A single message from space will show that it is possible to live through technological adolescence. . . . It is possible that the future of human civilization depends on the receipt of interstellar messages.

Except in pure mathematics, nothing is known for certain (although much is certainly false).

The illegality of cannabis is outrageous.

I worry that, especially as the Millennium edges nearer, pseudo-science and superstition will seem year by year more tempting, the siren song of unreason more sonorous and attractive.

That we can now think of no mechanism for astrology is relevant but unconvincing. No mechanism was known, for example, for continental drift when it was proposed by Wegener. Nevertheless, we see that Wegener was right, and those who objected on the grounds of unavailable mechanism were wrong.

If we continue to accumulate only power and not wisdom, we will surely destroy ourselves.

We are the first species to have taken our evolution into our own hands.