Behe is incoherent on what design and evolution are
NOTE: This was first published here on 8.12.08, and is simply being re-published as a separate post now.
Behe tends to define terms as he desires, and then to redefine them again, with no consistency, reason, or scientific justification for doing so. For instance, he apparently just makes up his own definition of “macroevolution”:
Roughly speaking, microevolution describes changes that can be made in one or a few small jumps, whereas macroevolution describes changes that appear to require large jumps. DBB 14.
That simply isn’t true. Roughly speaking, microevolution involves changes within species, macroevolution occurs when species evolve. There is no difference in size of “jumps” inherent in the definitions at all. Here Behe seems (if witting–which is by no means certain) to be trying to change the discussion by shifting terms from what they mean.
Parenthetically, I suggested above that Behe might be unaware of his redefinition of microevolution and macroevolution (which remains a good possibility), and yet in his preface he would seem to suggest that “Darwinism” explains only microevolution, as it is known to science. There he writes:
Darwin was ignorant of the reasons for variation within a species (one of the requirements of his theory), but biochemistry has identified the molecular basis for it. DBB x.
He does not write that Darwin only explains variation within species, I would emphasize. Yet the context involves his continuous claims about how complex life is and how this complexity is not explained by Darwin. Your average creationist might be comforted by the quote above–which is in the preface, I repeat–for it seems to suggest that evolution might be very limited indeed.
Nevertheless, Behe rather quickly allows that larger scale evolution might happen by Darwinian means. On page four of DBB he writes that “Darwin’s idea might explain horse hoofs, but can it explain life’s foundation?”
Much of the rest of Behe’s argumentation seems to suggest that only complex metabolic pathways are really a problem for evolution. Paley had argued that the eye is so well-made (with “relational” parts) that it must be designed, while Behe’s argument against the evolution of the eye moves directly to the “black box” of the biochemistry of the eye (DBB, 18 and on).
Biochemical pathways are what require “large jumps” in his view, so he focuses on these. Nevertheless, he returns to granting very little to evolution by stating that Darwinism “explains microevolution very nicely” (DBB, 22). To most evolutionists and creationists, that allows very little evolution, in fact. And even if we were to accept his “definition” of microevolution, what does it even mean? What is a “large jump”?
At one point he even states that, “The behavior of hemoglobin can be achieved by a rather simple modification of the behavior of myoglobin…” and he states that therefore the case for design (he considers doubt regarding evolution to be evidence of design) of hemoglobin is weak (DBB, 207). And since hemoglobin apparently evolved prior to our split from lampreys, that would suggest that an enormous amount of evolution could occur. Mostly his “unevolvable” systems in DBB date back to the Cambrian or earlier.
As I have previously stated, I have not yet read Edge of Evolution. Nevertheless, reviews of the book give evidence that, as implied in DBB‘s preface, he may not allow for much unassisted evolution. Here is a quote from Edge of Evolution:
“If two mutations have to occur before there is a net beneficial effect – if an intermediate state is harmful, or less fit than the starting state – then there is already a big evolutionary problem.” (Edge of Evolution) p.106
Of course various evidences are against that conclusion (many disadvantageous mutations persist in populations), including the fairly recent report of the evolution of citrate transport in E. coli in extremely small populations (compared to the world, that is) and in a fairly short time. That’s not the point I wish to make with today’s entry, however. Currently I wish to demonstrate what extremely variable and mostly useless “criteria” he uses in these discussions, at least prior to Edge of Evolution. How anyone is to make sense of his incoherent usage of terminology and concepts, I do not know.
His use of the word “design” is equally reprehensible in intellectual terms, but I will leave discussion of that for tomorrow’s entry. These discussions of terms are not especially interesting, in my view, but they are essential to start off the discussion of the remainder of the issues in Behe’s writings. For, it is difficult to make sense of Behe, and one might end up criticizing what he wrote in one area, when he does not make the same error in another area.
Because Behe really has little or no idea of what is possible in evolution (the complexity that does make particular evolution more difficult in isolation also increases the material with which evolutionary processes may proceed, a fact that he does not adequately consider), and even less idea of what meaningful criteria for design are, he shifts the meaning of terms with little regard for scientific precision and accuracy. Yet it seems likely that anyone who thinks “anything might have been designed” (DBB, 205) is essentially uninterested in what terms and concepts mean–especially the most central word in his “explanation”, the word “design.”
This is part of a series of posts that I am combining into one long post, which may be found at Darwin’s Black Box.