Monday, June 9, 2014

The End of Evolution

I'm the first to admit I am not a philosopher, but this article in the WSJ seems to me to betray a massive amount of confusion on the part of some defenders of natural selection.

In a nutshell, Dr. Keleman is saying that we need to understand natural selection without recourse to "teleology" and "design". Well maybe if that is our goal we should refrain from using the word "selection"--because the minute you say "selection" you are implying a selecting agent and a process which implies a goal and an end. But we'll lay that aside for a moment to attack the larger point.

Dr. Kelemen primarily objects to kids explaining "biological facts in terms of intention and design, such as the idea that giraffes develop long necks because they are trying to reach the high leaves."

Hence the example of the pilosas:

Dr. Kelemen and her colleagues thought that they might be able to get young children to understand the mechanism of natural selection before the alternative intentional-design theory had become too entrenched. They gave 5- to 8-year-olds 10-page picture books that illustrated an example of natural selection. The "pilosas," for example, are fictional mammals who eat insects. Some of them had thick trunks, and some had thin ones. A sudden change in the climate drove the insects into narrow underground tunnels. The thin-trunked pilosas could still eat the insects, but the ones with thick trunks died. So the next generation all had thin trunks.
Whoa. Wait a second though. Does this really argue against teleology and design?

Dr. Keleman seems to be arguing that the trunk width of pilosas was just a random happenstance that a random climate change operated on in a random way. And I often hear people throwing the concept of "randomness" around a little too freely when it comes to evolution.

But let's not forget something. We tend to think of sexual reproduction as a given because we reproduce that way and most organisms that we know of reproduce that way. But it isn't a given at all. There are plenty of organisms who can clone themselves.

Any gardener can tell you there is an inherent advantage of cloning. A clone assures you of getting the exact copy--so if a vine has exceptional grapes, the clone will have exceptional grapes as well. But an exact copy can be a mixed blessing--in that it transmits not only all of the benefits of the original but also the disadvantages of the original. If that exceptional grape vine is very susceptible to attack by disease, for example, then all its clones will be equally susceptible.

If a plant breeder wants to improve on the original vine by, say, keeping the exceptional grape but also reducing its susceptibility to disease, there is only one way to do that. And that is to forget about cloning the thing, and sexually reproduce it. In other words, breed the grape with another grape, and select from the offspring.

This is the essential element that Dr. Keleman is missing: that genetic variability in a population is, in fact, no random result but rather an end that was deliberately sought and achieved. The very fact that there were pilosas with different thicknesses of nose is an adaptive end of meiosis and sexual reproduction. That is exactly what they are there to bring about.

In other words, the genetic lines of the pilosa were designed to have a certain level of variability specifically to mitigate against the kind of environmental changes Dr. Keleman is talking about.

She introduced the fictional scenario of the pilosas' prey going into underground tunnels. That's a plausible scenario. But we can offer completely opposite ones. Suppose it was a spate of frigid winters, such that the appendages of small animals would be extremely susceptible to frostbite. In that case, the thick-nosed pilosas, with their increased nasal mass, would likely fare better than the thin-nosed ones.

The pilosas, like all organisms, are not mind-readers. They are not prognosticators. No creature, rational or not, can direct itself or be directed to an end that is unknown.

So they do what any sensible, rational human being would do when faced with wealth to protect and a set of unknown circumstances to defend it in: diversify.

Genetic diversification is, itself, the purpose, the intention, and the design behind sexual reproduction. Meiosis and sex exist specifically to provide it.

This is why Dr. Keleman's argument falls flat. Arguing against teleology on the basis of environmental randomness is nonsensical. You might as well argue there is no intention or design in a diversified portfolio because of the randomness of the economy. You might as well argue there is no intention or design in a computer program because of the randomness of its variables.

There absolutely is an end. There absolutely is a design. An end and a design that, like the investor and like the computer coder, recognizes the inherent instability of the environment and has built in a way of dealing with it.

It seems to me that the "folk biologists" here--the natural tendency kids and others have to explaining things as the result of design--are actually exactly correct, where Dr. Keleman is the one who needs a philosophical reorientation. The pilosas did have an end in mind. Their end was to live. To reproduce. To survive and pass on offspring to the next generation. That's the teleology.

In that sense, giraffes DO, in fact, develop long necks because they want to reach the leaves--they want to reach the leaves because they want to live.

No no no, the dogmatic biologist may object, reacting against this bit of "Lamarckism." It's completely random, he asserts. But he is wrong. Meiosis and sexual reproduction may seem to us to give random results. But they are no more random than the various asset classes in the portfolio or variables in the program code.

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