Wednesday, July 25, 2007

Dawkins #4: Pure Increase is Incoherent

[ This post is number 4 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. ]

Richard Dawkins ascribes two different goals to genes: "survival" and "increase". In previous posts, I pointed out that these produce different models, which in turn predict different results. I expanded the "goal" metaphor out into literal terms, and showed that if this "thought problem" is worked out with genes taken on a "snapshot" basis, their goal is clearly seen as survival.

But I have not shown what happens if we run through the "thought problem" using methods of sampling that take into account the frequency of genes. And while I showed that "survival" works as a goal, I did not show that "increase", that is, increasing the number of germline genes, does not work even better as a goal.

If we look at multiple "snapshots" of genes from a frequency point of view, then the genes might be seen as having a goal of appearing in as many snapshots as possible. In this case we might be able to work through the "thought problem" in a way that justifies us in saying they have a goal of increasing their frequency in the sampling.

Devising an sampling method that's right for calculating gene frequency in the "thought problem" is not easy. There are genes deep in the ocean and deep inside the earth of which we know very little. And what of genes that may be traveling on meteorites, or elsewhere in the solar system? The sampling method needs to make sense as something that genes would seek to optimize. The sampling won't make sense as a "goal" for genes if it is biased in favor of genetic material that's easy for humans to find, or even in favor of genetic material humans know about.

Since we are dealing with a "thought problem", the sampling method can be one difficult or even impossible to carry out in practice, but that still leaves issues of definition. And if we can't measure what we say genes are optimizing, we can't test our assertion that they are selfish.

Picking a sampling method is not an issue for the "survival" goal. All the survival goal asserts, is that any gene having survived many generations of intense competition to end up in a snapshot can be said to have the "goal" of ending up in the snapshot. The logic of the survival goal is on a snapshot-by-snapshot, gene-by-gene basis, and sampling issues do not come up. Only if we are using frequency as determined by a sampling, which we have to if we want to define an "increase goal", does it matter whether the sampling is arbitrary, or biased.

The sampling issue may be solvable, at least in principle, so I will assume that it has been solved and move on. Increase goals have other, more serious, problems.

The pure form of the "increase goal" is incoherent. Nothing that comes in finite pieces can increase indefinitely. Every increase in the number of germline cells must be of a minimum size, certainly no smaller than the smallest possible amino acid. Long before the entire mass of the solar system is used up by germline genes in a single locus and for a single phenotype, increase must come to a halt.

At first glance, this may look like an unfair quibble. Take the statement that "Charles Ponzi's goal was to increase the amount of money in his Security Exchange Company." Ponzi's scheme itself may not have been sound or coherent, but it is certainly coherent (and probably true) to say that unlimited increase was Ponzi's goal. It is not incoherent to state that someone has an incoherent goal.

But there's a crucial difference between Charles Ponzi and a gene. A gene's goal must be coherent in terms of our "thought problem". That is, the "goal" ascribed to a gene must still make sense when the metaphor is translated into literal terms. Genes do not have minds in which to form schemes, and if translation of a goal into literal terms requires genes to have a mind of their own, then saying that genes have that goal is incoherent.

We are entitled to decide that Charles Ponzi had certain plans even if he never fully carried them out, in fact even if it would have been impossible for him to carry them out. We can do this because we believe Charles Ponzi was, in literal fact, a conscious being with a mind in which such a plan could exist. Based on Ponzi's actions and statements we can ascribe unrealized and even impossible goals to him.

We are not entitled to ascribe any "goal" to a gene if it means that we are stating that the goal was only in the gene's "mind". The gene has to actually carry out its goal, or we have no basis to say it was the gene's goal. We can't say that genes have the goal of unlimited increase, because we could never see them actually carry this goal out. Humans can be said to have impossible or unrealized goals, but genes cannot. Genes don't think and we can't go beyond metaphor and use the language of "goal" in a way that requires genes, literally and as a matter of actual fact, to have minds of their own.

I did not originally intend to use Charles Ponzi for my example. I'd wanted to use the statement "Richard Dawkins' goal is to increase the number of atheists" instead. But I couldn't, and the reason I could not is relevant. It's very difficult to come up with an example of a "pure increase goal" that doesn't involve insanity or delusion, because in the real world most such goals hit limits.

Dawkins, once he had converted every last man, woman, and child to atheism, would stop. (At least I think he would.) I assume, for example, that he would not go on to try to create a population explosion in order to further add to the count of atheists. Ponzi was the kind of wild optimist who does not think about potential obstacles. Deluded people like Ponzi can more easily be spoken of as having pure increase goals. A real gene with anything close to a pure increase strategy, in practice, would be likely to drive itself to extinction by overexploiting the resources it needs to survive, a fate not unlike that of Ponzi's scheme.

To be coherent, an "increase goal" must be impure, that is to say, limited in some way. In the next post, I'll comment on some "increase goals" which are limited and coherent, and explain why they also don't work as alternatives to the survival goal in explaining natural selection in general.

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