Saturday, July 21, 2007

Dawkins #3: Do Genes really Care?

[ This post is number 3 of a series. They will be of interest mainly to those who've read Richard Dawkins' book, The Selfish Gene. I recommend they be read in order. ]

In previous posts I identified two distinct goals Dawkins ascribes to genes: "survival" and "increase". I pointed out that these produce different models, models that will often predict different results.

I've been speaking of genes which "strive" to achieve "goals", and which "care" about outcomes. In this I've followed Dawkins, who finds it a helpful metaphor. We're dealing with foundations, however, so we need to be careful. Neither Dawkins or I imagine that genes are really conscious, much less that they actually have goals. It's time to slow the pace and speak more literally.

Let's look at a snapshot with a single gene in it. In the rare case our snapshot is of a recent mutation, we toss it in the trash and select another. That guarantees that our gene is the result of a long process of natural selection. Our gene, typically as part of a complexly organized team of genes, has passed a long series of stringent tests.

For example, if it's a gene in a cuckoo, a bird that lays its eggs in the nests of other birds and whose nestlings must trick the other birds into rearing them, it "is descended from a long line of ancestral cuckoo nestlings, every single one of who must have succeeded in manipulating its foster-parent. Any cuckoo nestling that lost its hold, even momentarily, over its host would have died as a result." (Dawkins, The Selfish Gene, 30th Anniversary Edition, 2006, p. 250). None of the genes in those nestlings who failed momentarily and died would, of course, have survived to be in our snapshot.

The gene's success is not because it, or anything or anyone else, planned for it. All the gene did was produce the amino acids which its chemistry forced it to produce. Fortunately for the gene, these were animo acids which helped produce successful cuckoos, generation after generation.

The gene in our snapshot originated long ago in a mutation, a random, purposeless accident. There were many other mutations, random like the one which created our gene, and almost all of them were disastrous. Those other mutated genes usually killed any cuckoo unlucky enough to inherit them, and disappeared along with the birds they killed. Because it is in our snapshot, our gene was one of the very rare ones which did not result in failure. It somehow survived alongside other, already successful germlines. Our gene may have added useful variation to the genes already in the cuckoo gene pool and found a comfortable niche among them. It may have survived by pushing other genes to extinction. Because it is in our snapshot, we know that whatever it took to survive, our gene did it.

At no point did our gene, the cuckoo, any other gene or anything or anybody else think this out, form any plans or set any goals. The gene in our snapshot was the result of a long series of accidents, each one by itself completely without purpose or meaning.

But over the millenia, this random series of separately meaningless events became something our brains see as having a purpose. This cuckoo gene produced amino acids which resulted in an intricate mix of behaviors and traits which resulted in the gene being in our snapshot. As for any of its comrade-genes that during that long period produced even slightly less successful amino acids, they are nowhere to be seen.

So it feels natural to us to speak of the gene as having undertaken the project of surviving so that it could appear in our snapshot. The length of the process which brought it into our snapshot makes it natural for us to speak of the gene "striving", of it "caring" about whether it wound up in our snapshot or not, and of it having "survival" as its "goal". The complexity of that process makes it natural for us to speak of the gene "planning" that success. The idea of genes which "care", and are "selfish" or "altruistic" comes naturally to our minds and lets the non-linear parts of our brain assist in putting together a picture of natural selection. But we need to remember this anthropomorphic language is a metaphor, and we must always be prepared to translate the metaphor into the unconscious, random processes which are the actuality of natural selection.

The reader who's been following me carefully will have noticed that "snapshot" was a crucial choice of words in the above. If we think of our selection of a gene for our thought problem as a "snapshot", the "goal" that falls out of following Dawkins logic through the "thought problem" is "survival", instead of an increase of the number of germ-line cells.

"Snapshotting" is the simplest way to picture sampling genes for our thought problems, and the above description shows it's a natural way of looking at the problem. But while simplicity and naturalness can and should give the feeling that we are on the right track, they are not proofs. Might not other ways of sampling genes for our thought problem result in the "goal" appearing to be an increase in the germ-line population?

If we view our sampling not as a "snapshot", but as some kind of "random sample", concepts of gene frequency enter into the picture. As natural and simple as the snapshot/survival viewpoint is, might not the viewpoint based on "random samples" be more revealing? And if so, wouldn't that support seeing the gene's goal as "increase"? In my next post, I'll examine that issue.

No comments: