All means prove but blunt instruments, if they have not behind them a living spirit.

If we have the courage to decide ourselves for peace we will have peace.

They come into being not through demonstration but through revelation, through the medium of powerful personalities.

Imagination is more valuable than information.

There comes a time when the mind takes a higher plane of knowledge but can never prove how it got there.

... on principle, it is quite wrong to try founding a theory on observable magnitudes alone. In reality the very opposite happens. It is the theory which decides what we can observe.

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