Intelligence is an accident of evolution, and not necessarily an advantage.

The great secret of the successful fool is that he's no fool at all

[A]ll knowledge is one. When a light brightens and illuminates a corner of a room, it adds to the general illumination of the entire room. Over and over again, scientific discoveries have provided answers to problems that had no apparent connection with the phenomena that gave rise to the discovery.

I even got a letter from a young woman in British Columbia that began as follows: 'Today I am eighteen. I am sitting at the window, looking out at the rain, and thinking how much I love you.'

There are so many benefits to be derived from space exploration and exploitation; why not take what seems to me the only chance of escaping what is otherwise the sure destruction of all that humanity has struggled to achieve for 50,000 years?

There is no belief, however foolish, that will not gather its faithful adherents who will defend it to the death.

I have never written a book that didn't teach me far more than it taught my reader.