It’s a poor atom blaster that won’t point both ways.

Old people think young people haven't learned about love. Young people think old people have forgotten about love.

There is nothing so eternally adhesive as the memory of power.

Early in my school career, I turned out to be an incorrigible disciplinary problem. I could understand what the teacher was saying as fast as she could say it, I found time hanging heavy, so I would occasionally talk to my neighbor. That was my great crime, I talked in school.

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.

Intelligence is an extremely subtle concept. It's a kind of understanding that flourishes if it's combined with a good memory, but exists anyway even in the absence of good memory. It's the ability to draw consequences from causes, to make correct inferences, to foresee what might be the result, to work out logical problems, to be reasonable, rational, to have the ability to understand the solution from perhaps insufficient information. You know when a person is intelligent, but you can be easily fooled if you are not yourself intelligent.

The further a device is removed from human control, the more authentically mechanical it seems, and the whole trend in technology has been to devise machines that are less and less under direct human control and more and more under their own apparent will.