He who finds a thought that lets us a little deeper into the eternal mystery of nature has been granted great peace.

The thinking it took to get us into this mess is not the same thinking that is going to get us out of it.

It is also a natural thing for a serious young man that he should form for himself as precise an idea as possible of the goal of his desires.

I do not believe in the God of theology who rewards good and punishes evil.

I believe that a simple and unassuming manner of life is best for everyone, best both for the body and the mind.

I think that only daring speculation can lead us further and not accumulation of facts.

For scientific endeavor is a natural whole the parts of which mutually support one another in a way which, to be sure, no one can anticipate.