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Topic: William A. Dembski: Reflections on Human Origins
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Moderator
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posted 22. June 2004 08:23
Reflections on Human Origins
by William A. Dembski
Abstract:The evolutionary literature treats the evolution of humans from ape ancestors as overwhelmingly confirmed. Moreover, this literature defines evolution as an inherently material process without any guidance by an underlying intelligence. This paper reviews the main lines of evidence used to confirm such a materialist view of human evolution and finds them inadequate. Instead, it argues that an evolutionary process unguided by intelligence cannot adequately account for the remarkable intellectual and moral qualities that we see exhibited among humans. The bottom line is that intelligence has played an indispensable role in human origins.
To read the entire paper, click here.
Note: New version of this paper uploaded August 5th, 2004
[ 05. August 2004, 20:33: Message edited by: Moderator ]
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Scott
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posted 02. July 2004 17:22
I have read the paper, however, I would in this post like to first offer a few comments on the material in the abstract.
The abstract makes the following statements, each of which I believe will require either modification or further elucidation:
A : "The evolutionary literature treats the evolution of humans from ape ancestors as overwhelmingly confirmed."
Humans may indeed be portrayed as evolving from ape ancestors, but a statement such as this will need to be supported with references, else it is in danger of being called a straw man. A less controversial way to phrase this is as follows:
A' : The evolutionary literature treats the evolution of humans and apes from a common ancestor as overwhelmingly confirmed.
B: "Moreover, this literature defines evolution as an inherently material process without any guidance by an underlying intelligence."
Again, a statement such as this will need to be supported with references.
Question : What is meant by the phrase "evolutionary literature"? Does this refer to popular books, textbooks, published peer-reviewed papers, or some or all of the above? Depending upon references cited, this phrase may need to be made more explicit.
I have no doubt that this paper will not receive a favorable reception by the critics of ID and feel it is particularly important that we ID proponents be precise in our terms and support our assertions with references. This should be particularly important to you, I believe, because you will also no doubt be attacked on your "lack of knowledge" about biology in general and human evolution in particular.
Of course, perhaps your paper is meant to have as its audience only the "true believer." I hope that is not the case.
regards
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The Deuce
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posted 08. July 2004 21:08
One other suggestion I'd like to add to what Scott said. Towards the end of the paper, you state:
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Evolution, as the term is typically used, refers to a process of modification that explicitly rules out intelligence. In other words, evolution by intelligent design is not typically what is meant by evolution.
Since the term is used throughout the essay, I think it would be better to put this clarification near the beginning rather than near the end.
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Rex Kerr
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posted 09. July 2004 01:13
I need to read the paper in more depth to address the many disagreements that I have with its conclusions and method of argumentation. (For instance, cases where single instances of unexpected mental performance based on brain structure are held up as critically important, notwithstanding literally tens of thousands of examples of loss of mental function due to brain damage!)
However, it strikes me that this article is remarkably badly timed to take advantage of the draft chimp genome. Preliminary results already have revised estimates from "98.5% similarity" to "1.4% divergence due to point mutations and 3.4% divergence due to indels". See the article by Britten, PNAS 99:13633 (2002). The extensive discussion of similarity is thus already almost out of date, and will be completely supplanted by the near-complete chimp genome data that is already out and is now being analyzed.
Thus I would strongly encourage a major revision once the comparative genome analysis work has been published.
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Rex Kerr
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posted 09. July 2004 03:40
Ack, it looks like I'm double posting here, too.
Anyway, here's my critique of Dembski's arguments.
First, I don't see how the Sidis story argues for a difference in kind rather than a difference in degree between us an animals. Most humans do not have cognitive abilities like those that Sidis reportedly had. Appearance of people like Sidis would argue that the fundamental difference between typical and atypical abilities was less than we might think (assuming we agree that he was human and not some other species), and thus might suggest that the evolutionary gap between chimps and humans is less hard to bridge than we'd intuitively guess. I certainly can't see how the existence of a dramatic difference between different humans argues for a difference in kind between humans and non-human animals!
Dembski also complains that the fossil record is consistent with an evolutionary explanation but does not absolutely require it. Fair enough--evolution is always an inference unless you are observing it directly, and obviously a species cannot observe and record their own pre-sapient evolution. He asks for "independent evidence", though, without giving any idea of what shape such evidence could possibly take. How about the fact that neutral mutation sites are more widely diverged between human and, say, gibbon, than human and chimp, and this trend is observed across the genome? That certainly is a powerful argument that humans and chimps shared a common ancestor more recently than humans and gibbons did--or that a creator tried really, really hard to make it look as though that was the case.
For gene expression data in human and chimp brains that also supports the similarity between chimps and humans (arguing for a recent common ancestor), see the article by Uddin et al. in PNAS 101:2957 (2004) showing that anterior cingulate gene expression profiles in chimps were closer to those of humans than to those of gorillas (or macaques).
Dembski also spends far too much effort talking about an old and rough estimate of 98% similarity between chimp and human DNA sequences. We have the genomes of both species now; let's revisit the issue when that analysis is ready. However, there is one conceptual error that is worth addressing.
quote:
The holistic nature of the gene expression system means that minor changes are likely to produce a disconnected mess rather than a coherent, interwoven whole. And it is these vastly different, coherent, interwoven wholes that constitute the gene networks that differ in the brains of humans and chimpanzees.
The assumption here is that the two are vastly different and interwoven vastly differently. However, vast differences in expression patterns can be observed as a consequence of just one mutation in a transcription factor (expression profiling studies exactly this phenomenon), so the observation of a large difference in quantities of proteins can be explained by a relatively small number of genetic changes. Thus, the 31% quantitative difference vs. 7% qualitative difference argues that this is exactly what's going on.
There is a further point about DNA similarity that Dembksi doesn't address but ought to. There is evidence of higher rates of mutation in nonsynonymous sites vs. synonymous sites between chimps and humans in genes relating to brain function. This is precisely the signature expected to be left by positive selection in an evolutionary framework. See, for instance, Evans et al., Human Mol. Genetics 13:489 (2004).
The section on language points out that humans have vastly richer and more flexible linguistic capabilities than chimps. But humans with various mental deficits show a wide range of linguistic abilities, with some only approximately sophisticated as a chimpanzee--so I don't see the crisp and compelling break between human and chimp. I am delighted with the power of the human linguistic system, but unlike Dembski, I don't think it degrades our ability to notice in what manner our abilities are similar to those of other animals.
Dembski mentions that "[Ruse and Wilson's] evolutionary view of morality cannot be squared with the facts of our moral life." Unfortunately, I can't pinpoint the supposed failure to comport. Dembski raises some possible alternative explanations, and doesn't show why those fail or are logically unsound. He claims of these explanations that, "Certainly, they denigrate our moral sensibilities." But this is no reason why they are untrue--merely unpalatable to some.
The criticisms of the lack of ideas on what pressures and mechanisms led to larger human brains is, as far as I know, largely warranted. But this isn't really evidence against human evolution so much as it is a lack of evidence for it, unless there is good reason to suspect that we ought to have a clear indications of the relevant pressures and mechanisms.
In terms of the evolution of mathematical ability, I will gladly grant that we don't have a good idea of the adaptive value of that either. However, there is a possibility that Dembksi hasn't considered--mathematical ability is a byproduct of our role as toolmakers. As I recall, IQ, mathematical ability, and inventive problem-solving are all fairly strongly correlated positively. And I have personaly observed that people with expertise building mechanical systems (e.g. those with training in a machine shop) have superior abstract thinking skills (in this case, in genetics). Tools are a major reason why humans are so successful, and complex abstract thinking skills are needed to match up the problem at hand with materials available to create appropriate tools. In a sense, this is a byproduct hypothesis, as mathematics is just another abstraction that (some of us) can put our generic abstract-thinking ability to work on. But I'd argue that it was tool-making, plan-making, coordination, and flexible thinking to overcome dangerous conditions that provided the evolutionary drive towards sophisticated abilities for abstract thought.
Dembski wonders why there wasn't a stronger pressure for small brains. I'd suggest it was because there wasn't time. Making a tissue larger to improve its function is easy; just upregulate a few transcription factors and growth hormones and, thanks to the distributed nature of cognition, you have increased capability. Sophisticated reworkings of existing brain structures would likely take much longer to evolve.
Also in this section, Dembski mentions a couple of cases where fairly major altertions in brain morphology produced surprisingly small behavioral effects. He then makes the statement
quote:
The materialist assumption, entertained by many evolutionists, that mind is reducible to brain remains for now without any empirical support. What we have are correlations between brain images and conscious mental states. What we do not have is a causal mechanism relating the two. Quite the contrary, there are now good reasons for thinking that no such causal mechanism exists and that mind is inherently irreducible to brain.[19]
Dembski vastly understates the case for a material basis for cognition. While it is true that we are nowhere near having a complete (or even fragmentory) causal picture of how the brain works and how/if those workings relate to mental states, we nonetheless have a vast body of evidence that mental states are the product of the neurophysiology of the brain. There are five powerful, independent lines of evidence. First, there are a vast array of largely predictable cognitive defects that occur when various portions of the brain are damaged. Second, subjects who are asked to perform similar cognitive tasks usually show increased activity in portions of the brain specific for those tasks--and these regions of activity are usually in areas that, when damaged, result in a deficit in performance on that task. Third, electrical or magnetic stimulation of the brain can evoke a variety of sensations and feelings--and effects elicited by a given site match both the defects and the functional activity. Fourth, neuroactive drugs have profound (and in some cases, somewhat understandable) impacts on cognitive function. Fifth, animal studies show architectural changes to brains in response to learning and memorization tasks, and drugs or other manipulations that block the structural changes also block the learning and memorization.
With multiple demonstrations that brain is necessary and sufficient for mind, there is very, very little room left for mind that is irreducible to brain.
I don't personally find this troubling. That my mind isn't reducible to my brain doesn't negate the fact that I do have a mind. I am implementation-agnostic: whether mind is disembodied or physical, the important thing to me is that I have one. And anyway, the universe is unlikely to change whether my mind is disembodied or physical on the basis of whether I feel troubled by one option or the other.
In conclusion, in its current state, Reflections on Human Origins may be a comforting tract to committed antievolutionists, but due to a variety of poorly argued points, omissions, and under/overstatements, it's unlikely to convince anyone who is not already convinced that humans did not evolve, and provides little shelter for those are convinced against arguments from those who are not.
[ 09. July 2004, 15:00: Message edited by: Rex Kerr ]
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Mark Elkington
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posted 19. July 2004 09:12
William Dembski quotes some interesting data on brain protein, "around a 7 percent qualitative difference; nevertheless, the quantitative difference in this case was over four times higher than expected, namely, 31 percent."
Without quibbling too much over the exact genome overlap, human/chimp commonality based on this data is:
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genotype 95-98%
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v
phenotype 69-93%
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sociotype less than 1%?
Shown are a progression of layers, each an expression of the previous: a revelation of the inbuilt functional potential of the previous layer. Small changes translate to large differences in the succeeding layer, as expected with a complex, nonlinear system and mapping.
Defining "sociotype" as individual and collective abilities and achievements over time, subjectively humans vastly exceed chimpanzees (hence the tentative estimate of less than 1%). What comparison is there between spaceflight and the contemplation of consciousness with the scratchings of apes?
However, the slow, gradual, cumulative nature of human knowledge aquisition and application (i.e. building/evolving the collective sociotype) must be considered--a kind of "compound interest" effect over several millennia which arguably invalidates such a comparison. On the other hand, this ability could itself be taken as evidence of an intrinsically large functional difference. Moreover, does the philosophy of Plato or Socrates, for example, represent a significantly original, non-derivative work, thus sidestepping the problem of accumulation?
Dembski discusses language and intelligence as categories for sociotype differentiation. I was surprised by his use of the example of William Sidis, for reasons similar to those given by Rex Kerr. The captive gorilla Koko is claimed to have "a working vocabulary of over 1000 signs. Koko understands approximately 2,000 words of spoken English...a tested IQ of between 70 and 95 on a human scale." (Koko) This transcript of one of Koko's "conversations" makes it easy to see why these claims have been disputed. (More rigorous references to estimates of animal intelligence welcome.) All the same, is the IQ difference between Sidis (250-300) and average (100) larger than the difference between the average human and Koko? Sidis apparently knew all 200 human languages, and could learn a new language in one day. I wonder how the language ability of least able humans (without disability) compares with that of outstanding primates? (A Larson cartoon featuring a frustrated and ostracised gorilla wearing glasses pops into the imagination).
If human/chimp intraspecies differences in language and intelligence exceed interspecies averages, this is disconfirming of the need for large, fundamental, quantum underlying differences in human/ape biology, design, and origins.
This whole discussion highlights again a basic issue for ID: quantifying functional complexity.
A lack of objectivity may incline us to overstate our own species' superiority. Equally, ostensibly near-identical human/chimp genomes and morphology could lead to prematurely concluding noninterventionist incremental evolution as the best model, and missing the real and profound differences concealed within these similarities.
As a designer in the engineering field, I can vouch for generally a nonlinear relationship between function and complexity: double the functionality and you will need to quadruple the complexity. But can a free lunch of functional complexity be had from a chance tweak to an existing complex neural network? In Sidis' case, possibly yes. If so, why not similarly for ape to human brain evolution? To argue against this is to imply that Sidis was not exceptional, but rather most of us in fact have limited access to the full potential of our brains due to the right switches not being thrown during otherwise normal development. That is, relative to the designed-in potential, a large majority of people have significant to severe mental disability. The question of whether this represents a degraded design, or the designer's intent was only occasional near-complete realisation of this potential is perhaps more theological than scientific.
Mark
[ 19. July 2004, 09:49: Message edited by: Mark Elkington ]
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