People talk about human intelligence as the greatest adaptation in the history of the planet. It is an amazing and marvelous thing, but in evolutionary terms, it is as likely to do us in as to help us along.

You put three facts together - that all organisms produce more offspring that can survive, that there's variation among organisms, and that at least some of that variation is inherited - and the syllogistic inference is natural selection.

No Geologist worth anything is permanently bound to a desk or laboratory, but the charming notion that true science can only be based on unbiased observation of nature in the raw is mythology. Creative work, in geology and anywhere else, is interaction and synthesis: half-baked ideas from a bar room, rocks in the field, chains of thought from lonely walks, numbers squeezed from rocks in a laboratory, numbers from a calculator riveted to a desk, fancy equipment usually malfunctioning on expensive ships, cheap equipment in the human cranium, arguments before a road cut.

Science can't tell us what our life means ethically. It can't tell us what we are meant to do as moral creatures. But, insofar as science can understand what we're made of, and what we're related to, the Darwinian revolution completely revised our ideas about who we are and what we're related to and how long we've been here and why we're on this Earth.

I can envision observations and experiments that would disprove any evolutionary theory I know.

Organisms are not billiard balls, propelled by simple and measurable external forces to predictable new positions on life's pool table. Sufficiently complex systems have greater richness. Organisms have a history that constrains their future in myriad, subtle ways.

Skepticism's bad rap arises from the impression that, however necessary the activity, it can only be regarded as a negative removal of false claims. Not so... Proper debunking is done in the interest of an alternate model of explanation, not as a nihilistic exercise. The alternate model is rationality itself, tied to moral decency--the most powerful joint instrument for good that our planet has ever known.