Recently at the University of Toronto I had the opportunity to debate atheist cosmologist Lawrence Krauss and theistic evolutionist Denis Lamoureux. The subject was “What’s Behind It All? God, Science, and the Universe.” Later, I was flattered to learn that famed biologist Richard Dawkins felt it necessary to come to the aid of his friend Dr. Krauss in Krauss’s dispute with me about whether the evolutionary process depends upon an ineliminable element of randomness.
How odd, however, that Professor Dawkins would weigh in for the purpose of defending an obviously incomplete and therefore, indefensible caricature of the standard neo-Darwinian evolutionary mechanism. In review of my talk in Toronto, Dawkins wrote at evolutionary biologist Jerry Coyne’s blog:
Meyer was terrible. . .When will these people understand that calculating how many gazillions of ways you can permute things at random is irrelevant. It’s irrelevant, as Lawrence said, because natural selection is a NONRANDOM process.1
Yes, of course, natural selection is a “nonrandom” process as Dawkins correctly insists. Rates of reproductive success correlate to the traits that organisms possess. Those with fitness advantages will, all other things being equal, out-reproduce those lacking those advantages.Got it. Understood.
Yet, clearly, there is more to the evolutionary mechanism than just natural selection. Instead, the standard neo-Darwinian evolutionary mechanism comprises (1) natural selection and/or (2) genetic drift acting on (3) adaptively random genetic variations and mutations (of various kinds). Moreover, as conceived from Darwin to the present, natural selection “selects” or acts to preserve those random variations that confer a fitness (or functional) advantage upon the organisms that possess them. It, further, “selects” only after such functionally advantageous variations (or mutations) have arisen. How could it do otherwise? Selection does not cause novel variations; rather, it sifts what is delivered to it by the random changes (e.g., mutations) that do cause variations. Such has been neo-Darwinian orthodoxy for many decades.
All this means that as a mechanism for the production of novel genetic information, natural selection does nothing to help generate functional DNA base (or amino acid) sequences. Rather it can only preserve such sequences (if they confer a functional advantage) once they have originated. In other words, adaptive advantage only accrues after the generation of new functional genes and proteins — after the fact, that is, of some (presumably) successful random mutational search. It follows that even if natural selection (considered separately from mutation) constitutes a non-random process, the evolutionary mechanism as a whole depends precisely upon an ineliminable element of randomness, namely, various postulated or observed mutational processes. (Nor is any of the above particularly controversial within evolutionary biology. No less friendly partisans to Krauss and Dawkins as Professors Larry Moran and P.Z. Myers both criticized Krauss for mischaracterizing the neo-Darwinian mechanism as wholly non-random, with Moran specifically blaming Krauss’s uncritical reliance upon Dawkins as the source of his misinformation.2)
In any case, the need for random mutations to generate novel base or amino-acid sequences before natural selection can play a role means that precise quantitative measures of the rarity of genes and proteins within the sequence space of possibilities are highly relevant to assessing the alleged power of mutation-selection mechanism. Indeed, such empirically derived measures of rarity are highly relevant to assessing the alleged plausibility of the mutation-selection mechanism as a means of producing the genetic information necessary to generating a novel protein fold. Moreover, given the empirically based estimates of the rarity (conservatively estimated by Axe3 at 1 in 1077 and within a similar range by others4) the analysis that I presented in Toronto does pose a formidable challenge to those who claim the mutation-natural selection mechanism provides an adequate means for the generation of novel genetic information — at least, again, in amounts sufficient to generate novel protein folds.5
Why a formidable challenge? Because random mutations alone must produce (or “search for”) exceedingly rare functional sequences among a vast combinatorial sea of possible sequences before natural selection can play any significant role. Moreover, as I discussed in Toronto, and show in more detail in Darwin’s Doubt,6 every replication event in the entire multi-billion year history of life on Earth would not generate or “search” but a miniscule fraction (one ten trillion, trillion trillionth, to be exact) of the total number of possible nucleotide base or amino-acid sequences corresponding to a single functional gene or protein fold. The number of trials available to the evolutionary process (corresponding to the total number of organisms — 1040 — that have ever existed on earth), thus, turns out to be incredibly small in relation to the number of possible sequences that need to be searched. The threshold of selectable function exceeds what is reasonable to expect a random search to be able to accomplish given the number of trials available to the search even assuming evolutionary deep time.
As with a hypothetical thief who is confronted with many more combinations than he has time to explore (in my offending bike lock analogy), the mutation and selection mechanism is much more likely to fail than to succeed in generating even a single new gene or protein in the known history of life on Earth. It follows that the neo-Darwinian mechanism — with its reliance on a random mutational search to generate novel gene sequences — is not an adequate mechanism to produce the information necessary for even a single new protein fold, let alone a novel animal form, in available evolutionary deep time.
Or to put the point differently, the hypothesis that a random search (aided after the fact by natural selection) did produce the genetic information necessary to morphological innovation in the history of life is overwhelmingly more likely to be false than true. That is one reason why so many mainstream evolutionary biologists are now abandoning neo-Darwinism and looking for other evolutionary mechanisms to account for fundamental innovations in the history of life.7
Readers who want to know more about the mathematical challenges posed to the neo-Darwinian mechanism may enjoy watching the Information Enigma video posted below, in which I and Doug Axe discuss these issues in greater detail:
(1) The full quotation from Dawkins is as follows:
Meyer was terrible, not because of his migraine but because of the content of his speech, which was written down BEFORE his migraine. When will these people understand that calculating how many gazillions of ways you can permute things at random is irrelevant. It’s irrelevant, as Lawrence said, because natural selection is a NONRANDOM process. You’d think they’d realise that if it were THAT easy to disprove evolution no scientist would take evolution seriously. Do they really think we are so very stupid? Or are they cynically playing to the gallery, dazzling the naive audience with big numbers like 10^77, while knowing full well they are irrelevant?
(2) As Moran noted at his Sandwalk blog:
During the debate, Stephen Meyer emphasized [the] random nature of evolution and its inability — according to him — to come up with new protein folds and new information in a reasonable amount of time. Krauss misunderstood the argument, which was based on the frequency of mutations, and tried to dismiss it by pointing out that evolution is not random — it’s directed and guided by natural selection.
Meyer corrected him by pointing out that the issue was the probability of mutations and not the probability of fixation once the mutation occurred. (This was when he was struggling with a migraine so he didn’t do as good a job as he could have.) Krauss stumbled on for a bit emphasizing natural selection and the fact that evolution is not random.
That was embarrassing. I think Krauss gets most of his information about evolution from Richard Dawkins so he (Krauss) probably doesn’t know about random genetic drift or historical contingency or any of the other features of the history of life that make it “random” (in the colloquial sense).
(3) Axe, Douglas. “Estimating the Prevalence of Protein Sequences Adopting Functional Enzyme Folds.” Journal of Molecular Biology 341 (2004): 1295-1315.
(4) Reidhaar-Olson, John, and Robert Sauer. “Functionally Acceptable Solutions in Two Alpha-Helical Regions of Lambda Repressor.” Proteins: Structure, Function, and Genetics 7 (1990): 306-16; Yockey, Hubert P. “A Calculation of the Probability of Spontaneous Biogenesis by Information Theory,” Journal of Theoretical Biology 67 (1977c): 377-98; Yockey, Hubert. “On the Information Content of Cytochrome C,” Journal of Theoretical Biology 67 (1977b) 345-376.
(5) For an explanation of why protein folds represent a fundamental unit of morphological innovation, see: Stephen C. Meyer, Darwin’s Doubt (San Francisco: HarperOne, 2014), pp. 189-192. Stabilizing a novel protein fold requires a long polypeptide chain with highly specific amino-acid sequence. Because of the corresponding combinatorial complexity associated with chains of length sufficient to stabilize a protein fold, it is extremely unlikely that a random mutational search will ever generate a novel protein fold, though mutation and natural selection does sometimes optimize pre-existing folds. Axe’s results estimating the rarity of functional amino-acid sequences (capable of generating a novel protein fold) provide empirical support for this conclusion. See Axe, D., & Gauger, A. (2015). “Model and Laboratory Demonstrations That Evolutionary Optimization Works Well Only If Preceded by Invention — Selection Itself Is Not Inventive,” BIO-Complexity (2015).
(6) Darwin’s Doubt, pp. 201-208.
(7) Almost without exception, biologists currently trying to reform evolutionary theory seek probabilistically favored pathways through the vast sterile sea of randomly arising variation. That is because a random (undirected) search is far too weak and slow a process, within the time available, to locate the functional islands on which natural selection can act. In the pithy phrase made popular early in the 20th century by the botanist Hugo de Vries, often quoted today by University of Zurich theorist Andreas Wagner, “Natural selection may explain the survival of the fittest, but it cannot explain the arrival of the fittest.” Wagner’s own recent work starts with what he calls the “hyperastronomical” numbers entailed by the problem of locating (by random search) a novel functional protein sequence within the space of all possible sequences. “If a trillion different organisms had tried an amino acid string every second since life began,” he writes, “they might have tried a tiny fraction of the 10^130 potential ones. They would never have found the one opsin string. There are a lot of different ways to arrange molecules. And not nearly enough time.” (See A. Wagner, The Arrival of the Fittest: Solving Evolution’s Greatest Puzzle [New York: Penguin, 2014], p. 4.) Just this week (22 March 2016), a lead editorial in the journal New Scientist worried that “any process built purely on random changes has a lot of potential changes to try. So how does natural selection come up with such good solutions to the problem of survival so quickly, given population sizes and the number of generations available?” New Scientist then promoted the ideas of University of Southampton evolutionary theorist Richard Watson, who argues that evolution “learns” in a fashion akin to “intelligent problem solving” (see R. Watson and E. Szathmáry, “How Can Evolution Learn?” Trends in Ecology & Evolution 31 :147-157). This change in explanatory perspective is needed, Watson and Szathmáry argue, because within “current evolutionary theory, it seems impossible that natural selection can anticipate what is needed in novel selective environments” — insofar as random search, by definition, anticipates nothing. “We think this offers the potential,” Watson and Szathmáry conclude, “to better explain how the process of random variation and selection results in the apparently intelligent designs it produces.” My emphasis, obviously — but it is a telling phrase. For additional examples of deep dissatisfaction with neo-Darwinian theory within evolutionary biology, see Shapiro, James A. “A 21st Century View of Evolution: Genome System Architecture, Repetitive DNA, and Natural Genetic Engineering.” Gene 345 (2005): 91-100; Kauffman, Stuart A. The Origins of Order: Self-Organization and Selection in Evolution (Oxford: Oxford University Press, 1993); Lynch, Michael. “The Frailty of Adaptive Hypotheses for the Origins of Organismal Complexity.” Proceedings of the National Academy of Sciences USA 104 (2007): 8597-604; Müller, Gerd B., and Stuart A. Newman. “Origination of Organismal Form: The Forgotten Cause in Evolutionary Theory.” Origination of Organismal Form: Beyond the Gene in Developmental and Evolutionary Biology, edited by G. B. Müller and S. A. Newman, 3-10 (Cambridge, MA: MIT Press, 2003).
Image credit: Anders Hesselbom (Own work) [Public domain], via Wikimedia Commons; Illustra Media.