Lenski and common descent

Ender · Post by **Ender** » 2008-06-22 11:24pm

In discussing Lenski's e.coli experiment the assertion was made that this does not prove common origin. I responded that yes, it did. Counter argument is

Um, methinks your understanding of the concept of proof is a little flawed. More evidence? Sure closer to proof, sure. Proof? no. It's not really something that can ever be proved so much that lim x->0 != 0.

Suggestions?

Post by **Alyrium Denryle** » 2008-06-23 01:15am

Just point out endogenous retroviruses, the existence of Hox genes, molecular clock divergence times cross referenced against the fossil record etc etc etc.

Common descent is one of those little things that is hard to get around.

Oh, and did I mention Mitochondria? Those just so happen to have used to have been endosymbionts. Is he suggesting this happened multiple times?

Napoleon the Clown · Post by **Napoleon the Clown** » 2008-06-23 01:40am

He's being an semantics arguing twat, essentially. What he appears to be saying is that it isn't absolute total proof, that it doesn't demonstrate common origin to be the only explanation. From that angle, yeah, he's right. But science rarely comes out with stuff like that. It's semantics, and he's using an unnecessarily narrow definition of "proof".

Post by **Surlethe** » 2008-06-23 03:58pm

Fallacy of equivocation: he's using the mathematical definition of "proof" instead of the colloquial definition.

Post by **Alyrium Denryle** » 2008-06-23 05:12pm

Surlethe wrote:Fallacy of equivocation: he's using the mathematical definition of "proof" instead of the colloquial definition.

There is that. There is also the little bit where science does not prove anything. He is fundamentally misunderstanding how science works. We falsify, not prove, models.

Post by **Darth Wong** » 2008-06-23 09:09pm

Try this:

When you pick up a smooth pebble from a river bed, you can declare that it was rounded and smoothed by the action of water eroding its surface. But here's the rub: you cannot prove this statement. You have no history of this particular pebble; you don't know where it was 5 days ago, never mind where it was 5 years ago or what it looked like at the time. And yet, no one in his right mind would contest the statement.

Why? Because an explanation is not the same thing as a proof of history, and it doesn't need to be. In order to explain a mystery, you need only present a plausible mechanism, ie- something which could have caused it. You don't need to prove it. And if there is only one plausible mechanism, then you can state it with confidence. Like erosion smoothing the pebble in the riverbed.

Every time creationists ask for "proof" of evolutionary history, that's what they are doing: they are taking a situation where a plausible mechanism should be enough, and demanding proof that it happened that way. It's just as absurd as demanding proof in the riverbed pebble example.

Hell, even if there are multiple plausible mechanisms, the creationist argument still fails because their argument is that there is no plausible mechanism, hence you need divine intervention. This is a classic case of moving the goalpost; any plausible mechanism is enough to demolish their argument, but when you present one, they demand proof that this took place historically.