Except in pure mathematics, nothing is known for certain (although much is certainly false).

At the heart of science is an essential balance between two seemingly contradictory attitudes-an openness to new ideas, no matter how bizarre or counterintuitive they may be, and the most ruthless skeptical scrutiny of all ideas, old and new. This is how deep truths are winnowed from deep nonsense.

Accommodation to change, the thoughtful pursuit of alternative futures are keys to the survival of civilization and perhaps of the human species.

When we look up at night and view the stars, everything we see is shinning because of distant nuclear fusion.

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.

Science is a way of thinking much more than it is a body of knowledge. Its goal is to find out how the world works, to seek what regularities there may be, to penetrate to the connections of things-from subatomic particles, which may be the constituents of all matter, to living organisms, the human social community, and thence to the cosmos as a whole.

The idea that God is an oversized white male with a flowing beard, who sits in the sky and tallies the fall of every sparrow is ludicrous. But if by 'God,' one means the set of physical laws that govern the universe, then clearly there is such a God. This God is emotionally unsatisfying... it does not make much sense to pray to the law of gravity.