Saturday, July 28, 2007

Dawkins #5: "As Much As Possible" is Vacuous

[ This post is number 5 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.

In the last post I showed that pure "increase goals" (goals of increase without condition or limit) have several serious problems. By far the worst is that when the pure "increase goal" metaphor is expanded into literal terms, it's seen to require genes to have states of mind not just metaphorically, but literally. This makes pure "increase goals" incoherent, and that's a show-stopper.

So far I have not discussed "increase goals" with some kind of condition or limit. These can be coherent, and a number of them can be seriously meaningful. At first, a goal of "increase as much as possible" may seem to be an obvious choice among them.

But "increase as much as possible" is deceptive. It probably works, but that's because it's not really an "increase goal". "Do X as much as possible" means "Do X subject to condition Y." "Increase as much as possible" means "Increase, subject to condition Y." The only other goal Dawkins mentions is survival and "as much as possible consistent with survival" is the natural reading of the meaning hidden inside "as much as possible."

If we translate this goal into terms easier to model mathematically, we get "First maximize the probability of survival, and having done that, maximize the number of germline genes." Survival is a demanding goal. Since we are talking about our goal as the candidate for the general goal of natural selection, our gene will be battling for survival against genes selected over eons for their skill at surviving, including their skill in surviving at our gene's expense whenever it's in the slightest bit useful. Unlike increase, which must happen in units at minimum one amino acid in size, survival is a probability. Arbitrarily tiny advantages built up over time can make a difference.

The issue may be clearest if we look at the goal of "first maximize survival, then decrease the count of germlines genes as much as possible". This goal is coherent, and we don't have to worry about a gene with this goal decreasing itself to extinction. The first priority for the gene's efforts is survival. No effort will be available for any second priority.

If the gene's goal is "first maximize survival and then do Z as much as possible", Z can in fact be nonsensical. For example, Z might be "attend Rolling Stones concerts" and the fact that genes don't know how to buy tickets will make no difference -- they'll never have the chance to worry about it. The "do Z as much as possible" clause is completely vacuous.

Perhaps the reader never had any taste for slippery language like "as much as possible", and has been wondering why I'm going on about it. If so, I apologize. Goals like "increase the germline gene count until you've used 9.7601% of the Antarctic biomass, then sustain that biomass level" are both coherent and substantive. Unlike the incoherent and vacuous versions of the "increase goal" that I've been discussing, which can be dismissed a priori, specific gene-frequency goals are likely to reward empirical investigation. Even so, I think they are inferior to survival as a choice for the general goal of natural selection, and in my next post, I'll show why.


Harshad said...

What about "increase population" being a sub-goal of the "survive" goal?

And the limited increase law need not really be a law. Like you pointed out, uncontrolled increase is not practically possible; so the "increase count" goal is self-regulating (to use yet another metaphor :) )

Jeffrey Kegler said...

I'm going to be delayed in answering harshad's question, for which I apologize. I'm driving across the U.S., from Masschusetts to California. (I'm now in Indiana.)

This has been very much a slow motion blog. But also I think it is good to think these issues out thoroughly and I, at least, can't do that quickly.

Jeffrey Kegler said...

I've replied to harshad in a post in the main blog. My apologies to harshad for the delay. I was in the middle of moving to California when his comment came in.