Dr. Shallit Replies - Evolution News & Views

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Dr. Shallit Replies

Dr. Jeffrey Shallit has answered my question about the analogy between S.E.T.I. research and the inference to intelligent design in biology. His reply was thoughtful, made some good points, and was free of personal insults.

My question was:

"If the scientific discovery of a 'blueprint' would justify the design inference, then why is it unreasonable to infer that the genetic code was designed?"

Starting off, Dr. Shallit demurs:

One thing I'd like to point out is that Egnor seems to be under the misapprehension that the information theory that mathematicians and computer scientists actually study has something to do with inferring design.* This is simply not the case....as a mathematician and computer scientist I have no particular expertise on the general topic of "inferring design". It's just not something we do; maybe he should ask a SETI researcher, or a forensic investigator. But then again, Egnor has no particular expertise on the topic, either.

That's not true -- about either of us. All of us discern design as a matter of daily life. It's an essential expertise. For scientists -- all scientists -- it's a particular expertise. For some scientists -- forensic scientists, cryptographers, archaeologists -- discernment of design is their science. For other scientists, discernment of design makes their science possible. Physicists discard data tainted by artifact from their own instruments. Astronomers distinguish natural from artificial signals -- pace Penzias and Wilson, who, by distinguishing natural signals from artifact in their own equipment, discovered the background radiation from the Big Bang. Chemists must distinguish synthesized compounds from contaminants. Computer scientists -- like Dr. Shallit -- must distinguish signal from noise.

Biologists routinely use the design inference in their work. Recombinant DNA research is impossible unless one can reliably distinguish between humanly designed and natural organisms. Ecologists distinguish natural environmental changes from changes that are the result of human intervention. The debate over global warming turns on this ability to distinguish natural temperature change from man-made temperature change. Even evolutionary biologists -- especially evolutionary biologists -- use the design inference. Natural selection must be distinguished from artificial selection -- it is the exclusion of design that forms the basis of Darwin's theory of random mutation and natural selection.

Surely Dr. Shallit didn't mean that the discernment of design is irrelevant to science, or that none of us are any good at it. We're remarkably good at it. Without the design inference, science (and daily life) would be impossible. The pervasive inability to discern design in science would preclude science. The pervasive inability to discern design in ordinary life is autism.

Perhaps Dr. Shallit meant that we aren't good at quantifying design. But that's not true either. Design is quantified in different ways in different scientific disciplines, but quantification of design is essential to most sciences. It's essential to forensic science ("Doctor, is the angle from which that bullet was fired more consistent with accident or with homicide?"), to physics ("The vibrations in the crystal are at 50 Hz., and are therefore artifact from vibrating equipment in the lab"), and to molecular biology ("The organisms with the new gene will make at least 70% more of the protein than the unaltered organisms"). Quantification of designed artifacts, using various methods, is routine in science.

So what did Dr. Shallit mean? He explains:

Elsberry and Wilkins point out in their article from Biology and Philosophy, there is a huge difference between inferring design based on artifacts for which we have a causal story like human construction, and inferring design based on some causal story lacking any details whatsoever. They refer to this latter attempt, commonly used by ID advocates, as "rarefied design", and characterize it as "based on an inference from ignorance, both of the possible causes of regularities [that might explain the event] and of the nature of the designer."

So rarified design -- design without a detailed casual story -- troubles Dr. Shallit. He continues with the example of "skirnobs":

The problem with a simple conclusion that something is designed, is its lack of informativeness. If you tell me that skirnobs are designed but nothing else about them, then how much do I actually know about skirnobs? Of a single skirnob, what can I say? Unless I already know a fair bit about the aims and intentions of skirnob designers, nothing is added to my knowledge of skirnobs by saying that it is designed. I do not know if a skirnob is a good skirnob, fulfilling the design criteria for skirnobs, or not. I do not know how typical that skirnob is of skirnobs in general, or what any of the properties of skirnobs are. I may as well say that skirnobs are "gzorply muffnordled", for all it tells me. But if I know the nature of the designer, or of the class of things the designer is a member of, then I know something about skirnobs, and I can make some inductive generalizations to the properties of other skirnobs.

Is the inference to rarified design really uninformative? Knowing whether skirnobs are designed is the most informative thing we could know about them: knowing whether they are designed determines the way we study them. Imagine a scientist who knew nothing of literature or of the origin of language (but he could understand and use language of course). Imagine that he found a stained flexible wood slice with the marking "skirnob" on the front, and the following marks on the back:


That time of year thou mayst in me behold
When yellow leaves, or none, or few, do hang
Upon those boughs which shake against the cold,
Bare ruined choirs where late the sweet birds sang.


Does it matter to the rarified design scientist if the stained-wood-slice-skirnob is designed or not? Of course it does. If the skirnob isn't designed, the scientist can completely understand the skirnob by studying the relevant laws and chances that gave rise to it (the chemistry and surface adherence of pigments, the tensile strength of the wood-slice, etc). If the scientist incorrectly infers design, he would make a futile attempt to assign meaning to the stains. In assigning meaning by falsely inferring design, he would misunderstand the skirnob.

If the skirnob is designed, the scientist can completely understand the skirnob only by studying the teleology -- the purpose -- of the artifact, as well as the laws and chance that played a role in its emergence. The scientist would discover that the stains, in addition to abiding by the laws of chemistry and physics, conveyed meaning -- in this case, the lament of an aging poet (Shakespeare, in his 73rd sonnet).

The correct inference to design -- rarified or mundane -- is essential to an understanding of a phenomenon, because it determines how we study it. The distinction between a natural object and a designed artifact matters. We might melt down an asteroid to understand its composition. We wouldn't melt down a spacecraft to understand it.

Dr. Shallit continues:

I don't think that the question "is it designed?", in the absence of any candidate for a designer, is particularly interesting. That is, in the absence of motive, I don't think that knowing that something is designed tells you anything at all.

Is design in the absence of any candidate for a designer really uninteresting? Imagine coming home from work and finding a note on the table, in your wife's handwriting: "I love you." It's a wonderful note, but not particularly interesting, because you know who wrote it and how and why it was written. The sentiment is wonderful, but the note is mundane. Now imagine that you find a note, written in unfamiliar handwriting, taped to your car: "I love you." You don't know the author, and you have no casual history for the note, except that you surmise that the paramour is human, shy, and probably of the opposite sex. Most people (even scientists!) would agree that this note is a lot more interesting, precisely because its vintage is uncertain. The absence of a discernible casual history makes the design more tantalizing.

Now imagine that you are on the first manned mission to Mars. You land, and eagerly begin exploring the Red Planet (a boyhood dream of mine!). You find a machine with wheels and a scoop that looks like a little motorized vehicle, parked on the Martian sand. You investigate it, pleasantly surprised that you have come across an old Mars Rover. Mundane design, for sure (you know just how and why it was built and who built it), but pretty neat, nonetheless. You radio Houston Control and send a photo of the little buggy, wait the requisite several minutes, and receive your answer: "It's not ours. We have no idea where it came from." (!) Are you now more interested or less interested?

Dr. Shallit again:

I don't think that the question "is it designed?", in the absence of any candidate for a designer, is particularly interesting.

Most of us would think quite the opposite. Design without a casual history is less tractable, but it's inherently much more interesting than mundane design, precisely because it opens up new and often profound questions. Rarified design is, in the vernacular, a science-starter.

Dr. Shallit next makes a surprising admission:

As an example of something I'd find convincing, if we were to find a crashed spaceship with plans showing how to build a bacterium, and scientists carried out these plans and found that they really did construct life, then I'd find this very strong evidence that life on earth was designed.

We've not found a single spaceship, but a cynic might suggest that we found the plans, in Cambridge, in 1953. Perhaps the evidence for intelligent design is intrinsic, not extrinsic, to life.

Dr. Shallit goes on:

Finally, DNA doesn't carry any of the hallmarks of human design, the kind of design we are most familiar with... When we consider an analogy, like the one Egnor proposes, to be fair, we have to consider points of disanalogy, too.

No doubt there is disanalogy. The analogy between human design and biological design isn't perfect. There's no reason to expect that it would be -- the design in the genetic code is, after all, rarified design, not human design. Yet Dr. Shallit chooses odd examples of disanalogy:

Genes, for example, are often pleiotropic; they have multiple interacting effects. Human design, on the other hand tends to separate systems so they don't interact.

Human designs don't interact? What about electronic networks, assembly lines, feedback systems, and autopilots? What about integrated circuits? Surely Dr. Shallit occasionally opens computers and looks.

On S.E.T.I., Dr. Shallit continues:

The answer is that I don't think that these situations are at all comparable. In the case of SETI, the fact that we are receiving a narrow-band signal is already suggestive, since we don't currently know any simple physical process that could produce these signals. This isn't a definite conclusion, though, because we have no idea what the probability of intelligent beings is, and we can't rule out narrow-band signals arising from some other physical process we simply don't know about...Let's alter the Contact story. Suppose the signal didn't encode a machine, but rather a sequence of DNA bases S. When we create DNA corresponding to this sequence, and stick it in a cell, we get an organism that tells us all about life on some other planet. Now the analogy is even closer than before; yet I think it is clear that our inference about the origin of S is still different from any inference about our own DNA. Indeed, it is entirely reasonable and scientific to infer that S is designed by intelligent beings on another planet, but our own DNA evolved.

I disagree with Dr. Shallit's point, as best I understand it. A blueprint, encoded in a signal or in a genome, is evidence of design.

Next, Dr. Shallit makes the surprising assertion that ID advocates aren't sufficiently enthusiastic about identifying the designer:

... where's the designer? In SETI, we can pinpoint a place in the universe where the signals are originating from. If the signals encode a machine, we can reasonably deduce that the intention is that we are to build it. But in the genetic code, who is the hypothesized designer? Where did they originate? When did they carry out their design? What is the intention of the design? All the really interesting questions are ruled as 'out of bounds' by ID advocates. Until they really come to grips with these questions, they're doing religion, not science.

Biological design is rarified design. ID advocates don't speculate much about the identity of the designer or the designers because we're conservative. Perhaps some day we'll know a lot more. For now, we stick to scientific inferences based on data. I can understand Dr. Shallit's perplexity at our unwillingness to leap beyond the evidence and offer just-so stories. To a Darwinist, explanatory reticence seems peculiar.

So my reply to Dr. Shallit can be summarized:

1) All scientists use the inference to design in their work and all have particular expertise at doing so.
2) The inference to design is a testable inference in all disciplines of science. The methods of inferring design in science are often, but not always, quantitative, but the methods differ in different scientific disciplines.
3) Phenomena caused by law or chance can be understood completely by reference to law or chance.
4) Phenomena caused by design can be understood completely only by reference to law, chance, and teleology.
5) Therefore, the distinction between design causation and natural (law-chance) causation is essential in science; it determines the scientific approach appropriate to the study of the phenomenon.
6) Exclusion of the design inference from the study of a designed phenomenon necessarily leads to an incomplete understanding of the phenomenon, and attribution of design to the study of an un-designed phenomenon leads to an incorrect understanding of the phenomenon.
7) Rarified design (design without a casual history) is much more interesting, although scientifically less tractable, than mundane design (design with a casual history). A message from space is more interesting than a message from an acquaintance.
8) Several properties of living things, such as a blueprint/symbolic code (the genetic code) and integrated systems with parts that appear purposefully arranged (molecular nanotechnology), would be recognized as evidence for design in all fields of science -- except evolutionary biology.

So why do evolutionary biologists exclude the inference to design as an explanation for functional biological complexity? Why do they find the design inference in biology so uninteresting?

Could it have something to do with ideology?


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