Occam's Hammer: Creationist Rhetoric and the Myth of Philosophical Naturalism

By Connor J. O’Brien

As we are all aware, the recent publicity surrounding the Kansas Kangaroo Kourt and the Dover, PA case has led many academics outside of the biological sciences to weigh in on the place of Creationist ideas like Intelligent Design in the scientific discourse. The rhetoric of these missives will be familiar to anyone who’s paid attention to creationist attacks on the theory of evolution over the years. In short, there’s nothing new here, but I think one particular element of the specious reasoning often employed calls for a thorough analysis. The following quotations are just a small, representitive sample.

As a mere armchair philosopher with no qualifications in the sciences, I’ll let Andy C. McIntosh, Professor of Thermodynamics and Combustion Theory at the University of Leeds start:

A growing number of academics on both sides of the Atlantic are attracted to the straightforward logic of scientific reasoning.

The logical, coded machinery of DNA and the information system it carries shout design to an unprejudiced mind.

Letter in the London Times

Note the emphasis on “unprejudiced,” “straightforward logic.” With no stated qualifications in biology, the good professor would like us to take his word on the strength of his dispassionate intellect as it shines the cold light of reason on the controversy.

And here, from Theologian John Warwick Montgomery, we have the argument made in its purest form:

And what has happened to Occam’s razor—the fundamental scientific principle that, faced with two plausible explanations of the same phenomena, one should choose the simplest? Are Michael Behe, William Dembski, and the others dismissed by Orr perhaps doing better science than he when they argue that “if it looks, walks, and quacks like a duck, then, absent compelling evidence to the contrary, we have warrant to conclude it’s a duck. Design should not be overlooked simply because it’s so obvious.”

An unpublished letter to the New Yorker

A blunt instrument indeed to use in Occam’s name. For the sake of argument, I’m going to pass over “two plausible explanations” and get to the heart of what is so badly flawed here. Occam’s razor, commonly known as the principle of parsimony, is most often rendered, from the Latin, as “Entities should not be multiplied beyond necessity.” It is indeed a “fundamental scientific principle,” but Montgomery seems to advocate it as a method of determining the truth independently of any further empirical research. This would be fine, were he a contemporary of Occam and Aquinas, saddled with Aristotle as the received authority on empirical matters and lacking a method for further inquiry. But we now have such a method, which makes good use of the principle in the often overlooked, but decidedly non-trivial, process of selecting for consideration testable hypotheses upon which to perform further investigation. In terms of modern science, Montgomery’s appeal to parsimony badly abuses the notion of what we are prepared to consider a “simple” explanation.

Parsimony means we choose, for consideration, the hypothesis that asks us to make the fewest–and least unsupported–assumptions. Like most fundamental logic, the principle is a refinement of everyday reasoning, easily demonstrated to be “just common sense.” And so a short example may clarify matters. (Note that this is meant as an illustration only, and in no way bears the weight of the argument.) Say I am in my house, and I can’t find my keys. I entered some time ago, using the keys to get in, so I have every reason to believe they’re in the house somewhere. The answer to the question “where to look?” can be seen as the hypothesis I will test to try to determine the whereabouts of the keys. Now, a perfectly “simple” explanation might be: a malevolent fairy took the keys. Parsimony rejects it, though, not because we “know” there is no such thing as fairies, or because we have an ideological commitment to their non-existance, but simply because the existence of fairies is not a well-supported assumption. Alternatively, we may conclude that a burglar entered the house and made off with the keys. Burglars do, in fact, exist, but the assumptions entailed are that an individual with the means to break into my house was in the neighborhood and was motivated to enter my home just to steal my keys. Possible, but not well supported by prior experience. So, the parsimonious hypothesis is that I misplaced my keys and I should search my house. The pragmatic advantages of this reasoning are obvious: our search (research program) is constrained to an easily searchable area. In the fairy hypothesis, our search is utterly unconstrained (Iceland? The Faery Realm?), in the burglar hypothesis, our search is constrained, but only to the area in which the burglar could conceivably have travelled in the intervening time, several square miles, let’s say, and growing.

Since there are not, and are not ever likely to be, any details whatsoever about the mysterious creator/designer, we can see that his/her/its assumption is the very sort of thing that the principle of parsimony leads us to reject out of hand. As it can be offered as the explanation for absolutely anything, if we did not tacitly reject it from working hypotheses, we would have to empirically reject it first, and no scientific experiment would ever have been performed. (In the example of the keys, Creationism requires us to contemplate the Faery Realm before we’ve even started searching the house.)

Now, while I am irked to see a basic principle of logic abused in this way, and there is some satisfaction to be gained from “setting the record straight,” that in itself would not have been sufficient to prompt the current discussion. I think there may be more here than restoring the edge to Occam’s Razor.

Note that, as applied to scientific hypotheses, the principle is purely methodological. We use parsimony to constrain working hypotheses to the set of “probably testable” hypotheses. We are always free to return to the beginning and revise our stance on what constitutes a well-supported assumption. (If we conduct a truly exhaustive search, and still can’t find the keys, or, in searching, we discover that many other items are missing, the burglar hypothesis may gain support.) Since we are merely looking for a testable idea on which to do empirical research, we have specifically not committed ourselves to any position whatsoever. It is also important to emphasize that, by specifically concentrating on underlying assumptions, we avoid the purely pragmatic, but futile, method of “looking where the light is best” even when we know that what we seek is likely not there. This is exacly why parsimony is such a wonderful tool: it allows us to prefer pragmatic hypotheses without succumbing to methodological tunnel vision. With these points in mind, we can now appreciate that a crucial element of the legal/rhetorical argument put forth in favor of allowing creationist ideas into the science classroom has it exactly backward.

The creationist claim is that, while their ideas may be religious in nature, that should not count against them, because, due to its prior commitment to “Philosophical Naturalism” (equated with Atheism), the Theory of Evolution is a religious idea too. Setting aside the general incoherence of this as a legal strategy, we can see that Occam’s Razor, when sharpened and used properly, cuts right through the central claim. For is not “naturalism” simply one implication of parsimonious reasoning applied to the selection of hypotheses for consideration? After all, the same reasoning will eliminate a great number of hypotheses that ask us to make perfectly “natural,” but poorly supported, assumptions, as well as “supernatural” assumptions. Since the principle of parsimony is evidently fully acceptable (at least in name) to self-styled clear thinkers regardless of commitments to Theism or Atheism or any other postion, the claim that, in this one instance, its application amounts to a full-blown philosophical commitment is simply untenable.

In conclusion: There is nothing earth-shattering here. The poverty of general, logical objections to the theory of evolution is well understood by the regulars at The Panda’s Thumb. My aim has been, on one hand, to clearly highlight the misleading appeal to logic I’ve called Occam’s Hammer, and on the other, to show how the creationists have indeed landed a blow with that dubious instrument, but, sadly, it came down just slightly to the left of the nail, and squarely on their thumb.

Connor J. O’Brien is Textbook Manager at Ned’s Bookstore in Berkeley, California. He has studied philosophy and literature and maintains an active interest in the philosophy of science and evolutionary theory.