I think if we ever reach the point where we think we thoroughly understand who we are and where we came from, we will have failed.

Science is much more than a body of knowledge. It is a way of thinking. This is central to its success. Science invites us to let the facts in, even when they don't conform to our preconceptions. It counsels us to carry alternative hypotheses in our heads and see which ones best match the facts. It urges on us a fine balance between no-holds-barred openness to new ideas, however heretical, and the most rigorous skeptical scrutiny of everything - new ideas and established wisdom.

Our loyalties are to the species and the planet. We speak for Earth. Our obligation to survive is owed not just to ourselves but also to that Cosmos, ancient and vast, from which we spring.

Some 5 billion years from now, there will be a last perfect day on Earth... then the sun will begin to die, life will be extinguished, the oceans will boil and evaporate away.

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

The chief deficiency I see in the skeptical movement is its polarization: Us vs. Them - the sense that we have a monopoly on the truth; that those other people who believe in all these stupid doctrines are morons; that if you're sensible, you'll listen to us; and if not, to hell with you. This is nonconstructive. It does not get our message across. It condemns us to permanent minority status.

At the extremes it is difficult to distinguish pseudoscience from rigid, doctrinaire religion.