Re: [asa] Amazing Proteins

Hello Mike--

I think I have gleaned the gist of your question from these two excerpts:

"I think a better way of saying it is that evolution has been quite
successful because of proteins. After all, there doesn't seem to be much
evidence that the blind watchmaker can do all that much without the help of
proteins."

"I don't argue that proteins are essential for evolution. I am suggesting
that evolution has been quite successful because of proteins. After all,
why don't you have other data points to point to?"

I think others have noted that you seem to be constructing a fine-tuning argument, or at least a claim regarding an instance of fine tuning. I don't care for fine-tuning arguments myself, and I won't address the merits or utility of such discussions here. Instead, I want to point to what I see as some very significant weaknesses in your premises, weaknesses that make your idea unworthy of serious further consideration.

First, you claim that "there doesn't seem to be much evidence that the blind watchmaker can do all that much without the help of proteins." This type of argument (from ignorance) is so vacuous and fallacious that it damages your credibility as a commentator. The best you can say is "we don't know", which is lame enough, but in this case there are some solid ideas about non-protein chemistries that may underlie the origin of life. Catalytic RNA itself is a solid rejoinder to your challenge, but even if there were no ideas at all regarding alternative (or primitive) chemical bases for life, the "lack of evidence" claim is a thoroughly unsound basis for concluding anything in an area about which we know so little.

Second, you claim that "evolution has been quite successful because of proteins," but we all know that you can't produce a comparative study that justifies this conclusion. Specifically, I note that you have no solid basis for asserting that protein-based life is superior to other formats, most of which we likely can't even imagine.

Finally, you are overly impressed by the current absence of other chemistries. In fact, this absence is the only observation you can produce in support of your idea, and I gather that you favor the conclusion that protein-based life out-competed other formats (or that the other formats never even existed) by virtue of surpassing excellence. It is certainly possible that protein-based life is superior (from an evolutionary standpoint, at least) to most or all other options, and that this explains why life as we know it is protein-based. But there is at least one other explanation for the emergence of a protein format in the absence of others, and it arises from the consideration of contingency in the trajectory of evolution. If you have a copy of Jonathan Weiner's The Beak of the Finch, check out page 301, where he discusses this very question. "Possession, as we say, is nine-tenths of the law," he begins, referring to biological niches, such as the Galapagos Islands upo!
 n the arrival of the first finches. When self-duplicating molecules first arose, they could "grow at their own pace," because "all paths lay open." But once "life" got off the ground, some paths started to disappear -- they were blocked by already-successful replicators with a head start. Here's the key paragraph:
"In the laboratories, the trial soups are kept hermetically sealed, or each experiment would be cut short before it got interesting because the new molecules in the soup would be scavenged by bacteria. The waiting Pyrex ponds are sterile as the seas and shorelines of this planet before life began. But in the ocean, of course, as fast as molecules make their first gestures toward life, they are devoured. Creation in the sea has never stopped, but the niche of life is taken."

Yes, proteins are cool, really cool. But don't put so much stock in your inability to imagine better paths, and don't make the mistake of assuming that protein-based life dominates today due to victory in a planetary round-robin tournament.

Steve Matheson

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Received on Sun May 11 22:28:49 2008