Is Wright's Argument Any Good?
Before continuing on with the discussion of what Dennett said vs. what Wright said he said, let's pause to consider whether Wright's argument is actually any good.
We have already seen that Wright's argument depends critically on the analogy between embryonic development and the evolutionary process generally. The analogy is roughly that in both cases we go from simple beginnings to functional complexity and diversity. If there is anything more to the analogy than that I'm not sure what it is.
The trouble is that there are obvious differences between ontogeny and evolution. In ontogeny we see the unfolding of a genetic program. Thus, the embryo goes from uniform simplicity to diversified complexity because of the instructions encoded in the genes and the cellular machinery that exists for decoding those instructions.
The process by which natural selection crafts complexity is entirely different. Natural selection does not represent the unfolding of a preordained program. Rather, it represents the end result of many years of trial and error. There is no guarantee that his process will lead to anything more complex than you started with. And even if you do, there is no guarantee that complexity will not increase for a while, and then plateau, having reached an evolutionary cul-de-sac. There is definitely no guarantee that anything like higher intelligence will emerge.
Now, elsewhere in the interview Wright expresses his belief that intelligence was indeed inevitable as a result of the evolutionary process. This assertion imparts a clear directionality to evolution. Dennett, by contrast, was far more circumspect about the sense in which evolution leads to complexity. He points out that over the “long, long, long haul” we can say that evolution will probably lead to human-like intelligence but that it is not guaranteed to do so in any finite length of time. He also describes the evolutionary process as being like a sawtooth function. Complexity will steadily increase for a while, but then the whole thing might come crashing down, say as the result of some natural catastrophe. But then it will start building up again.
So I think the analogy breaks down completely.
There is another point to be made. In embryonic development we do not have a single natural law or process causing a particular effect from a given cause. It is not comparable to saying that a rock released close to the surface of the Earth falls to the ground because of the effect of gravity. Rather, the process of development is itself so complicated that it needs to be explained in terms of something else. Most biologists would answer that the processes of development are themselves the product of natural selection.
For Wright's analogy to be valid we would now have to argue that evolution by natural selection is so complicated a process that we can not think of it as a simple natural law in the same sense that the law of gravitation is such a law. Rather, it had to emerge as the result of some sort of design process.
But this doesn't seem right. Evolution by natural selection is a simple consequence of having imperfect replicators competing for resources. That this process can, in some cases, lead to great complexity does not mean the process itself is incredibly complex. I think this is another point where Wright's analogy breaks down.