Many, many people seem to misunderstand the relationship between Intelligent Design and Common Descent. Some view ID as being equivalent to Progressive Creationism (sometimes called Old-Earth Creationism), others seeing it as being equivalent to Young-Earth Creationism. I have argued before that the core of ID is not about a specific theory of origins. In fact, many ID’ers hold a variety of views including Progressive Creationism and Young-Earth Creationism.
But another category that is often overlooked are those who hold to both ID and Common Descent, where the descent was purely naturalistic. This view is often considered inconsistent. My goal is to show how this is a consistent proposition.
I should start by noting that I do not myself hold to the Common Descent proposition. Nonetheless, I think that the relationship of ID to Common Descent has been misunderstood enough as to warrant some defense.
The issue is that most people understand common descent entirely from a Darwinian perspective. That is, they assume that the notion of natural selection and gradualism follow along closely to the notion of common descent. However, there is nothing that logically ties these together, especially if you allow for design.
In Darwinism, each feature is a selected accident. Therefore, Darwinian phylogenetic trees often use parsimony as a guide, meaning that it tries to construct a tree so that complex features don’t have to evolve more than once.
The ID version of common descent, however, doesn’t have to play by these rules. The ID version of common descent includes a concept known as frontloading – where the designer designed the original organism so that it would have sufficient information for its later evolution. If one allows for design, there is no reason to assume that the original organism must have been simple. It may in fact have been more complex than any existing organism. There are maximalist versions of this hypothesis, where the original organism had a superhuge genome, and minimalist versions of this hypothesis (such as from Mike Gene) where only the basic outlines of common patterns of pathways were present. Some have objected to the idea of a superhuge genome, on the basis that it isn’t biologically tenable. However, the amoeba has 100x the number of base pairs that a human has, so the carrying capacity of genetic information for a single-cell organism is quite large. I’m going to focus on views that tend towards the maximalist.
Therefore, because of this initial deposit, it makes sense that phylogenetic change would be sudden instead of gradual. If the genetic information already existed, or at least largely existed in the original organism, then time wouldn’t be the barrier for it to come about. It also means that multiple lineages could lead to the same result. There is no reason to think that there was one lineage that lead to tetrapods, for instance. If there were multiple lineages which all were carrying basically the same information, there is no reason why there weren’t multiple tetrapod lineages. It also explains why we find chimeras much more often than we find organs in transition. If the information was already in the genome, then the organ could come into existence all-at-once. It didn’t need to evolve, except to switch on.
Take the flagellum, for instance. Many people criticize Behe for thinking that the flagellum just popped into existence sometime in history, based on irreducible complexity. That is not the argument Behe is making. Behe’s point is that the flagellum, whenever it arose, didn’t arise through a Darwinian mechanism. Instead, it arose through a non-Darwinian mechanism. Perhaps all the components were there, waiting to be turned on. Perhaps there is a meta-language guided the piecing together of complex parts in the cell. There are numerous non-Darwinian evolutionary mechanisms which are possible, several of which have been experimentally demonstrated. [[NOTE – (I would define a mechanism as being non-Darwinian when the mechanism of mutation biases the mutational probability towards mutations which are potentially useful to the organism)]]
Behe’s actual view, as I understand it, actually pushes the origin of information back further. Behe believes that the information came from the original arrangement of matter in the Big Bang. Interestingly, that seems to comport well with the original conception of the Big Bang by LeMaitre, who described the universe’s original configuration as a “cosmic egg”. We think of eggs in terms of ontogeny – a child grows in a systematic fashion (guided by information) to become an adult. The IDists who hold to Common Descent often view the universe that way – it grew, through the original input of information, into an adult form. John A. Davison wrote a few papers on this possibility.
Thus the common ID claim of “sudden appearance” and “fully-formed features” are entirely consistent both with common descent (even fully materialistic) and non-common-descent versions of the theory, because the evolution is guided by information.
There are also interesting mixes of these theories, such as Scherer’s Basic Type Biology. Here, a limited form of common descent is taken, along with the idea that information is available to guide the further diversification of the basic type along specific lines (somewhat akin to Vavilov’s Law). Interestingly, there can also be a common descent interpretation of Basic Type Biology as well, but I’ll leave that alone for now.
Now, you might be saying that the ID form of common descent only involves the origin of life, and therefore has nothing to do with evolution. As I have argued before, abiogenesis actually has a lot to do with the implicit assumptions guiding evolutionary thought. And, as hopefully has been evident from this post, the mode of evolution from an information-rich starting point (ID) is quite different from that of an information-poor starting point (neo-Darwinism). And, if you take common descent to be true, I would argue that ID makes much better sense of what we see (the transitions seem to happen with some information about where they should go next).
Now, you might wonder why I disagree with the notion of common descent. There are several, but I’ll leave you with one I have been contemplating recently. I think that agency is a distinct form of causation from chance and law. That is, things can be done with intention and creativity which could not be done in complete absence of those two. In addition, I think that there are different forms of agency in operation throughout the spectrum of life (I am undecided about whether the lower forms of life such as plants and bacteria have anything which could be considered agency, but I think that, say, most land animals do). In any case, humans seem to engage in a kind of agency that is distinct from other creatures. Therefore, we are left with the question of the origin of such agency. While common descent in combination with ID can sufficiently answer the origin of information, I don’t think it can sufficiently answer the origin of the different kinds of agency.