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

A theory is the more impressive the greater the simplicity of its premises is, the more different kinds of things it relates, and the more extended is its area of applicability. Therefore the deep impression which classical thermodynamics made upon me. It is the only physical theory of universal content concerning which I am convinced that within the framework of the applicability of its basic concepts, it will never be overthrown.

The woman who follows the crowd will usually go no further than the crowd. The woman who walks alone is likely to find herself in places no one has ever been before.

A theory is the more impressive the greater the simplicity of its premises is, the more different kinds of things it relates, and the more extended its area of applicability.

We still do not know one thousandth of one percent of what nature has revealed to us.

The content of scientific theory itself offers no moral foundation for the personal conduct of life.

It is the same with people as it is with riding a bike. Only when moving can one comfortably maintain one's balance.