of experience; nor can it be derived from experience by a purely logical procedure. It is produced by a creative act. Once a theoretical idea has been acquired, one does well to hold fast to it until it leads to an untenable conclusion.

Pure mathematics is, in its way, the poetry of logical ideas. ... [By seeking] logical beauty spiritual formulas are discovered necessary for the deeper penetration into the laws of nature.

Out yonder there was this huge world...which stands before us like a great eternal riddle.

Unless the cause of peace based on law gathers behind it the force and zeal of a religion, it hardly can hope to succeed.

The greatest scientists are artists as well.

Intuitive powers played a central role in my scientific work, not wild speculation, yet a valued resource when no other approach was available.

I am not more gifted than anybody else. I am just more curious than the average person and I will not give up a problem until I have found the proper solution.