It is impossible to solve significant problems using the same knowledge that created them.

The theoretical idea ... does not arise apart from and independent of experience; nor can it be derived from experience by a purely logical procedure. It is produced by a creative act. Once a theoretical idea has been acquired, one does well to hold fast to it until it leads to an untenable conclusion.

A ship is always safe at the shore - but that is NOT what it is built for.

Time is relative; its only worth depends upon what we do as it is passing.

When we first got married, we made a pact. It was this: In our life together, it was decided I would make all of the big decisions and my wife would make all of the little decisions. For fifty years, we have held true to that agreement. I believe that is the reason for the success in our marriage. However, the strange thing is that in fifty years, there hasn’t been one big decision.

We are in the position of a little child entering a huge library, whose walls are covered to the ceiling with books in many different languages. The child knows that someone must have written those books. It does not know who or how. It does not understand the the languages in which they are written. The child notes a definite plan in the arrangement of the books, a mysterious order, which it does not comprehend but only dimly suspects.

One may say the eternal mystery of the world is its comprehensibility.