One thought that occurs to me is that men will continue to withdraw from nature in order to create an environment that will suit them better.

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

Unfortunately, in many cases, people who write science fiction violate the laws of nature, not because they want to make a point, but because they don't know what the laws of nature are.

The energy requirements for interstellar travel are so great that it is inconceivable to me that any creatures piloting their ships across the vast depths of space would do so only in order to play games with us over a period of decades. If they want to make contact, they would make contact; if not, they would save their energy and go elsewhere.

It was obvious that bigotry was never a one-way operation, that hatred bred hatred!

Experimentation is the least arrogant method of gaining knowledge. The experimenter humbly asks a question of nature.

Once, when a religionist denounced me in unmeasured terms, I sent him a card saying, "I am sure you believe that I will go to hell when I die, and that once there I will suffer all the pains and tortures the sadistic ingenuity of your deity can devise and that this torture will continue forever. Isn't that enough for you? Do you have to call me bad names in addition?"