Tuesday, December 13, 2005

Thoughts on the Intelligent Design Inference


One of the more psychologically powerful arguments against evolution by supporters of intelligent design and other creationist groups is based upon the so-called "design inference." Simply put, the idea is this: if one looks at a given organism, in certain respects, it resembles a machine in which the parts work together to perform some function. And just as we can look at a machine and infer that there was someone who either made or designed that watch, so we should be able to infer that there was an intelligence (God, or if we wish to be more vague, "the intelligent designer") who made the organism. As such, this is an argument from analogy.

Part I: Design and the Appearance of Design

For example, Young Earth Creationist Kent Hovind will often bring up the subject of his Casio watch. He will rattle off a list of its functions, which include storing 150 phone numbers, acting as a calculator, and performing the function of a countdown timer. Thus when he visited Japan, even though he never met the individual, he was "pretty sure" that there was someone in the country who had "made" the watch, then by analogy argue that the complexity of life could not have been the result of any natural process, but had to be created by God.

Likewise, he and other individuals who appeal to some form of the design inference would argue, if one takes a look at the eye, the heart, or the hand, these have the appearance of having been designed. For example, the eye has a lens with which to focus light, a retina which acts like film in receiving light, a mechanism exists for focusing on objects both near and far (in this case, muscles which adjust the shape of the lens), and the iris acts as a mechanism for adjusting the amount of light which the retina receives. So in various ways, the eye is comparable to a camera, albeit one that has developed as part of a living, growing organism, rather than being constructed by someone who makes cameras.

However, Michael Behe typically prefers to apply this argument at the molecular level:

"The resemblance of parts of life to engineered mechanisms like a watch is enormously stronger than what Reverend Paley imagined. In the past 50 years modern science has shown that the cell, the very foundation of life, is run by machines made of molecules. There are little molecular trucks in the cell to ferry supplies, little outboard motors to push a cell through liquid." (Michael Behe, "Design for Living," NYT February 7, 2005, Late Edition - Final, Section A , Page 21, Column 1)

But as many evolutionary scientists would argue, the appearance of design can be deceiving. For example, when Perceval Lowell looked through his telescope, he thought that he saw canals on Mars. And more recently, one photo of a rock formation on Mars looked almost unmistakably like a human face. Yet upon closer examination, the "canals" were simply geological patterns in the surface of Mars, and the apparent face on Mars looked nothing like a human face when viewed from another angle. In response to what Behe describes in terms of the internal workings of a cell, such scientists could easily argue that Behe is stretching the use of analogy well into the realm of metaphor.

For example, "trucks" do not walk around on two "legs," but this is precisely what myosin -- one of the transport mechanisms within the cell -- does -- while transporting intracellular supplies along suspended "fiber" highways of actin. Nevertheless, analogies between the artifacts of man and the organisms of nature seem warranted -- yet they immediately raise the questions of what sort of analogies should be drawn, and what sort of conclusions arguments from such analogies can properly support. Indeed, a better analogy for myosin would be that of workers carrying supplies while walking around under water on two legs, wearing magnetic boots which adhere to the suspended sidewalks they follow -- but I doubt that such an analogy would take us in quite the direction that Behe might want.

There are of course times when something clearly looks designed. To take an example which both Hovind and Behe are particularly found of, if someone looks at Mount Rushmore, even without knowing any of its history, one can "see" that it was designed. It in no way looks like it could have been the product of volcanism, plate tectonics, or erosion. It is a sculpture -- which was clearly made and designed by someone. But making this judgment in the absence of actual knowledge of its history, we would be relying upon our knowledge of other sculptures, statues, or wood carvings. We would be relying upon our knowledge of what humans are capable of doing, and would be able to suggest the means by which they did these things. This contrasts sharply with the so-called Intelligent Design theory which prefers to remain silent on the actual nature of their "Intelligent Designer" and the means by which he (it?) brought into being his designs. Yet this is exactly the sort of explanation that any scientific theory of "intelligent design" would be required to give.

Part II: A Division of Tasks

When Hovind cites Mount Rushmore as being analogous to a living organism in requiring someone to make it, there is already one problem simply in terms of Mount Rushmore itself: while it had a single designer, it did not have a single maker. There were teams of individuals who carved Mount Rushmore out of rock. There was a division of labor, albeit of a relatively simple sort. And if oblivious to this fact, one were to posit a single human maker, he could not be any ordinary human in possession of the technology which existed at the time. Either the technology being used by such a human would have had to be very advanced, or the human would have had to be some sort of superhuman -- with an extended lifespan or the ability to work very, very quickly. But this would be by no means the simplest solution which fits the facts: positing a team of sculptors using the technology available at the time (including dynamite) would -- and indeed, this is what we know to be the case, given historical records and personal accounts. Mount Rushmore is the product of a division of labor between ordinary human beings in possession of technology which was quite common place at the time of its construction.

There is another argument which both creationists and proponents of Intelligent Design will often make -- that expecting random evolution to arrive at a living organism or cell is like expecting a tornado ripping through a junkyard to produce a commercial passenger jet. But this argument is flawed on several levels. First, it omits any consideration of the actual pathways which produce proteins, cells, or living organisms. Second, it is an argument which assumes that evolution must finish its job in one miraculous fit of action, rather than performing things incrementally, over time. And third, while recognizing the role which evolution grants to random mutation, it completely ignores the role played by natural selection.

When mutations occur in living organisms, one should expect only those mutations which have little effect or a beneficial effect to get passed on to the next generation. And most genetic mutations have no effect. In omitting the role of natural selection, opponents of evolution set up a straw man who by design won't fight back. (Interestingly, when Behe tried to write an academic paper purporting to demonstrate the inadequacy of evolution, one of the first criticisms leveled against it by a peer was that it omitted the role of natural selection.)

Looking back at Kent Hovind's watch, he would be hard-pressed to find its maker. The problem is similar to that involving Mount Rushmore: just as there wasn't any one person who made Mount Rushmore, there wasn't any one individual who was responsible for creating Mr. Hovind's Casio watch. There was a division of physical labor, with some people being responsible for the shaping the metal which went into the casing, others being responsible for the glass, others being involved in the creation of the wires, and still others being involved in the creation of the silicon computer chip. Then there were the many groups of individuals responsible for mining and processing the raw materials which went into each of the components that ultimately went into the production of the watch. And along the way, there were many machines which were themselves the product of a great deal of physical labor and still other machines used to produce them. In the modern world, if one were to try and trace everything that went into making a single watch, the web of products, services, and people may very well extend out until it includes a significant fraction of the global economy itself.

But of course, there wasn't just a division of physical labor in the production of the watch, but a division of cognitive labor as well. There was the individual who designed the watch. There were individuals who knew how to run the machines and create the various components, and there were individuals who designed the components, and there were still other individuals who designed the machines. Thus when a Young Earth Creationist or proponent of Intelligent Design theory tries to argue for the divine creation of things in the biological realm by analogy with products created in a modern economy, if one follows the analogy through, it begins to lead in a direction which they would likely find undesirable.

For an individual to create a modern, industrially-manufactured watch, such an individual would have to have talents far in excess of those possessed by anyone alive today. Simply in terms of all of the knowledge which ultimately goes into design of the machines which are involved, such an individual would have to be a genius the likes of which this world has never seen. But even in the absence of anyone remotely fitting such a description, watches get made, for a modern economy breaks up the tasks which go into the creation and design of its products into manageable units and then assigns these tasks to people who are capable of performing them.

Part III: Running the Watch Backwards

One should also remember that the modern economy isn't something which simply sprang into being like Athena, fully-formed from the head of Zeus: the modern economy is the product of a long history of evolution, beginning with various primitive barter economies, then growing with the extension of trade, specialization, and innovation stretching across nearly ten thousand years of human civilization. At each point in which economic progress was made, the physical and cognitive labor was divided into manageable units, and there were individuals who were equal to the physical and cognitive tasks required of them at the time. Thus some people designed sundials and abacuses, later others designed mechanical watches and slide rules, and still later others designed early electronic watches and calculators, and along the way, many other needed technological improvements were made. Similarly, those who design or use the machines employed in the manufacture of various products must be viewed as largely products of their time and consequently of times past, having available knowledge accumulated over centuries. For example, those who design pieces of electronics are may very well be making use of algebra, calculus, principles of electrical engineering, chemistry, the theory of electromagnetism, and perhaps even quantum mechanics, where each of these fields no doubt had a great many contributions from a great many of other minds scattered throughout the centuries.

Now imagine that one were to gradually break-up the cognitive and physical labor even more finely in space and time. The tasks which people would have to perform would become increasingly dull and monotonous. But the more one broke up the tasks, the less that would be required, both physically and intellectually of the people performing the tasks, until at some point, no intelligence at all would be required anywhere within the economy at any point in its history. At some point, instinct might be enough, but breaking it up a little further, perhaps only autonomous functions. Breaking it up even further, all that would be required is simple trial-and-error, with errors getting eliminated by natural selection. Simple "innovations" which fail become dead-ends, and those which succeed live until the next minute or day. At this point, we have something which is in many ways quite analogous to the history of the evolution of life on earth -- with the main difference being that in the case of biological evolution, there is typically no distinction between the worker and the tools which the worker employs, and the central purpose of the worker's actions is not to earn money at some business, but to live until the next day, month, or year -- and ultimately reproduce.

There exists between many of the things which are the result of biological evolution in the natural world correspondences to things which are the result of technological evolution in the human world. An eye resembles a camera, and likewise, many of the mechanisms within an organism or cell often resemble machinery. These are cases of parallel evolution, much like dolphins and fish, birds and bats, or in the human world, the nearly simultaneous invention of the phone (by Alexander Graham Bell and Elisha Grey) or discovery of calculus (by Isaac Newton and Gottfried Wilhelm Leibniz), or the sonar employed by bats, dolphins, and submarines. In arriving at solutions to the problem of survival, nature is faced with many of the same sets of engineering problems faced by human engineers who design machines. And given the similar sets of problems and design constraints, one can often expect similar sorts of answers. Looking inside the cell, we see a kind of nanotechnology which is still several years or decades ahead of what we can accomplish. But given the design constraints, when our technology becomes more advanced in this area, we should see even more similarities between our nanotechnology and what nature has already achieved.

In Conclusion: The Design Inference -- Properly Understood

When someone argues by analogy that just as the complexity a watch implies a watchmaker, so the complexity of life implies either the existence of a god or more vaguely, an intelligent designer, there are many who will find such an argument fairly compelling. However, the analogy upon which this argument is based immediately breaks down for a number of reasons. First, we know that watches do not reproduce -- they are not biological organisms. But biological organisms do reproduce. Second, we know that humans exist, and that humans make these sorts of things. But we do not know that there exists anything which makes living organisms -- unless it is by means of reproduction. And if by "make," the individual who is putting forward the argument means something other than by means of reproduction, then his argument begins to look suspiciously circular.

However, there are even more problems with this argument once one begins to carefully examine how a watch is specifically made -- even before one gets to any kind of analogy. The analogy itself is intended not simply to argue for the existence of someone who made living organisms, but who is also exceedingly intelligent. But virtually any manufactured good, if created by a single individual, would imply an intelligence far greater than anyone who has ever lived. Nearly any manufactured good that one can think of is in one way or another the product of a division of physical and cognitive labor, and in this sense, is properly viewed as the creation of not one maker or designer, but of a long list of individuals stretching across the globe, and back to the dawn of civilization -- and even before that. And given this division of labor, while some of the individuals involved were undoubtedly geniuses, all of them were quite human. Moreover, one would in fact be hard-pressed to suggest a human artifact which is simple enough to have been designed by an individual without employing the division of physical and cognitive labor.

The complexity of a watch or other manufactured good which the arguer casually explains by reference to its maker or designer is itself the product of two fairly interdependent evolutionary processes: the growth of human technology and the growth of human knowledge. And just as a division of labor reduces the degree of intelligence required of anyone involved in the production of a manufactured good, so may a further division of labor reduce the degree of intelligence even more in the production of something exceedingly complex -- even to the point at which no intelligence would be required anywhere at all. Those who make use of the design inference to argue for an intelligent designer also seek to deny that the complexity of life can be explained by means of evolution, but when properly understood, their argument strongly suggests the very opposite is the case.


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