August 22, 2005

ID - it's How Not to Plug the Gaps

from - smijer

Let's start with an apology and explanation for the recent slowdown on my side of the table. School has started for the kids, changes at work leave me with no down-time, and the world, as usual, goes on at a crazy pace leaving me to stare bewildered as its fleeting images pass by without ever fully registering in my consciousness...

Oh, and I've exchanged my very few minutes free blogging time for a debate in the comments at the Jeff Blogworthy blog on the subject of "Intelligent Design".

And, I don't have much to add to the subject. I'm not a scientist by any stretch; my education in biology is limited - in fact, it approaches zero. But that doesn't keep the right side of the blogosphere from opining on the subject, so I won't let it stop me, either. If you are looking for good commentary on the subject, I highly recommend you leave this post immediately and go fishing at The Panda's Thumb blog, at Pharyngula blog (here it will be sandwiched between mollusc porn and liberal political commentary), Chris Mooney's blog, or the ever helpful website.

Still here? Don't say I didn't warn you. Ok, not even its proponents will take issue with the characterization of ID as a criticism of the Darwinistic mechanism - essentially a conviction that gaps in our knowledge about the evolution of various biochemical systems could not have evolved by currently understood Darwinistic mechanisms, and that "only intelligent design" can explain their existence. So, basically, ID is a "God of the Gaps" argument. X does not (and cannot explain Y), so God did it.

What is unscientific about this approach is that Intelligent Design, aka the Hand of God, isn't treated as a theory meant to explain Y, aka "specified complexity" in biochemical systems, with specific predictions that could be used to test the theory. It is, instead, a default position. If we can prove that the task would have been too hard for Darwinian mechanisms, then we must accept that Design is behind it. Which leads to one standard criticism of ID - that the ID movement has yet to prove that any specific task is really too hard for the standard darwinistic explanations including natural variation and selection. In fact, the systems put forward by the IDists as being key "evidence" for design are, in fact, probably evolved by just those mechanisms, though their history is too ancient and left too little evidence for us to be able to show conclusive evidence of that at this time.

But, for the sake of argument, I want to talk about another system that puzzled "evolutionists" mightily for a long time, and for the sake of argument, I want to suggest that the IDists could have proven that they did not evolve through a gradualistic, darwinistic, pathway - as in fact they did not. I am talking about the eukaryotic cell structure. If Behe, Denton, Johnson, and Dembski had been around at the time, this might have made excellent fodder for their ID arguments. They might have pronounced "Darwinists" willingly blind to the inability of their mechanism to produce the cell structure of eukaryotes, with its complex and specialized division of labor from their relatively simple prokaryotic ancestors.

So, while our hypothetical 1970's IDists would have been telling us that the eukaryotic cell structure was a significant challenge to certain tenets of the neodarwinian synthesis (it was), that scientists refused to acknowledge it (they didn't), and that it was evidence for Intelligent Design (it wasn't), Lynn Margulis was busy solving the problem, brilliantly and beautifully. The answer was endosymbiosis. It is reminiscent of the adage that, "those who say it cannot be done should not interrupt those who are busy doing it."

A common ability of eukaryotic cells is "phagocytosis", the ability to eat things by pulling them in, engulfing them, and letting their cell membranes become bubbles around them ("food vacuoles"). The contents are then digested by having digestive-enzyme-containing lysosomes fuse with them. After the digestion is finished and desired molecules absorbed, this bubble can be pushed toward the cell membrane and its contents released ("exocytosis").

Many protozoans (animal-like protists) eat by phagocytosis, and various animal immune-system cells, called hemocytes in invertebrates and phagocytes in vertebrates, also do this.

But consider the fate of a victim of phagocytosis that escapes being digested. It can live inside its "eater" and even proliferate, as the likes of Buchnera and Rickettsia do. And it is only a small step from there to a closer relationship.

Origin by phagocytosis also explains the double membranes of mitochondria and many chloroplasts; the inner membrane is the organelle's original membrane, while the outer membrane is the original food-vacuole membrane.

This is what happens when people take scientific challenges seriously, rather than using them as grist for a political effort to get God back into schools.

And this is why those who believe in a great God should not try to shrink their Deity down to the size of a gap in scientists' knowledge... because that does not only diminish God by the shrinking, eventually it will further diminish the Lord of the Universe as scientists' knowledge expands... And this is why the rest of us should not shrug our shoulders and say "God must have done that" every time we run across a puzzle that just doesn't seem to make sense according to our current understanding of science.

The end.


Posted by smijer at August 22, 2005 08:10 AM

There have been a couple of letters to the editor in our local paper recently lambasting the Intelligent Design movement.

Being as unscientific as I unapologetically am I get a kick out of both sides.

I find the statement "God did it" no more outlandish than "Hey ya'll, one time there was this Big Bang..."

Shit. Let there be light.

For whatever reason this is a life and death issue for two sides and as usual I am outside looking in.

univar.jpg Posted by Buck on August 22, 2005 08:59 AM
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