Is the flagellum specified?

If the complexity of the bacterial flagellum-where complexity is defined by Dembski's own unorthodox criterion-has not been successfully demonstrated, then the matter of its specification could, perhaps, be set aside as no longer relevant.  Nonetheless, let us look at Dembski's development of this portion of his argument for the specified complexity of the flagellum.

In several places in No Free Lunch, Dembski goes to considerable lengths to state the requirements that specification and detachability must satisfy in the careful language of logic, set theory and the like.  The index of the book cites more than 40 pages dealing with the topics of "specification" and "detachability," plus approximately 100 page-citations for closely related topics such as "specifiability," "specificational resources," "biological specificity," and "specified complexity."

However, when it comes time for Dembski to support his conviction that the bacterial flagellum is specified, the procedure becomes considerably more casual, almost facile.  Speaking on the specification of biological systems in general, Dembski simply asserts that, "Biological specification always refers to function.  An organism is a functional system comprising many functional subsystems.  In virtue of their function, these systems embody patterns that are objectively given and can be identified independently of the systems that embody them.  Hence these systems are specified in the sense required by the complexity-specification criterion."[47]  In these four brief sentences the foundation of Dembski's entire strategy for certifying the specification of biotic systems is laid.

Addressing the particular question regarding whether the bacterial flagellum is specified, Dembski confidently declares that, "Specification is never a problem.  The irreducibly complex systems we consider, particularly in biology, always satisfy independently given functional requirements...For instance, in the case of the bacterial flagellum, humans developed outboard rotary motors well before they figured out that the flagellum was such a machine."[48]  The flagellum functions like an outboard rotary motor.  The rotary outboard motor pattern represents a functional requirement independent of biological systems.  Therefore, concludes Dembski, the flagellum is specified.

This use of a human contrivance like the outboard motor as the independent, detachable pattern that certifies the flagellum as being specified bears further scrutiny.  Following the quotation above, Dembski continues:  "This is not to say that for the biological function of a system to constitute a specification humans must have independently invented a system that performs the same function.  Nevertheless, independent invention makes the detachability of a pattern from an event or object all the more stark.  At any rate, no biologist I know questions whether the functional systems that arise in biology are specified."[49]

"Specified" in the same technical sense defined by Dembski?  Specified by exhibiting an object/event-independent pattern?  Not necessarily.  We need to look closely at the way in which Dembski first introduced the concepts of specification and detachability.  "For a pattern to count as a specification, the important thing is...whether in a certain well-defined sense it is independent of the event it describes.  Drawing a target around an arrow already embedded in a wall is not independent of the arrow's trajectory."[50]  Patterns that satisfy this condition of independence are designated as detachable.  To determine if some particular pattern is detachable, the following question must be answered affirmatively, says Dembski:  "Given an event whose design is in question and a pattern describing it, would we be able to explicitly identify or exhibit that pattern if we had no knowledge of which event occurred?"[51]

To illustrate this test, Dembski uses the "event" of coin-flipping and looks at numerical patterns that might be generated by the sequence of heads and tails transcribed into strings of 0's and 1's.  If a string corresponding to the first 100 digits written in binary form appeared, we would be warranted in believing that the sequence did indeed conform to a detachable pattern.  That numerical pattern could easily be identified independently of the event of coin flipping that generated it.

However, to move from Dembski's pattern illustrations involving sequences of numbers or alphabetical letters (as in a sentence of words) to biological systems requires, I believe, far more than a hand-waving reference to biological functions playing the role of detachable pattern.  On what basis can Dembski assert, for instance, that "Biological specification always refers to function"?  Is this any different from "drawing a target (representing some particular biological function) around an arrow already embedded in a wall (representing a functioning organism)"?  What is the specific function of the flagellum that warrants being counted as a detachable specification pattern? Its function as a means of locomotion?  Apparently not.  If that were the case, would we not find ID books filled with claims that all animals equipped with any means of locomotion were intelligently designed?

So, then, do only rotary motor systems count as biological propulsion systems exhibiting a detachable pattern in their function?  On what basis would other propulsion systems be disqualified?  How narrowly does Dembski define biological function?  And where does he develop a system for determining that some functions count toward specification and others do not?  If it really is the case that, as Dembski states, "Biological specification always refers to function," wouldn't all biological functions then count as detachable patterns exhibited by biological systems?

Apparently not.  Recall that, by Dembski's measure, a bacterium without a flagellum does not exhibit an instance of specified complexity.  For reasons that are not explained, of all the remarkable biological functions in which the bacterium-sans-flagellum participates, none appears to satisfy Dembski's criterion of specification.  On what basis is the function of the flagellum singled out as the only bacterial function that is sufficiently spectacular as to require the assistance of an unembodied intelligent designer to actualize?

However, perhaps there is another approach that deserves investigation.  In our reflections on the question, Is the flagellum complex? we argued that the focus of attention should be shifted from the flagellum structure itself to the portion of the E. coli genome that coded for its development.  If that is correct, as it must be, then our search for a detachable pattern should be directed toward the base pair sequence in E. coli's circular DNA molecule.  Surely there is an identifiable pattern there that characterizes the genetic coding for the flagellum, right?  Right, but the crucial question is, Is that pattern detachable from the event under consideration, E. coli develops a flagellum?

I believe the answer must be a resounding, No.  The pattern in the base-pair sequence associated with this flagellum-actualization event is unique to that event and to that event alone.  This pattern is the epitome of non-detachability.  The pattern and the event are not independent, but stand in a one-to-one relationship.  The base pair sequence pattern is like a blueprint for the flagellum.  The pattern in question is not detachable, and the flagellum is not specified in the particular sense required by Dembski's complexity-specification criterion.

Bacterial Flagella and Dembski's Case for Intelligent Design:  Closing Arguments

Earlier in this critique we outlined Dembski's case for the proposition-bacterial flagella are intelligently designed-as follows:

1) The bacterial flagellum displays specified complexity.

2) Specified complexity in biotic systems cannot be generated by the Darwinian mechanism, which relies on chance.

3) Therefore the bacterial flagellum must have been intelligently designed-that is, it could have been actualized only with the assistance of form-conferring interventions by an unembodied intelligent agent.

We then focused our attention on the first of these statements and asked, Does the bacterial flagellum exhibit "specified complexity" as it is defined by Dembski?

In order to do that it would have to be a) sufficiently complex, and b) specified.

Is the bacterial flagellum sufficiently complex?  Using Dembski's own criterion, only if the probability of its being actualized by the joint action of all natural causes is less than the universal probability bound.  Dembski attempted to demonstrate this to be true by treating the bacterial flagellum as if it were a discrete combinatorial object actualized by the pure chance gathering of 50 of the right kinds of proteins (and in the correct proportions) at some spot in the vicinity of the cell wall and plasma membrane of E. coli and then, again by chance, happening to configure themselves into a functioning rotary propulsion system for this bacterial cell.  The only natural formational process that Dembski considered in his probability computation was self-assembly by pure happenstance.

We reject that argument as being a totally unrealistic caricature of how the flagellum is actualized and an approach that totally ignores the role of the bacterial genome in coding for all of the structures and functions that contribute to the nature of E. coli.  Furthermore, if, as Dembski himself states, a bacterium without a flagellum does not exhibit specified complexity, then the addition of a flagellum could be accomplished in whatever non-designed way (that is, without need for non-natural intervention) that the rest of the bacterium (which includes structures remarkably similar to parts of the flagellum) came to be actualized.  If the actualization by natural causes of an entire cell (without a flagellum) is not sufficiently difficult to qualify the cell as complex by Dembski's standards, then neither is the addition of a flagellum.  Dembski's case for the complexity (as he defines it) of the bacterial flagellum fails.

Is the bacterial flagellum specified?  Using Dembski's own criterion, only if it exhibits a pattern that is detachable-wholly independent of the event that produced it.  Appearing to set aside his laboriously crafted formalism regarding the specification and detachability requirements, Dembski simply asserts that in the case of biological systems specification always refers to function, and declares that biological functions are inherently detachable from the particular biological systems that instantiate them.

We reject that argument for a number of reasons.  First, the general principle that biological function counts for specification was never established by Dembski.  Second, his application of this principle appears to be entirely ad hoc.  Dembski provides no systematic means for concluding that the function of the flagellum should count as a detachable specification while other equally remarkable biological functions of E. coli fail to qualify.  For instance, if none of the functions of a bacterium-sans-flagellum qualify the bacterium as being specified, then there appears to be no basis for counting the function of the flagellum any differently.  If none of the other biological functions of the bacterium count as a detachable specification, then neither should the function of the flagellum.  Dembski's case for the specification (as he defines it) of the flagellum fails.

Finally, there is the broad question concerning Dembski's rhetorical use of key terms like complexity and specification.  On the question of specification, for instance, Dembski asserts that, "no biologist I know questions whether the functional systems that arise in biology are specified."[52]  The question is, however, Is Dembski using the term "specified" in the same way as the biologists he has in mind?  The answer, I believe, is, No.  Dembski treats the presence of biological function as if it constituted a detachable pattern independent of the organism under scrutiny.  For Dembski, biological function is one of the qualities of a complex organism that only intelligent intervention could produce.  For biology, on the other hand, biological function plays nearly the opposite role.  It is the very capacity of an organism that gives it the ability to respond to its environment in the manner described by a fitness function, a phenomenon that lies at the heart of evolutionary dynamics.

A similar concern about Dembski's use of key terms arises in regard to the meaning of "complexity."  After quoting a number of prominent biologists regarding the scientific challenge of accounting for the information now resident in complex biological systems, Dembski asks, "But what sort of information are they talking about?"[53]  He soon answers his question in a way that appears to place their concern squarely in his own design-theoretic court. "I submit that what they have in mind is specified complexity, or what equivalently we have been calling...complex specified information.  Certainly the complexity of biological information is not at issue."[54]  But of course this bold assertion could be true only if Dembski is using the term "complexity" in the same way as the persons he quoted, which seems not to be the case.  As we saw in our general considerations on complexity, the "complexity" that Dembski computes is a property, not of some biotic system itself, but of the means by which it becomes actualized.  That is why, for instance, he treated the bacterial flagellum as if it were a discrete combinatorial object and judged its complexity on the basis of the probability of its coming to be actualized by pure chance alone.  Most biologists, on the other hand, use the term "complexity" as the name of something quite different-a structural or functional quality of the biotic system itself.

But "specification" and "complexity" are not the only terms that Dembski, like other leaders of the ID movement, employs rhetorically with unorthodox meanings.  Recall, for instance, that to be "intelligently designed" is, in effect, to be assembled with the aid of form-conferring (or information-infusing) action performed by an unnamed and unembodied choice-making agent.  Recall also that when this unembodied intelligent agent brings about a naturally impossible outcome, it is not a "miracle."  And recall that "chance hypothesis" most often means all hypotheses, postulates and theories concerning the natural causation of events.  The case for ID relies on a web of words that have been assigned extraordinarily unusual meanings.

Given this character trait of ID literature, including such works as Dembski's No Free Lunch, would it not be appropriate to suggest that Dembski pause to reflect on his own admonition regarding the need to use words appropriately, consistently, and with precision to avoid the charge of equivocation?  Says Dembski, "The fallacy of equivocation is the fallacy of speaking out of both sides of your mouth. It is the deliberate confusing of two senses of a term, using the sense that's convenient to one's agenda."[55]  I agree.  Ironically, however, I find Dembski's rhetoric to be riddled with the very equivocation that he condemns.

NOTES:

47 No Free Lunch, p. 148.

48 NFL, p. 289.

49 NFL, p. 289.

50 NFL, p. 15.

51 NFL, p. 15.

52 NFL, p. 289.

53 NFL, p. 148.

54 NFL, p. 148.

55 William A. Dembski, Intelligent Design: The Bridge Between Science &Theology (Downers grove, IL: InterVarsity Press, 1999), p. 115.