The claim is also sometimes made that science is as arbitrary or irrational as all other claims to knowledge, or that reason itself is an illusion. As Ethan Allen said Those who invalidate reason ought seriously to consider whether they argue against reason with or without reason; if with reason, then they establish the principle that they are labouring to dethrone. If they argue without reason, which they must do, in order to be consistent with themselves, they are out of reach of rational conviction, nor do they deserve a rational argument.

We can't help it. Life looks for life.

I would be very ashamed of my civilization if we did not try to find out if there is life in outer space.

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

The prediction of nuclear winter is drawn not, of course, from any direct experience with the consequences of global nuclear war, but rather from an investigation of the governing physics.

Science is more than a body of knowledge. It's a way of thinking: a way of skeptically interrogating the universe.

The hole in the ozone layer is a kind of skywriting. At first it seemed to spell out our continuing complacency before a witch's brew of deadly perils. But perhaps it really tells of a newfound talent to work together to protect the global environment.