Our children long for realistic maps of the future that they can be proud of. Where are the cartographers of human purpose?

Human beings grew up in forests; we have a natural affinity for them. How lovely a tree is, straining toward the sky.

Extinction is the rule. Survival is the exception.

In the way that scepticism is sometimes applied to issues of public concern, there is a tendency to belittle, to condescend, to ignore the fact that, deluded or not, supporters of superstition and pseudoscience are human beings with real feelings, who, like the sceptics, are trying to figure out how the world works and what our role in it might be. Their motives are in many cases consonant with science. If their culture has not given them all the tools they need to pursue this great quest, let us temper our criticism with kindness. None of us comes fully equipped.

When Kepler found his long-cherished belief did not agree with the most precise observation, he accepted the uncomfortable fact. He preferred the hard truth to his dearest illusions, that is the heart of science.

The prediction I can make with the highest confidence is that the most amazing discoveries will be the ones we are not today wise enough to foresee.

For years I've been stressing with regard to UFOs that extraordinary claims require extraordinary evidence.