There are two primary choices in life: to accept conditions as they exist, or accept the responsibility for changing them.

Life would be tragic if it weren't funny.

The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge.

You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete.

Intelligence without ambition is a bird without wings.

Everyone thinks of changing the world, but no one thinks of changing himself.

My goal is simple. It is a complete understanding of the universe, why it is as it is and why it exists at all.

No matter what people tell you, words and ideas can change the world.

We should seek the greatest value of our action.