Perhaps the depth of love can be calibrated by the number of different selves that are actively involved in a given relationship.

You mean am I for it or against it? You think this is a key question I'm going to be asked on Vega, and you want to make sure I give the right answer? Okay. Overpopulation is why I'm in favor of homosexuality and a celibate clergy. A celibate clergy is an especially good idea, because it tends to suppress any hereditary propensity toward fanaticism.

Centuries hence, when current social and political problems may seem as remote as the problems of the Thirty Years' War are to us, our age may be remembered chiefly for one fact: It was the time when the inhabitants of the earth first made contact with the vast cosmos in which their small planet is embedded.

[Kepler] preferred the hard truth to his dearest illusions, and that is the heart of science.

I believe that the extraordinary should be pursued. But extraordinary claims require extraordinary evidence.

Our planet is a lonely speck in the great enveloping cosmic dark. In our obscurity, in all this vastness, there is no hint that help will come from elsewhere to save us from ourselves.

In the middle 1970s an astronomer I admire put together a modest manifesto called "Objections to Astrology" and asked me to endorse it. I struggled with his wording, and in the end found myself unable to sign, not because I thought astrology has any validity whatever, but because I felt (and still feel) that the tone of the statement was authoritarian.