Since ancient times, the philosophers' secret has always been this: we know that God does not exist, or, at least, if he does, he's utterly indifferent to our individual affairs--but we can't let the rabble know that; it's the fear of God, the threat of divine punishment and the promise of divine reward, that keeps in line those too unsophisticated to work out questions of morality on their own.

If theft is advantageous to everyone who succeeds at it, and adultery is a good strategy, at least for males, for increasing presence in the gene pool, why do we feel they are wrong? Shouldn't the only morality that evolution produces be the kind Bill Clinton had - being sorry you got caught?

A science fiction writer should try to combine the intimately human with the grandly cosmic.

You can't choose the ways in which you'll be tested.

That natural selection can produce changes within a type is disputed by no one, not even the staunchest creationist. But that it can transform one species into another — that, in fact, has never been observed.

How do you define God? Like this. A God I could understand, at least potentially, was infinitely more interesting and relevant than one that defied comprehension.

Paul Levinson has outdone himself: The Plot to Save Socrates is a philosophically rich gem full of big ideas and wonderful time-travel tricks.