I don't need to know everything, I just need to know where to find it, when I need it

Things you can get access to, you should never memorize.

When you examine the lives of the most influential people who have ever walked among us, you discover one thread that winds through them all. They have been aligned first with their spiritual nature and only then with their physical selves.

If you're not sure why you're doing something, you can never do enough of it. Imagination is more important than knowledge.

The relativity principle in connection with the basic Maxwellian equations demands that the mass should be a direct measure of the energy contained in a body; light transfers mass. With radium there should be a noticeable diminution of mass. The idea is amusing and enticing; but whether the Almighty is laughing at it and is leading me up the garden path -- that I cannot know.

I like neither new clothes nor new kinds of food.

Teaching should be such that what is offered is perceived as a valuable gift and not as a hard duty.