How was I able to live alone before, my little everything? Without you I lack self-confidence, passion for work, and enjoyment of life--in short, without you, my life is no life. [Written to his wife, Mileva]

As far as the laws of mathematics refer to reality, they are not certain, and as far as they are certain, they do not refer to reality.

The ordinary adult never gives a thought to space-time problems ... I, on the contrary, developed so slowly that I did not begin to wonder about space and time until I was an adult. I then delved more deeply into the problem than any other adult or child would have done.

The most beautiful thing we can experience is the mysterious. It is the source of all true art and science.

The only thing more dangerous than ignorance is arrogance

My pacifism is not based on any intellectual theory but on a deep antipathy to every form of cruelty and hatred.

I do not believe in the God of theology who rewards good and punishes evil. My God created laws that take care of that. His universe is not ruled by wishful thinking, but by immutable laws.