The single most important decision any of us will ever make is whether or not to believe the universe is friendly.

Play is the highest from of research.

In the matter of physics, the first lessons should contain nothing but what is experimental and interesting to see. A pretty experiment is in itself often more valuable than twenty formulae extracted from our minds.

The fear of death is the most unjustified of all fears, for there's no risk of accident for someone who's dead.

The supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a simple datum of experience.

Belief in an external world independent of the perceiving subject is the basis of all natural science.

Non-cooperation in military matters should be an essential moral principle for all true scientists.