Indeed the reasoned criticism of a prevailing belief is a service to the proponents of that belief; if they are incapable of defending it, they are well advised to abandon it. This self-questioning and error-correcting aspect of the scientific method is its most striking property.

Virtually every major technological advance in the history of the human species - back to the invention of stone tools and the domestication of fire - has been ethically ambiguous.

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.

The Earth is a place. It is by no means the only place. It is not even a typical place.

We live on a hunk of rock and metal that circles a humdrum star that is one of 400 billion other stars that make up the Milky Way Galaxy which is one of billions of other galaxies which make up a universe which may be one of a very large number, perhaps an infinite number, of other universes. That is a perspective on human life and our culture that is well worth pondering.

The total number of stars in the Universe is larger than all the grains of sand on all the beaches of the planet Earth.

The uniqueness of humans has been claimed on many grounds, but most often because of our tool-making, culture, language, reason and morality. We have them, the other animals don't, and -- so the argument goes -- that's that.