...the only simplicity to be trusted is the simplicity to be found on the far side of complexity.

The 'silly question' is the first intimation of some totally novel development.

To see what is general in what is particular, and what is permanent in what is transitory, is the aim of scientific thought.

But you can catch yourself entertaining habitually certain ideas and setting others aside; and that, I think, is where our personal destinies are largely decided.

There is no more common error than to assume that, because prolonged and accurate mathematical calculations have been made, the application of the result to some fact of nature is absolutely certain.

It takes an extraordinary intelligence to contemplate the obvious.

Ideas won't keep. Something must be done about them.