topics: |  philosophy | evolution | brain | sociology

Excerpts

On Sept 11, 1956, at MIT, three papers were presented at a meeting of the
Institute for Radio Engineers.  One was by Allen Newell and H Simon, "The
Logic Theory machine", (foundational in AI) another by George Miller, "The
magical number seven, plus or minus two" (foundational in cognitive
linguistics), and Noam Chomsky: "Three models for the description of
language" (foundational for linguistics).  In Herbert Simon's 1969 book, he
talks of this occasion and the cordial relations between AI and
linguistics.

But by 1989 the gulf had widened. - p.385

The Chomsky hierarchy of grammars was closely related to Turing's purely
logical investigations of computing processes.  When announced, many
in the humanities, esp foreign-language departments, were extremely hostile
to it.

"Chomsky may be prof of linguistics at MIT, and linguistics may be one of
the humanities, but Chomsky's work was science, and science was the Enemy--
as every card-carrying humanist knows.
    Our meddling intellect
  Misshapes the beauteous forms of things
    We murder to dissect. - Wordsworth" p.386


Chapter 10, "Bully for Brontosaurus", critiques Stephen Jay Gould's ideas
which distort evolutionary theory by undermining adaptationism, gradualism
and other evolutionary processes.

Chapter 13 investigates the role of language as an interface to a group
activity; analyzes behavioural evolution as a possible mechanism that gave
rise to language.  Section 2 debates the positions of Chomsky ("In the case
of such systems as language or wings it is not easy even to imagine a course
of selection that might have given rise to them.")

Review: John Maynard Smith in the NYRB

    Dennett sees Darwinism as a corrosive acid, capable of dissolving our
    earlier belief and forcing a reconsideration of much of sociology and
    philosophy. Although modestly written, this is not a modest book. Dennett
    argues that, if we understand Darwin's dangerous idea, we are forced to
    reject or modify much of our current intellectual baggage — for example,
    the ideas of Stephen Jay Gould, Noam Chomsky, Jerry Fodor, John Searle,
    E.O. Wilson, and Roger Penrose.

    Dennett's central thesis is that evolution by natural selection is an
    algorithmic process. He emphasizes three features of an algorithmic
    process. First, "substrate neutrality": arithmetic can be performed
    with pencil and paper, a calculator made of gear wheels or transistors,
    or even, as was hilariously demonstrated at an open day at my son's
    school, jets of water. It is the logic that matters, not the material
    substrate. Second, mindlessness: each step in the process is so simple
    that it can be carried out by an idiot or a cogwheel. Third, guaranteed
    results: whatever it is that an algorithm does, it does every time
    (although, as Dennett emphasizes, an algorithm can incorporate random
    processes, and so can generate unpredictable results).

    [Two sources for] Dennett's views of the world. The first is a set of
    ideas that includes computing science, artificial intelligence, and
    cognitive science: it is from here that he acquired his conviction that
    algorithmic processes can generate mind-like activities.  The second is
    the gene's-eye view of evolution pioneered by
    G.C. Williams and Richard Dawkins. According to this view, evolution is
    a necessary consequence of the existence of replicating entities; in
    biology, those entities are genes, but the principle holds for any kind
    of replicators. I have thought for some time that Dawkins and Williams
    have made a more fruitful contribution to philosophy than most
    philosophers, and I am pleased to see this opinion so generously
    recognized.
    ...

    Dennett suggests that criticisms of the neo-Darwinist synthesis come,
    in the main, from those who are reluctant to believe that they are the
    product of an algorithmic process. [including Gould].  Stephen Jay
    Gould occupies a rather curious position, particularly on his side of
    the Atlantic. Because of the excellence of his essays, he has come to
    be seen by non-biologists as the preeminent evolutionary theorist. In
    contrast, the evolutionary biologists with whom I have discussed his
    work tend to see him as a man whose ideas are so confused as to be
    hardly worth bothering with, but as one who should not be publicly
    criticized because he is at least on our side against the
    creationists. All this would not matter, were it not that he is giving
    non-biologists a largely false picture of the state of evolutionary
    theory.

    There are, Dennett suggests, three main aspects of Gould's thought which
    reveal a wish to escape from Darwin's algorithmic grip. The first is
    his critique, with Richard Lewontin, of the "adaptationist paradigm." I
    have some responsibility for this critique. As organizer of a symposium
    in London on adaptation, I invited Lewontin, as a well-known critic of
    naive adaptationist arguments, to contribute. Lewontin, for reasons
    that, as an exaircraft engineer, I well understand, dislikes flying,
    and suggested that he write a joint paper with Gould, which Gould would
    present. The result was the now-famous paper entitled "Spandrels of San
    Marco." Its thesis is that many structures in the animal world are not
    adapted for any function, but, like the spandrels of San Marco, are
    accidental and unselected consequences of something else. Further, they
    argued, many adaptive explanations are "Just So Stories," unsupported
    by evidence.

    Two other Gouldian themes, punctuated equilibria, and the
    non-repeatability of evolution, can be dealt with more briefly. The
    tale of punctuated equilibria is an odd one. Its factual basis,
    commonly reported by paleontologists, is that lineages often change
    very little for millions of years, and then change rather rapidly. When
    the idea was first put forward by Gould and Niles Eldredge, it was
    presented as just what one would expect to see if the orthodox view,
    that species often arise by rapid evolution in small peripheral
    populations, is indeed accurate. If only they had left the argument
    there! Their paper would then have been seen as a useful extension of
    the picture given in Tempo and Mode in Evolution by George Gaylord
    Simpson, which was the Darwinian orthodoxy when I was a
    student. Sometimes, however, Gould appears to be saying that the
    changes, when they occurred, were not the result of natural selection,
    but of some other process — genetic revolutions, "hopeful monsters"
    (large mutational changes), or what you will. Since "sudden" in the
    fossil record means thousands of generations, there is no reason
    whatever for supposing any such thing.

    The non-repeatability of evolution — the idea that if evolution were to
    happen again from the same starting point, it would not repeat
    itself — is true, but not new: it is what most scientists have always
    thought. But what, Dennett asks, is the significance of these various
    reservations — anti-adaptationism, punctuated equilibria,
    non-repeatability? The answer, he suggests, is that Gould is trying to
    escape from an algorithmic explanation of life. Dennett may be right.

    The natural selection of replicators — essentially, of nucleic acid
    molecules — may explain the evolution of animals and plants, but what
    about humans? We, surely, are more than the product of our
    genes. Indeed we are, admits Dennett, but it does not follow that we
    are anything other than the products of an algorithmic process. At this
    point, he embraces Dawkins's notion of a meme. A meme can be anything
    from the limerick about the young man of Belgrave (mutated in the US,
    I’m told, to a young fellow called Dave) to the doctrine of the
    Trinity. A meme is an idea that can lodge in a person's mind, and can
    be transmitted, in print or by word of mouth, to other minds. In other
    words, it is a replicator. What is peculiar about humans is that they
    can hold ideas in their heads, and transmit them to others: they
    provide an environment in which a new kind of replicator, memes, can
    evolve. The human mind is another example of a crane. It evolved by
    natural selection, without need for an intelligent designer. Once
    evolved, however, it provides a medium in which a new kind of evolution
    by natural selection can occur, involving a new kind of replicator, the
    meme.

    My uneasiness with the notion of memes arises because we do not know
    the rules whereby they are transmitted. A science of population
    genetics is possible because the laws of transmission — Mendel's laws —
    are known. Dennett would agree that no comparable science of memetics
    is as yet possible. His point is a philosophical rather than a
    scientific one. We see humans as the joint products of their genes and
    their memes — indeed, what else could they possibly be?—even if we have
    no predictive science of meme change. Once a human mind capable of
    harboring memes evolved, a new kind of evolution, cultural evolution,
    became possible, more rapid by far than genetic evolution.

    I [find] Chomsky's views on evolution completely baffling. If the
    ability to learn a language is innate, it is genetically programmed,
    and must have evolved. But Chomsky refuses to think about how this
    might have happened. For example, in 1988 he wrote, "In the case of
    such systems as language or wings, it is not easy even to imagine a
    course of selection that might have given rise to them." This is
    typical of his remarks on evolution. There is, in fact, no difficulty
    in imagining how wings might have evolved. Language is difficult
    because it leaves no fossils; it has evolved just once (unlike wings,
    which have evolved at least four times); and there is an enormous gap
    between the best that apes, whales, or parrots can do and what almost
    all humans can do.

    MODULARITY

    The most interesting claim made by evolutionary psychologists is that
    the mind contains specialized modules that evolved to perform
    particular tasks.

    This is obviously true of that part of the brain concerned with
    analyzing visual input, and, if Chomsky is right, it is true of
    language. It has been proposed that there are also modules concerned,
    for example, with the detection of cheating and with the
    identification and classification of living organisms. Of course, even
    if there are such modules, they cannot be completely isolated. In
    science, as in other fields, progress often depends on seeing
    analogies between apparently different processes. For example, my own
    main contribution has been to see the analogies between human games
    and the things that spiders, trees, and even viruses do. This would
    not be possible if the mind consisted of isolated modules. Although he
    is attracted by the notion of modularity, Dennett warns that the mere
    fact that humans in different societies behave in similar ways cannot
    be taken as evidence of genetic determination. People may simply be
    doing what any intelligent being would do in the circumstances: making
    a forced move in design space, to use his terminology.

    A potentially serious challenge to his position is posed by an
    argument, put forward by Roger Penrose and others, that Gödel's
    theorem can be used to show that human intelligence cannot be
    algorithmic. The argument goes as follows — Gödel proved that there
    exist, within any non-contradictory mathematical system, some true
    statements that cannot be proved. Yet human mathematicians can intuit
    the truth of some such statements. Since anything that can be proved
    can, in principle, be proved algorithmically, it follows that humans
    can do something that algorithms cannot. Dennett replies that,
    although there is no algorithm that can prove a given statement to be
    true, there may well be algorithms that can suggest statements that
    are very probably true. Humans, perhaps, use algorithms of the latter
    kind. Their intuited mathematical truths may just be very good
    guesses. By analogy, a computer programmed to play chess cannot, with
    certainty, find the best possible move, but it does find very good
    moves. Dennett's argument on this point should be read with care. I am
    not sure I have understood it correctly, but I like it, partly because
    I cannot see what else human intelligence could be, other than
    algorithmic, and partly, perhaps, because while I am rather good at
    having mathematical intuitions, I have learned that they are sometimes
    wrong.

                - Genes, Memes, & Minds (1995)