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Our future, our universe, and other weighty topics

Tuesday, February 21, 2017

Dennett's Book Dodges the Real Problems in Explaining Minds

Philosopher Daniel C. Dennett has long been regarded as one of the top apologists of materialism, so no doubt his fans must have had high hopes for his new tome, entitled From Bacteria to Bach and Back: The Evolution of Minds. But the book fails to give us anything like a coherent plausible explanation for the origin of human mentality.

The first part of the book consists largely of Dennett pontificating about natural selection, which Dennett inaccurately portrays as some great creative force. What we have are the typical exaggerations and misstatements of Darwin fanboys on this topic, and they are delivered most dogmatically, with very little supporting evidence. Dennett provides no examples of innovative complex macroscopic features of organisms that have been proven to have originated by natural selection and random mutations –  because no such proof has been produced by scientists. Contrary to Dennett's assertions, natural selection is merely a kind of pruning effect or filter that gets rid of bad designs, not something that has any power to produce complex good designs. Natural selection may describe survival of the fittest, but does not explain the arrival of the fittest. 

 natural selection

The diagram above tells the true nature of natural selection. It is not something that explains the appearance of the yellow circles in the diagram, but merely explains how the red circles got filtered out.

On page 43, Dennett claims that natural selection is a collection of algorithms, and on page 384 he claims that “natural selection is a substrate-neutral family of algorithms.” These claims are false. An algorithm is a sequential set of steps to follow to achieve a particular result, being something that is processed by either a mind or a computer. Natural selection is simply the observational fact of survival of the fittest, the fact that fit things survive longer and reproduce more than unfit things. Natural selection is neither an algorithm nor a collection of algorithms.

The great question about natural selection is: how could this mere pruning effect (which is merely a filter) ever explain the astonishingly complex and coordinated biological complexity we see in the real world? Dennett doesn't explain this in any substantive way, although he very clumsily provides a visual to try to warm us up to the idea that something apparently designed can be produced naturally. He gives us a Science magazine photo showing some circles of stones, and discusses a geological theory that supposedly naturally explains these circles as natural geological effects. The problem with that, of course, is that the complexity we see in biological systems is trillions of times more complex (and gigantically more coordinated) than some little circles of stones.

Later on Dennett has a chapter with the rather silly title “Brains Made of Brains.” On page 155 he advances the frequently stated misconception that the brain is massively parallel. Getting things all mixed up, he states, “Brains are parallel (they execute many millions of 'computations' simultaneously, spread over the whole fabric of the brain); computers are serial (they execute one single simple command after another, a serial single-file stream of computations that makes up for its narrowness by its blinding speed).” To the contrary, human brains do not do many computations simultaneously, and humans can do only one math computation at a time; conversely you can buy desktop computers that actually do dual-processing which is parallel processing.

Sounding like a real Richard Dawkins fanboy, Dennett goes on to a long enthusiastic discussion of Dawkins' idea of memes. But such a discussion is not something that helps at the job of explaining the appearance of human minds. Memes are ideas, and do nothing to explain how we have a mind that produces ideas.

Dennett seems to dodge or largely ignore the main difficulties of explaining the origin of minds such as ours. One of the principal difficulties is the fact that according to the prevailing account, in a period of a few million years hominid ancestors evolved into large-brained humans; but the population of these hominids was supposedly very small when this happened, being no greater than 20,000 or so. The problem is that such a progression would have required many beneficial mutations, and the number of mutations in a population is proportional to the size of the population; so beneficial random mutations in a small population should be incredibly rare. As discussed in this scientific paper, calculations based on known mutation rates suggest that a few million years is way, way too small a time to allow for so many favorable mutations in such a small population, which we should not have expected to see in even 500 million years of time. This “waiting time” problem is one of the chief difficulties of explaining the origin of human minds. But Dennett simply ignores it.

Another set of difficulties lies in the fact that our minds have quite a few characteristics that we cannot plausibly explain by appealing to natural selection. As was pointed out at length in this essay by the co-founder of the theory of natural selection (Alfred Russel Wallace), the human mind has many capabilities and abilities that seem to be impossible to explain by means of natural selection, because they are things that do not improve an organism's chance of surviving in the wild. Among these things are aesthetic abilities, insight, curiosity, philosophical abilities, language abilities, mathematical abilities, spirituality, and altruism. As argued here, none of these things would make an organism significantly more likely to survive in the wild, so we cannot explain them by the idea of natural selection. So how did we get them? Dennett fails to provide an answer.

In my essay I referred to in the previous paragraph, I didn't even mention an additional problem: the difficulty of explaining man's very long-term memory. Humans have memories that can reliably recall things that happened 50 years ago, but this is very much a “luxury feature” exceeding by a factor of 25 what is necessary for survival. An organism would do just fine in the wild remembering things for only one or two years, by just remembering all of the skills and body/location memories it used in the last year or two. Besides being inexplicable from a Darwinian standpoint, our minds capable of storing memories for 50 years are inexplicable from a neurological standpoint. The leading theory of memory involves the idea that synapses store memories. But that doesn't work, because (as discussed here) synapses are subject to very rapid molecular turnover and structural turnover which should make them unsuitable for storing memories for longer than a year.

As far as I can see Dennett completely ignores the whole issue of explaining human memory, not even trying to explain it. He also seems to dodge or largely ignore the main philosophical issue involved in explaining human minds – the issue of how it could possibly be that a merely physical thing could produce the rich mental reality of our consciousness. Philosophers have long smelled an inherent implausibility that any merely physical thing (no matter how complicated its arrangement) could yield the very non-physical thing we call the human mind. For a physical brain to produce Mind seems rather like a stone pouring out blood when you squeeze it.

The only way Dennett seems to handle this issue is through a gigantic cop-out. His fourteenth chapter is entitled, “Consciousness as an Evolved User-Illusion.” I won't describe his nonsensical reasoning, but will merely note that the moment a thinker starts claiming that consciousness is an illusion, he has revealed the intellectual bankruptcy and unreasonableness of his assumptions.

In the last four pages of his book, Dennett provides a grand summary of his explanation of our minds. The summary is an incoherent mess. It starts with the last of his numerous appeals to the authority of Darwin, the type of Darwin showed nature is purposeless talk that thinkers like Dennett give like some Freudian reverently stating Freud showed our anxieties are caused by our childhood sex conflicts. Then Dennett goes on to mention Alan Turing (who helped get computers started) and Shannon (who made contributions to information theory). This seems more like name-dropping than something that helps in explaining our minds. Computers have nothing to do with explaining the origin of human minds. Giving a final salute to Dawkins, Dennett also mentions in italics “words striving to reproduce,” which is a strange personification that does nothing to clarify the origin of our minds. Then in the book's second-to-last paragraph he reiterates his cop-out claim that consciousness is a “user-illusion.”

Of course, by claiming that consciousness is just an illusion, a writer has a convenient excuse for failing to explain it, on kind of the grounds of “there's pretty much nothing there to explain.” It's convenient Dennett has such an excuse, as his book sheds little light upon the origin of our minds. 

Postscript: Today I am reading Evolution and Ecology: The Pace of Life by Cambridge University biology professor K. D. Bennett. Referring to speciation (the origin of species), this mainstream authority says on page 175, "Natural selection has been shown to have occurred (for example, among populations of Darwin's finches), but there is no evidence that it accumulates over longer periods of time to produce speciation in the Darwinian sense."  So why have we been so often told the opposite by Darwin enthusiasts?