You can't solve problems with the same thinking that caused them.
Experience is knowledge. All the rest is information.
Be kind to people who are different from you.
Isn't it strange that I who have written only unpopular books should be such a popular fellow?
No one must think that Newton’s great creation can be overthrown in any real sense by this [Theory of Relativity] or by any other theory. His clear and wide ideas will for ever retain their significance as the foundation on which our modern conceptions of physics have been built.
Every age has its beautiful moments.