The essential building block is...the true love that is impossible to define for those who have never experienced it and unnecessary to define for those who have.

The dangers that face the world can, every one of them, be traced back to science. The salvations that may save the world will, every one of them, be traced back to science.

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?

No sensible decision can be made any longer without taking into account not only the world as it is, but the world as it will be.

There’s nothing to it. All you have to do is take a close look at yourself and you will understand everyone else. We’re in no way different ourselves... You show me someone who can’t understand people and I’ll show you someone who has built up a false image of himself.

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 accident of evolution, and not necessarily an advantage.