(My) transcript of K.C.Cole’s latest perspective:

How do we know what we know? In science, that’s always a central question, which is why it surprises me that there isn’t more of “how do we know?” in the so called debate over evolution. Human evolution is pretty disturbing, of course; embarrasing parents are hard enough to deal with — who wants fish, fungi, and slime-molds stinking up the family tree. It doesn’t help that our whole existence seems to be an accident — the end result of a long chain of small changes, brought about purely by chance. Stray cosmic rays tweaking the DNA of ancient critters, in ways that made them better at hiding, or eating, or getting about, and therefore having more offspring. This process even produced the big brains and loud mouths that let us argue -incessantly, it seems- over how it all came to be. “A likely story,” some of you were saying, how do I know it’s true? In the same way I know, the person sitting next to me on the bus isn’t a giant banana — not just because he doesn’t look like a banana, but because he doesn’t smell like a banana, or sound like a banana, or act like a banana; and no one else on the bus thinks he’s a banana either. In other words, I have multiple lines of evidence, and all of them agree. The other people on the bus are conducting the same experiment, and they agree too. It’s the same reason I believe an even more unlikely creation saga, the big bang; no one was around to see the universe explode into being some 13 billion years ago, yet the theory is widely accepted, because so many different lines of evidence clearly point in the same direction; the shape of the universe, the motions of the galaxies, the composition of matter. And so it is with evolution: it’s not just the story of ever-increasing complexity written in the fossil record; it’s the way wings and eyes have evolved in different places, over and over again; the way devevloping embryos of rabbits and humans look virtually the same; we grow tails and gill-slits for heaven’sakes; the way our genes match-up; more than 99% the same with chimps, 50% with fungi; we even see evolution in action right infront of our noses, if we didn’t , we wouldn’t be worried about drug-resistant strains of bacteria, not to mention bird-flu. That’s why even the most devoutly religious scientist takes evolution on evidence, not on faith. Ignoring evidence can get you into trouble; you just might find yoruself sitting on the bus, someday, chatting up a banana.