What natural selection cannot explain…

In the unlikely event that there is some version of creationist reading this, you will not find anything you like. Go away*.

I wrote about human language and whether deaf people also have the ability for language, (which would show that language is innate and not cultural), and whether language affects the way a person thinks, of which a stronger version is asking if we ‘think in’ a certain language.

It was in this context that Nair and I were arguing about whether evolution by natural selection optimizes the design of living organisms. Nair says, and I agree, that language is richer than would be required to just communicate with other members of the species.

Language did not have to be rich enough to allow Shakespeare’s ‘…to be or not to be’ or Wordsworth’s ‘Ten thousand saw I at once’, to function as a medium of communication. Nair says that this is proof that language is culturally evolved and not through evolution by natural selection. His contention is that evolution optimizes everything, and, therefore, that evolving language is overkill and natural selection could not have created language.

I disagree. Natural selection is not a benign force that wants to optimize the overall utilization of resources. What natural selection does maximise, and this is the central point here, is the survival of genes in some species. What should be underlined is that the gene pools of different species are, by and large, separate, which means that each gene pool will move towards a maximum number of copies of its genes.

For example, this means that in trees (and this is an example that Nair and I argued about), when a slight increase in height means slightly better oxygen supply, slightly better sunlight, and (perhaps) slightly better dissemination of seeds, natural selection will invariably choose genes that increase height. This leads to the creation of insanely tall trees, even with the trouble that such height can cause (more water and nutrients are needed, and the vasculature has to work overtime; the girth has to increase to provide enough strength).

This, when the obvious optimum would have been all trees of a particular species being roughly similar, and only tall enough to get enough oxygen, and sunlight and birds. A whole forest of trees getting slightly less sunlight is more optimal than a single tree getting the sunlight of Mercury, and everything else either being in the dark and dying out, or matching the former inch for inch.

A somewhat loose analogy is that natural selection cannot get to an optimum that cannot be reached in minute steps. There’s no foresight, and therefore, natural selection can only choose what’s better at any given generation. It cannot plan for future optima at the cost of the present generation. Yes some sort of median height for all trees would be better, but there’s nobody to know or understand this.

At this generation, is a slightly larger height better? Yes. So choose the genes that lead to more height. ” And so on and so forth.

What natural selection cannot explain is why trees get to be only so tall and no taller. No, I’m not saying that somebody put a glass ceiling up there. I’m saying that the factors that decide how tall trees can be aren’t part of natural selection. The factors, in this particular example, are these: (x) How tall can a tree be before the smallest wind topples it? (x) How tall can a tree be before the energy required to pump nutrients to the highest branches becomes too much for more height to be useful? (x) How tall can a tree be before the concentration of nutrients in the ground falls short of what is required to keep up the growth? And so on. Natural selection isn’t part of the answers to any of these questions. There are very simple physical answers to the questions, of course. They just don’t fall under the purview of natural selection.

What this translates into for language, as far as I can tell, is that if communicating slightly better gives some human being an edge over other humans, evolution will favour reproduction of the genes that led to the better communication. So much is fairly standard. What Steven Pinker argues in his book, The Language Instinct, is that natural selection, in its usual zeal seems to have put into place a much more elaborate framework for language than is necessary for communication. He shows that this framework is universal among Homo sapiens, and that all human languages fit into this framework, the language instinct. He also tracks down, insofar as is possible, the genetic basis for this language instinct.


* Hat Tip to Vikrant ST Gupta for this usage. He uses it as a phrase of endearment, and not with nearly as much contempt as I have here.


5 thoughts on “What natural selection cannot explain…”

  1. In this fiction, I sound like a creationist (not the Wilberforce type) going up against Dawkins or Huxley.

    First of all, I do believe we have an innate language of thought (mentalese) which is different from spoken or written (or typed) languages or pidgins or creoles. Evolution (which comprises random mutations + non-random natural selection) might have favoured a language instinct. It is for instance highly advantageous to have some medium of expression which can travel beyond the line of sight (alarm calls, some mating rituals, show of authority etc). I guess my point of contention was in your restriction of this instinct to humans. In other words you say non-human animals do not possess a language instinct. You call it communication instinct but I don’t see where you would draw the line.

    To me spoken languages are more memetic than genetic as it involves exchange of ideas (memes) from the talker to the listener. Natural selection created sophisticated brains which in turn created languages. So yes, languages evolve, but culturally.

    What natural selection tends to do is “trap” us in a Goldilocks’ zone through an evolutionary arms race. I’m not suggesting any intentionality but the point is trees cannot grow beyond a limit nor can they afford to be shorter than others. That said, the optimum height for a tree in a meadow is much shorter than for one in a woodland. In a forest, in the absence of any intentionality, the best you can do is be the tallest you can. And natural selection drives the trees into this optimum. If there was some intentionality, all the trees (or the designer) would have “agreed” upon a much shorter length to save the expenses. Hence, I don’t see how evolution went overboard in the case of language instinct in humans. It just provided fertile grounds for a memetic evolution of which spoken language is a by-product.

    Sorry for the post length comment. (evil laugh).

  2. Can non-human animals not have the instinct? Nobody’s saying that. It is, however, claimed that they don’t . We seem to be the only species capable of language. It seems like you think this is some form of speciesism. It isn’t. Let me assure all the chimpanzees, gibbons, gorillas and orang-utans reading this that I have nothing against the great apes.

    Also, this:

    What natural selection tends to do is “trap” us in a Goldilocks’ zone through an evolutionary arms race. I’m not suggesting any intentionality but the point is trees cannot grow beyond a limit nor can they afford to be shorter than others. […] And natural selection drives the trees into this optimum.

    I wrote specifically about this! The constraint that forces natural selection to stop selecting for genes that would increase height is not also part of the process of natural selection. The constraint is physical (any taller and the tree topples => no more seeds => no more reproduction => no more survival of genes that increase height). You could, if you twist your arguments into a bunch, make the physical constraint (vaguely) part of natural selection; all I’m saying is that that is unnecessary to understand evolution by natural selection.

    In humans, we could’ve had the same level of communication as the great apes (now… is it possible that the ancestors of us and the apes had the instinct, but some of them lost the instinct and became apes?). That might have been enough to ensure survival. Romeo didn’t really have to woo Juliet with poetry for the human race to survive, did he? I mean… Juliet had to come into heat sometime and pick someone, right?

    PS: Comment length, Bah.

  3. This is something specific to the ‘spoken languages are memetic’ thing. Obviously, I don’t know nearly enough about linguistics, but as far as I can remember from Pinker, the basic architecture required for language – the noun-type, the verb-type, the placeholder-type, etc – are already in place in human beings. This architecture is the language instinct.

    That languages and their oddities themselves are culturally evolved may well be true.

  4. >>>Nobody’s saying that. It is, however, claimed that they don’t <<<
    No comments on that.

    You are using unnecessary jargon just to confuse people. I don't see any difference between what you call "physical constraint" and deleterious mutations. What are harmful mutations but those which try to push beyond (in a bad way) limitations set by nature. Natural selection depends on environment (hence the name) but not the mutations. The optimum tree length is different in a grassland and a forest.

    PS: I only hope people don't turn into chimpanzees and gibbons and gorillas and orang-utans after reading your comment.

  5. Yes. I plead guilty to that ‘distinction without a difference’ charge. Deleterious mutations are deleterious only because of the environment of the organism, so maybe I was splitting hairs.

    We’ll have to read that paper , won’t we, to find out whether tree height is ‘optimized’ or whether natural selection just goes crazy?

    Updates will be provided. Watch this space!

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