The origin of Homo sapiens, as a tiny twig on an improbable branch of a contingent limb on a fortunate tree, lies well below the boundary.

Natural selection is just three factors - over-production, variation, and inheritance combined to produce adaptation to changing local environments. It's not a principle or progress; it's just a principle of local adaptation. You don't make better creatures in any cosmic sense; you make creatures that are better suited to the changing climates of their local habitats.

Life shows no trend to complexity in the usual sense-only an asymmetrical expansion of diversity around a starting point constrained to be simple.

It is the things we think we know - because they are so elementary or because they surround us - that often present the greatest difficulties when we are actually challenged to explain them.

Evolution is a process of constant branching and expansion.

Theory and fact are equally strong and utterly interdependent; one has no meaning without the other. We need theory to organize and interpret facts, even to know what we can or might observe. And we need facts to validate theories and give them substance.

As we discern a fine line between crank and genius, so also (and unfortunately) we must acknowledge an equally graded trajectory from crank to demagogue. When people learn no tools of judgment and merely follow their hopes, the seeds of political manipulation are sown.