If we offer too much silent assent about mysticism and superstition - even when it seems to be doing a little good - we abet a general climate in which scepticism is considered impolite, science tiresome, and rigorous thinking somehow stuffy and inappropriate.

The reappearance of the crescent moon after the new moon; the return of the Sun after a total eclipse, the rising of the Sun in the morning after its troublesome absence at night were noted by people around the world; these phenomena spoke to our ancestors of the possibility of surviving death. Up there in the skies was also a metaphor of immortality.

We are the universe experiencing itself.

The surface of the Earth is the shore of the cosmic ocean. From it we have learned most of what we know. Recently, we have waded a little out to sea, enough to dampen our toes or, at most, wet our ankles. The water seems inviting. The ocean calls.

We have begun to contemplate our origins: starstuff pondering the stars; organized assemblages of ten billion billion billion atoms considering the evolution of atoms; tracing the long journey by which, here at least, consciousness arose.

Science is a way of thinking that helps you not to fool yourself.

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