You can prove anything you want by coldly logical reason---if you pick the proper postulates.

Married life had taught Toran the futility of arguing with a female in a dark-brown mood.

It's humbling to think that all animals, including human beings, are parasites of the plant world.

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.

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.

I received the fundamentals of my education in school, but that was not enough. My real education, the superstructure, the details, the true architecture, I got out of the public library.

Any planet is 'Earth' to those that live on it.