Evolution on Purpose: The Inevitability of Intelligent Life?
Paleontologist Simon Conway Morris thinks the evolution of intelligent, conscious beings is no accident. In fact, it’s inevitable.
INTRO BY KATHRYN: Simon Conway Morris is a leading paleontologist at Cambridge University, best known for his work on convergent evolution, a process by which distantly-related organisms arrive at similar solutions for a basic activity (e.g., wings for flying, camera eyes for seeing). The pervasiveness of convergence in biology has implications for how we view the course of natural history and even our own existence: are we just a happy accident or is complex, intelligent life biologically inevitable? Conway Morris argues that convergent evolution points to the latter. In today’s post, guest author Pablo de Felipe puts the ideas of Simon Conway Morris into context and describes their relevance to the science/faith conversation. After reading this essay, check out the many excellent video clips featuring Simon Conway Morris at Test of Faith.
After spending three years learning the basic principles of chemistry at university, and with a clear bent in the program toward physics, I then turned to a specialization in biochemistry and molecular biology. There, I found myself in a completely different environment. One of the things that surprised me was how “classical” the portrayal of this worldview was. Everything was explained in a clock-like, mechanistic way that I thought I had left behind. It was as if biology was still sunk in a mechanistic Victorian dream. It came as no surprise then, that the sense that a conflict exists between science and faith was more intense in biology than among other branches of science. However, at the same time, and unlike the “mechanical universe” view, most of biology was descriptive, with little mathematics, few laws, and rare scientific predictions to guide research. Over the years, as I worked up to a PhD and then postdoctoral training, I came to accept that this was how it was, at least for the biological sciences. Many times I wondered whether biology could one day undergo something similar to the “relativity” or “quantum” revolutions of twentieth century physics. How might such a revolutionary biology appear?
Interestingly, my observation was not really original. Only about four years ago, I became aware of an interesting comment made by one of the giants of these revolutions that shocked physics and cosmology during the first third of the twentieth century. It was Georges Lemaître—both a scientist and a Catholic priest—who put forward the hypothesis of the Big Bang in 1931 and shortly afterwards (in 1933) gave an interview to the New York Times. The following reflections were recorded:
There is, the abbé admits, a varying sense of conflicts between the different branches of science. “The biologists seem to have peculiar difficulties,” He reasons. “There is every reason for this. They have only recently discovered a few guiding laws and principles. Hence, in the past their studies have been confusing rather than enlightening. In a way their subject-matter has been gross.
But give the biologists more laws like those of the Abbé Mendel and a new spirit is bound to awaken. The sense that this is a morally ordered universe will be inculcated. As soon as any science passes the mere stage of description it becomes a true science. Also it becames [sic] more religious. The mathematicians, the astronomers and the physicists, for example, have been very religious men, with a few exceptions. The deeper they penetrated into the mystery of the universe the deeper was their conviction that the power behind the stars and behind the electrons of atoms is one of law and goodness.1
The reason why those words so resonated with me was that by then I had already discovered the work of paleontologist Simon Conway Morris, when attending one of his lectures at the CiS/ASA meeting in Edinburgh in 2007. He was also concerned precisely by the lack of predictability in biology, particularly in evolutionary biology—the assumptions that contingency reigns supreme and the outcome of the ages is left to random events. He himself had a similar view during his early career in the late 1970s and 1980s, digging out from the famous Cambrian fossils of Burgess Shale in Canada a bizarre series of fantastic-looking early animals. Most of them were interpreted as precursors of branches in the tree of life that were dead-ends or were cut short in the early history of animals. Had an accident eliminated one of these early ancestors of the branch that led to us, indeed we would not be here! Famously, it was none other than the paleontologist Stephen Jay Gould who, in his well-known Wonderful Life (1989), arrived at the conclusion that history was dominated by contingency. He proposed that if we were “to rewind the tape of life” and replay it, intelligent, self-conscious beings would not be found in this imaginary alternative world.
However, by that time, the tide had already started to turn, and more work on Cambrian fossils from other deposits (e.g., China, Greenland) challenged the view that many of these early animals belonged to groups (phyla) unrelated to anything that evolved later. In some cases, it was found that they were related to animals still around us. But that was not all; Conway Morris started to focus his attention on one evolutionary phenomenon that, although accepted in conventional evolutionary theory, he thought had not been given the attention that it deserved: convergence. The history of life shows how, again and again, evolution converges on similar “solutions” to common biological “problems”: how to fly, how to swim, how to see, and so forth. In some cases, like the membrane-based wing of bats and feather-based wing of birds, the similarities have a deeper underlying ‘homology,’ given that mammals and birds are both tetrapods with limbs that were already present in their common ancestor (that is often called parallel evolution). However, this fact should not obscure the interesting conclusion that evolution does not favor absolutely free solutions, but certainly some are more probable than others. The idea is that physico-chemical natural laws impose certain constraints to what is possible, a sort of fine-tuning for biology. And, at this point, “predictability” in the evolutionary process and outcome enters the scene. A case of convergence where the players are more separate in the tree of life are ichthyosaurs (reptiles) and whales (mammals), which both share the fusiform shape of fishes (of course, they are all vertebrates; so in this sense all share a body plan, although the nature of the convergences in this case depends on very substantial and different modifications). And truly remarkable is one of the favorite stories of Conway Morris, involving vertebrates like us and very different invertebrates–like cephalopods (as octopus and squid) and certain cnidarians (like the cubozoan jelly fishes)–that have evolved similar (but not identical; the evolutionary pathway also matters!) camera-eyes. In this case, it is obvious that the common ancestor had nothing similar to camera-eyes at all.
Armed with these new ideas, Conway Morris took on Gould’s views in his book The Crucible of Creation (1998), which was later expanded in Life’s Solution: Inevitable Humans in a Lonely Universe (2003). He also combined the scientific discussion with a more philosophical discussion on what implications these ideas had. For him, the fact that certain “solutions” are found again and again points to the existence of ecological niches, with certain features constrained by the environmental circumstances, that sooner or later are occupied by one lineage or another. As Gould did before, Conway Morris also speculated about the implications for the existence of a self-conscious intelligent life form. For him, this is also a niche that has always been waiting to be occupied. In this regard, once life started we are not an accident of evolution, but an inevitability of evolution. As Gould pointed out, this is a reversal of the common understanding that the origin of life is inevitable in this universe (and probably widespread), but intelligent, human-like beings are purely accidental and probably uncommon: “The origin of life seems reasonably predictable on planets of earth-like composition, while any particular pathway, including consciousness at our level, seems highly contingent and chancy.”2 As with the medieval debate as to the existence of Antipodeans on the other side of the Earth, these debates are difficult to settle until someone actually goes there and sees “what’s up.” Sadly, it may be very difficult for us to navigate to these remote earthlike planets. Even so, as far as we know, we still have no evidence of other life forms apart from those on Earth—so it might well be that the origin of life is, after all, the real bottleneck in the evolutionary history, even if, as Conway Morris points out, this was a “completely natural” origin.3
Once life starts moving on, according to Conway Morris, the forces of natural laws would push and constrain it to paths across a biological landscape that could reach, not unexpectedly, the development of an intelligent being that would occupy a mental niche (of course, that does not mean that these beings had to be necessarily Homo sapiens!). As Conway Morris’ ideas have developed in recent years, he prefers the view of evolution as a search engine that explores the opportunities of life and, rather than just emerging in a pre-existent mental world, discovers it after navigating a constrained “hyperspace” of biological possibilities. We could be the first to set foot on this new beach, but it does not mean that we are entirely unique. As he remarks, the intelligence of other runners in this race of discovery, like corvids, dolphins and great apes, “suggests that equivalent search engines are only a few million years behind ourselves.”4 It could also be mentioned that, in our own family tree, other branches have also already arrived even closer to us (Neanderthals, Denisovans, Flores “hobbits,” and maybe even other forgotten hominids). Of course this is to fully embrace a sort of Platonic idealism—one that he does not hide.
Being a well-known scientist, Conway Morris’ views have not been unnoticed and, as it could be expected, have attracted much criticism. As with Lemaître, the accusations have quickly taken a personal turn, pointing to Conway Morris’ Christian commitment. In return, he has not shied away from pointing to the equally strong materialistic and atheistic commitments of some of his opponents (as was the case for Gould who at the least was sympathetic to Marxism). In particular, his ideas on the evolution of human intelligence have been criticised on the grounds that human intelligence is convergent to nothing else on Earth, and our intelligence is just a one-off, contingent, odd result. Since Conway Morris has, in fact, enlisted different animal intelligences as converging with the human intelligence, this has been dismissed as irrelevant and evidence of a Christian bias. However, this shows to me an interesting example of a pincer maneuver. For many years, when Christians reflected on the uniqueness of human beings and tried to link some human feature to the biblical concept of “image of God,” they were bombarded with examples of the intelligence of the animal kingdom to counter their supposed narcissism. Now that a Christian suggests that animal intelligence is a pointer towards intelligence not being a cosmic accident but a likely outcome of evolution, strangely the smart animals seem to cease to be of any philosophical relevance.
Christians and non-Christians alike should not be so nervous. Christianity can coexist with different, even opposite, scientific views. There is no need to appeal to science for a quick course in apologetics. That was the take-home message of the medieval antipodeans debate: in the end this was not a theological question, but a geographical question to be solved by travel, and we are happy to share our “blue marble” with our Australian fellow inhabitants—so we may draw lessons for the debates on extra-terrestrial life that have so many points in common with the debate on the antipodeans. Even if we can find a Christian scientist (such as Conway Morris) defending the view that convergence is consistent with Christianity (which by no means equates with concordism), would the opposite scientific interpretation of evolution mean the demise of Christianity? I doubt it. As in the case of cosmology, while many think today that Christianity is irreversibly wedded to the Big Bang model—and that was indeed the fear of Einstein and others that opposed Lemaître—their memory is perhaps at fault. With either a static universe or one with a continuous creation of matter, each hypothesis was also advocated by Christians in different historical periods as being congenial with a Christian God, while at the same time other Christians continued to worry that a God involved only at the beginning of the history of the cosmos would have to be equated with a deistic demiurge. From this perspective, throwing the Steady State universe as ammunition against Christianity was a futile exercise. That was also the reason that even in the nineteenth century some theologians (e.g., Kingsley, Moore) welcomed Darwin as a liberator from the clock-universe of Archdeacon Paley. The take-home message is that Christianity does not necessarily need to be hooked to any particular scientific theory, and it is better this way. That is what Simon Conway Morris affirms, in his well-known Boyle Lecture,5 talking about the consistency between Christianity and the Big Bang:
We should, however, be wary about such concord, this apparently happy marriage between cosmology and revealed religion. Not that concordance is out of the question, far from it. One should just be wary because scientific evidence is always provisional. Apparently irrefutable data or hypotheses have a curious habit of turning out to be gloriously, wonderfully wrong. From our present stance it is difficult to see what data could more satisfactorily explain many cosmological observations than the Big Bang, but we should be cautious of two things. First, to assume that the Big Bang is the same as God’s Creation, and second to fool ourselves that Creation ex nihilo is actually in any useful way open to comprehension. What surely matters, however, is that what can be brought out of nothing might be either returned to nothing or otherwise utterly transformed.6
About the author
Pablo de Felipe
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