As our own species is in the process of proving, one cannot have superior science and inferior morals. The combination is unstable and self-destroying.

The entire sweep of human history from the dark ages into the unknown future was considerably less important at the moment than the question of a certain girl and her feelings toward him.

He found it both sad and fascinating that only through an artificial universe of video images could she establish contact with the real world.

Excessive interest in pathological behavior was itself pathological

I am an optimist. Anyone interested in the future has to be otherwise he would simply shoot himself.

Attempting to define science fiction is an undertaking almost as difficult, though not so popular, as trying to define pornography... In both pornography and SF, the problem lies in knowing exactly where to draw the line.

At the present rate of progress, it is almost impossible to imagine any technical feat that cannot be achieved - if it can be achieved at all - within the next few hundred years.