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Evolutionary biology and the question of teleology
Studies in History and Philosophy of Biological and Biomedical Sciences xxx (2015) 1e7
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Evolutionary biology and the question of teleology Michael Ruse Program in the History and Philosophy of Science, Florida State University, FL, 32306, USA
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Teleologydwhat Aristotle called “final cause”dis trying to understand things in terms of the future, as when we ask about the plates on the back of the dinosaur, stegosaurus, and suggest that they might sometime be used to control the internal temperature of the brute. Recently the philosopher Thomas Nagel has argued for a wholesale embrace of teleological thinking in the sciences, particularly the life sciences. I argue that Nagel’s thinking is shoddy and ill-informed, but that in some sense biologists do (with reason) seem drawn to teleological understanding, and so the correct response is not outright rejection of the very idea but a more informed and sympathetic approach to those aspects of nature that seem to call for final cause thinking. Ó 2015 Elsevier Ltd. All rights reserved.
Keywords: Thomas Nagel Teleology Final cause Charles Darwin Natural selection Arms race
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1. Thomas Nagel’s bad book Recently the well-known American philosopher Thomas Nagel published a book, Mind and Cosmos, in which he argued that the thus-far insoluble problems of the biological sciences (especially in the field of evolution) suggest that researchers need to return to teleological explanations. If contemporary research in molecular biology leaves open the possibility of legitimate doubts about a fully mechanistic account of the origin and evolution of life, dependent only on the laws of chemistry and physics, this can combine with the failure of psychophysical reductionism to suggest that principles of a different kind are also at work in the history of nature, principles of the growth of order that are in their logical form teleological rather than mechanistic. (Nagel, 2012, 7) To say that the book was not well received is a bit like saying that Hitler had a thing about Jews. Harvard psychologist Steven Pinker wrote on Twitter of “the shoddy reasoning of a once-great thinker.” Daniel Dennett bluntly said that Nagel’s work “isn’t worth anythingdit’s cute and it’s clever and it’s not worth a damn.” And the Guardian newspaper carried a headline that Nagel’s book was the
most despised science book of 2012 (Chorost, 2013). Perhaps expectedly, the Creationists loved it! Mind and Cosmos is not a great book (Ruse, 2010). Nagel’s knowledge of biology is breathtaking in its nigh-willful superficiality. One suspects that only someone who knew his conclusion before he started his research could argue in so shallow and misleading a fashion. Nagel is no Creationist. One accepts his claim to be an atheist. He does however have a record of praising Creationist booksdmore specifically, he praises books by the so-called Intelligent Design Theorists, what I call “Creationism Lite”dand one senses a shared contempt for and fear of arguments about evolutionary origins. (See Behe, 1996.) Perhaps if we were to identify one single factor for this hostilitydand this is made very clear by Nageldit is that evolutionary thinking belittles the worth of humankind. We are reduced to mere matter in motion and that which makes us somehow special is downgraded and denied. I will not here go into more details; what I would like to do here is turn the tables somewhat and pick up and take seriously Nagel’s claim that we need to take up teleological modes of understanding. Given that I am one who has written critically of Nagel’s book, it may seem odddhypocritical perhapsdthat I would do so. But I am motivated by the ferocity of the reactions to Mind and Cosmos. Bad books appear on a regular basis. Generally such books get little press and they make no waves and are soon forgotten. Why then did Nagel’s book so upset people?
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In part obviously the reaction was because of the Creationism factor. Any book praised by Creationists is going to be disliked and the fact that already Nagel had earlier spoken warmly of Creationist works did not help. I suspect however that there was something about teleology in itself that rattled people. This mode of thought is in some sense considered not just wrong but unclean, and when Nagel started pushing it, emotions were generated and poured forth. Embracing and advocating teleology is a bit like smoking in someone’s living room. People used to do it but they don’t anymore and very much disapprove of those that still do. It is just something that is alien to decent people, or perhaps as with smoking not done now but with a hint of past pleasures and urges that must now be repressed. Nothing like a reformed Magdalene for sanctimonious disapproval. This is the hunch I want to pursue and unpack. Teleology unnerves people because although it is wrong it is still tempting. 2. What is teleology? What does one mean by “teleology,” or more specifically what is a “teleological explanation”? It is a form of explanation that makes reference to causes that can be understood only in terms of the future (Ruse, 2003). To make sense of this definition, contrast teleological explanation with more usual forms of explanation that make reference to “proximate” or “efficient” causes. These latter explanations are in terms of causes that are understood in terms of past or present. So for instance if I say (to take a biological example) the reason why a child has Down’s syndrome is because he has an extra chromosome, I am explaining the physical and psychological nature of the child in terms of some cause that already exists. In a teleological explanation I am explaining in terms of causes that do not yet exist. If I say (to take another biological example) the plates on the back of stegosaurus exist in order to (for the purpose of, have the function of) regulating the heat of the animal, I am talking of what I expect to happen. The stegosaurus has its plates now. Later in the day, the sun heats the brute and then the plates start to radiate heat or to catch the cooling breezes in the air. Note therefore that there is not really a straight analogy between proximate causes and teleological causes. In the former case, you know that the cause exists or existed. In the latter case, the cause may never exist! It could be that the stegosaurus falls of a cliff and never uses its plates for their intended purpose. How then can there be reference to the future if the future never occurs? There are two proffered explanations. One is that teleological explanation occurs in the context of intelligent design. The purpose of the airbags in the automobile is to explode on major contact. It may be that the airbags never are used for this purpose, but the point is that someone at some point thought about what might happen and designed and built them accordingly. The future reference comes because someone thought about it. (This has its roots in the thinking of Plato.) The other explanation is that there is some kind of special force that is future directed. The force may not be a thinking force, but it seeks out phenomena or events in the future. The idea here is rather like the goal-directed system you get in rockets. As the target moves, the rocket adjusts its direction accordingly with the aim of hitting the target. The analogy is not quite exact, because in the case of rockets someonedsome bright engineer from MITddesigned the seeking system. But you get the idea. (This has its roots in the thinking of Aristotle.) 3. Charles Darwin and natural selection I will take seriously Nagel’s claim that he is not a believer, so I accept that he does not see the teleology of biology as literally designed. I presume therefore that he subscribes to some kind of view that has special forcesd“vital forces”dfocused on the future.
This is a view made popular at the end of the nineteenth century by a group known naturally as “vitalists,” led by the German embryologist Hans Driesch who spoke of “entelechies” and the French philosopher Henri Bergson who spoke of “élans vitaux.” (See Bergson, 1907 and Driesch, 1908.) I will not stop here to criticize this view because this was done so often in the last century, but I will agree with the critics that the main problem with vital forces is that they seem not to add to the explanatory mix. Once you have finished talking about DNA and that sort of thing, it really doesn’t seem that adding vital forces adds at all to one’s understanding. However, I will agree with Nagel that there does seem to be something teleological about organism talkdwe do have forward referencedand that this needs explaining. The eye does serve the future purpose of seeing. What I would say is that as always in science we have a metaphor at work here, the metaphor of design. We look at the eye as if designed, even though it may not be, and the reason why we do this is because it does seem as if designed and using the metaphor has incredible heuristic value. In the stegosaurus case, thinking of the plates as if designed for cooling led to all sorts of interesting hypotheses about blood flow, that were later confirmed. Where I part company with Nagel is in thinking that, in the case the design of organisms, we have a more than adequate naturalisticdmechanisticdaccount. This is Charles Darwin’s theory of evolution through natural selection. In his Origin of Species, Darwin argued that population pressures lead to a struggle for existence and (more importantly) reproduction. The successful in the struggle will tend to be different from the unsuccessful and it will be the differences that count. Given enough time there will thus be a natural form of selection. Let it be borne in mind how infinitely complex and close-fitting are the mutual relations of all organic beings to each other and to their physical conditions of life. Can it, then, be thought improbable, seeing that variations useful to man have undoubtedly occurred, that other variations useful in some way to each being in the great and complex battle of life, should sometimes occur in the course of thousands of generations? If such do occur, can we doubt (remembering that many more individuals are born than can possibly survive) that individuals having any advantage, however slight, over others, would have the best chance of surviving and of procreating their kind? On the other hand, we may feel sure that any variation in the least degree injurious would be rigidly destroyed. This preservation of favourable variations and the rejection of injurious variations, I call Natural Selection. (Darwin, 1859, 80e81) Note that Darwin’s mechanism not only leads to change but to change of a particular kind. Organisms will develop end-directed features like hands and eyes, what biologists call “adaptations.” There will be an appearance of design, without need of vital forces or direct interventions by a designer. Blind mechanical law can do everything. It is not so much that final-cause type understanding is now gonedDarwin himself happily talked about final causes and he certainly thought that this involved explaining in terms of the futuredbut that teleology is now subsumed under mechanism (Ruse, 2009). 4. The challenge of history For the Greeks, this would have been the end of the story. They, at least the philosophers, had no real thoughts of development through time. Their world was eternal and essentially unchanging. Historical development comes later and is due in no small part to the biblical narrative, with the movement from Eden to Calvary and later. It was after the Scientific Revolution, during the
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Enlightenment starting at the beginning of the eighteenth century, that people started really to think seriously about development over time. With this came another dimension to the story of teleology. Now the end points, future references, were not to individualsdthe parts of organisms for instancedbut to the end or culmination of time. The question now was about the direction of history and how we can and should interpret the present in terms of what is to come rather than simply in terms of what has passed. Essentially this is the story of progress (Ruse, 1996). It is true of course that one might see history as culminating in humans driving themselves off the edge of a cliff, and in this age of nuclear weaponry and global warming who can gainsay such thinking? But traditionally those thinking about historical development have tended to be optimists, to have endorsed thoughts of progress. In the world of culture, of society, this is the idea that socially and intellectually we humans are improving and will continue to do so. There is an upward pattern to history and we should see stages not only as reflecting what has happened in the past but what was bound to happen in the future. There is change and there is direction and to understand it we need to see where it is headed. In other words we need teleological understanding. And, increasingly through the eighteenth century, people argued that the same is true in the world of organisms. They too show progress, from the simple to the complex, from that lacking in worth to that with fullest worth, from, as it was called, the monad to the man. Some thought that the progress was more conceptual than actual, in the sense of talking of linked development from one to the next that is to say of physical evolution. Others, with greater or lesser enthusiasm accepted the reality of the connections. Either way, as with adaptations, here also teleological understanding is demanded, as we see the futuredin the sense that humans once did not exist and then later they diddas important to understanding as is the past. Cultural progress and biological progress were never two separate ideas. The latter was always an epiphenomenon of the former and often used in a somewhat circular fashion to support the former. Denis Diderot, the French encyclopedist, was a pioneer. “Just as in the animal and vegetable kingdoms, an individual begins, so to speak, grows, subsists, decays and passes away, could it not be the same with the whole species?” (Diderot, 1943, 48, quoting On the Interpretation of Nature, 1754) He made no bones about seeing a link between his social views and his scientific speculations. “The Tahitian is at a primary stage in the development of the world, the European is at its old age. The interval separating us is greater than that between the new-born child and the decrepit old man” (Diderot, 1943, 152, quoting Supplement to Bougainville’s Voyage, 1772). Later in the century Charles Darwin’s grandfather, the physician Erasmus Darwin, fell into the same pattern. Imperious man, who rules the bestial crowd, Of language, reason, and reflection proud, With brow erect who scorns this earthy sod, And styles himself the image of his God; Arose from rudiments of form and sense, An embryon point, or microscopic ens! (Darwin, 1803, 1, 11, 295e314)
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Surely this all came to an end with Charles Darwin? Evolution was now far more than something merely riding on the back of the idea of cultural progress. Interestingly, however, its connection with cultural progress was not severed. Evolutionists continued to be thoroughly soaked in thoughts about cultural progress and they continued to see this reflected in the history of organic life. This was true of Darwin: “The inhabitants of each successive period in the world’s history have beaten their predecessors in the race for life, and are, in so far, higher in the scale of nature; and this may account for that vague yet ill-defined sentiment, felt by many palæontologists, that organization on the whole has progressed.” (Darwin, 1859, 345) And this kind of thinking continued right down into the twentieth century. There have been those, like the late Stephen Jay Gould, who attacked the whole notion of biological progress. He wrote of biological progress as “a noxious, culturally embedded, untestable, nonoperational, intractable idea that must be replaced if we wish to understand the patterns of history” (Gould, 1988, 319). He argued that there is nothing inevitable about the emergence of humans. Making joking reference to the asteroid that hit the Earth 65 million years ago and wiped out the dinosaurs, making possible the age of mammals, he wrote: “Since dinosaurs were not moving toward markedly larger brains, and since such a prospect may lie outside the capabilities of reptilian design., we must assume that consciousness would not have evolved on our planet if a cosmic catastrophe had not claimed the dinosaurs as victims. In an entirely literal sense, we owe our existence, as large and reasoning mammals, to our lucky stars” (Gould, 1989, 318). Actually, as we shall see, Gould’s full position on the subject was much more complex than a simple denial of progress. But Gould apart, the fact is that many, perhaps most, continued to believe in such progress. Today’s most distinguished living evolutionist, Edward O. Wilson of Harvard University, is open in his fervent belief in biological progress. “The overall average across the history of life has moved from the simple and few to the more complex and numerous. During the past billion years, animals as a whole evolved upward in body size, feeding and defensive techniques, brain and behavioral complexity, social organization, and precision of environmental controldin each case farther from the nonliving state than their simpler antecedents did” (Wilson, 1992, 187). Adding: “Progress, then, is a property of the evolution of life as a whole by almost any conceivable intuitive standard, including the acquisition of goals and intentions in the behavior of animals.” (See also Wilson, 1975.) Others agree. In his great popular overview of modern evolutionary thinking, The Blind Watchmaker (1986), Richard Dawkins refers to Harry Jerison’s (1973) notion of an Encephalization Quotient, this being a kind of universal animal IQ, that works from brain size and subtracts the gray matter simply needed to get the body functioningdwhales necessarily have bigger brains than shrews, because they have bigger bodies. What counts is what is left when you take off the bodyfunctioning portion. Thus measured, humans come way out on top, leading Dawkins (1986, 189) to reflect: “The fact that humans have an EQ of 7 and hippos an EQ of 0.3 may not literally mean that humans are 23 times as clever as hippos!” But, he concludes, it does tell us “something.” 5. Problems with progress
Explicitly, Erasmus Darwin tied in this vision of the organic world with his hopes and beliefs about the social world: the idea of organic progressive evolution “is analogous to the improving excellence observable in every part of the creation; . such as the progressive increase of the wisdom and happiness of its inhabitants” (Darwin, 1794e96, 509).
Why would anyone worry about biological progress? Couldn’t you say that although it has the odor of teleologydthe course of evolution is directed to the end point of humankinddthe system is just as mechanistic as adaptation, something else with the odor of teleology but entirely mechanistic? In fact, the same process is at work in both cases, natural selection in the short term for
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adaptation and natural selection in the long term for progress. As it happens, it is pretty clear that Gould’s objections to biological progress were more social than scientific. He believed in social progress but thought biological progress a barrier to its fulfillment. Too easily biological progress is used to justify racismdblacks, Asians, Jews down the scale and white Anglo-Saxons at the topdand he fought against his all of his life. But this kind of thinking aside, the fact is that many find beliefs in biological progress something of an embarrassment. At the specific level, because whatever Darwin himself may have thought, it seems that his theory quite undermines thoughts of biological progress. On the one hand, natural selection is relativistic. It is not a tautology but it does say that what is of adaptive advantage in one situation is not necessarily of adaptive advantage in other situations. A darkskinned mouse is camouflaged on clay soil whereas a lightskinned mouse is camouflaged on sandy soil. On the other hand, the variationsdthe raw building blocks of evolutiondare random in the sense of not occurring according to need. There is no direction in their nature. This fact too seems to tell against inevitable upwards climb. At the general level, seeing the history of life on Earth as moving up towards the best of all possible organisms, Homo sapiens, is to put value judgments right up front of one’s science. And this is considered incompatible with good science. Since the Scientific Revolution, nature has been seen simply as matter in motion, without point, without purpose. Hence professional science itself must be value free. It cannot promote things one wants. Only things as they are. In the words of Karl Popper (1972), science is “knowledge without a knower,” meaning that human interests are excluded. Thus although there may be belief in biological progress, the tendency is to downplay it or exclude it from explicit discussion. 6. Naturalizing progress Or to argue that it is no longer a value laden notion! As in the case of final causes with respect to individual features (adaptations), the hope is that the teleology of history can be put on a happy mechanical foundation. How can this be done? God cannot enter into the picture. Neither can vital forces. Natural selection itself, or some equally naturalistic alternative, must do the explaining. Part of the trick will be giving a definition or characterization of what is being produced, something that humans have more than any other organisms. One can hardly simply say “human-like features” because that just gets you into a circle. They must be features that we in some sense judge desirable, although the judgment itself cannot be part of the science. Generally the move is towards some kind of complexity. Darwin led the way here. In the third edition of the Origin (1861) he admitted that “naturalists have not defined to each other’s satisfaction what is meant by an advance in organisation.” However, he was prepared to make a suggestion of his own. Amongst the vertebrata the degree of intellect and an approach in structure to man clearly come into play. It might be thought that the amount of change which the various parts and organs undergo in their development from the embryo to maturity would suffice as a standard of comparison; but there are cases, as with certain parasitic crustaceans, in which several parts of the structure become less perfect, so that the mature animal cannot be called higher than its larva. Von Baer’s standard seems the most widely applicable and the best, namely, the amount of differentiation of the different parts (in the adult state, as I should be inclined to add) and their specialisation for different functions; or, as Milne Edwards would express it, the completeness of the division of physiological labour. (Darwin, 1861, 133)
7. Arms races How are you going to get this complexity by natural means? Again Darwin comes to our aid. Basically you argue that selection leads to competition and the more subtle or sophisticated or complex will win out in the end. Intelligence is at the top of complexity and so humans come out top. If we look at the differentiation and specialisation of the several organs of each being when adult (and this will include the advancement of the brain for intellectual purposes) as the best standard of highness of organisation, natural selection clearly leads towards highness; for all physiologists admit that the specialisation of organs, inasmuch as they perform in this state their functions better, is an advantage to each being; and hence the accumulation of variations tending towards specialisation is within the scope of natural selection. (Darwin, 1861, 134) In the twentieth century, this kind of thinking was refined and the discussion was cast in terms of “arms races.” Lines of organisms compete and improvement occursdthe prey gets faster and so does the predator. The person who really developed this notion was Julian Huxley. Likening biological evolution to the competition between nations in preparation for war, and making reference (writing in 1912) to the naval build-up between Germany and Britain, Huxley wrote: “The leaden plum-puddings were not unfairly matched against the wooden walls of Nelson’s day.” He then added that today “though our guns can hurl a third of a ton of sharp-nosed steel with dynamite entrails for a dozen miles, yet they are confronted with twelve-inch armor of backed and hardened steel, water-tight compartments, and targets moving thirty miles an hour. Each advance in attack has brought forth, as if by magic, a corresponding advance in defence.” Explicitly, Huxley likened this to the organic world, for “if one species happens to vary in the direction of greater independence, the inter-related equilibrium is upset, and cannot be restored until a number of competing species have either given way to the increased pressure and become extinct, or else have answered pressure with pressure, and kept the first species in its place by themselves too discovering means of adding to their independence” (Huxley, 1912, 115e16). And so finally: “it comes to pass that the continuous change which is passing that through the organic world appears as a succession of phases of equilibrium, each one on a higher average plane of independence than the one before, and each inevitably calling up and giving place to one still higher.” Richard Dawkins picks right up on this sort of thinking. In a paper co-authored with fellow biologist John Krebs he writes that even “if modern predators are no better at catching prey than Eocene predators were at catching Eocene prey, it does at first sight seem to be an expectation of the arms race idea that modern predators might massacre Eocene prey. And Eocene predators chasing modern prey might be in the same position as a Spitfire chasing a jet” (Dawkins & Krebs, 1979, 490). In other words, in Dawkins’s happy Darwinian world, it all comes out right in the end. As in the military world, weaponry has become increasingly electronic, and those organisms with the biggest on-board computers win out. 8. Niches A second Darwinian approach can be found in one of the many essays that Stephen Jay Gould penned for Natural History. This may seem strange, because we have seen how he argued against biological progress. However, as I have pointed out, it is clear that this opposition was more political than
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epistemological, and if you look at Gould’s overall corpus, you find that throughout he had yearnings for some kind of improving development with humans winning out in the end. Think about ecological nichesdlike the shelter provided by trees or the safety of burrows underground. One might say that, thanks to natural selection, organisms are constantly looking and prodding to find new niches and, when they do, they enter and exploit them. The first animals to get up to and survive on dry land found a whole new area in which they and their descendents could live and thrive. Culture can be described as one such niche, the niches that humans have found and entered. If not us, was it not predictable that someone on Earth would find and enter the niche? Why should this not happen repeatedly, if not here on Earth (because you might say that we have now blocked the entrance) then elsewhere in the universe? Note that selection here is doing the work, but it is not doing it by one organism beating out another and thus proving its superiority. The superiority if such there be comes from the niche itself and rather confers this on its inhabitants. So there are no longer the obvious opportunities for racism and sexism. In an essay on the search for extraterrestrial life, Gould wrote: “I can present a good argument from “evolutionary theory” against the repetition of anything like a human body elsewhere; I cannot extend it to the general proposition that intelligence in some form might pervade the universe” (Gould, 1985, 411). He then went on to quote the leading twentieth-century evolutionist Theodosius Dobzhansky, writing in a textbook with other major evolutionists: “Granting that the possibility of obtaining a man-like creature is vanishingly small even given an astronomical number of attempts. there is still some small possibility that another intelligent species has arisen, one that is capable of achieving a technological civilization” (412). About this passage, Gould commented: “I am not convinced that the possibility is so small.” He then gave an argument that evolutionary convergence (where two different lines evolve essentially similar adaptations to survive and reproduce) suggests that even though major intelligence has arisen but once on this earth, it is quite possible that elsewhere in the universe it has arisen quite independently. Conscious intelligence has evolved only once on earth, and presents no real prospect for reemergence should we choose to use our gift for destruction. But does intelligence lie within the class of phenomena too complex and historically conditioned for repetition? I do not think that its uniqueness on earth specifies such a conclusion. Perhaps, in another form on another world, intelligence would be as easy to evolve as flight on ours. (412) This argument has been picked up (apparently independently) and promoted by the paleontologist Simon Conway Morris, who (as a Christian) is very keen to argue for the inevitability of the appearance of humans. He argues that only certain areas of what we might call “morphological space” are welcoming to life forms (the center of the sun would not be, for instance) and that this constrains the course of evolution. Again and again, as Gould argued, organisms take the same route into a pre-existing niche. The saber-toothed, tiger-like organisms are a nice example, where the North American placental mammals (real cats) were matched right down the line by South American marsupials (thylacosmilids). There existed a niche for organisms that were predators, with cat-like abilities and shearing/stabbing-like weapons. Darwinian selection found more than one way to enter itdfrom the placental side and from the marsupial side. It was not a question of beating out others but of finding pathways that others had not found.
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Conway Morris argues that, given the ubiquity of convergence, we must allow that the historical course of nature is not random but strongly selection-constrained along certain pathways and to certain destinations. Most particularly, some kind of intelligent being was bound to emerge. After all, our own very existence shows that a kind of cultural adaptive niche existsda niche that prizes intelligence and social abilities. If brains can get big independently and provide a neural machine capable of handling a highly complex environment, then perhaps there are other parallels, other convergences that drive some groups towards complexity. Could the story of sensory perception be one clue that, given time, evolution will inevitably lead not only to the emergence of such properties as intelligence, but also to other complexities, such as, say, agriculture and culture, that we tend to regard as the prerogative of the human? We may be unique, but paradoxically those properties that define our uniqueness can still be inherent in the evolutionary process. In other words, if we humans had not evolved then something more-or-less identical would have emerged sooner or later. (Conway Morris, 2003, 196)
9. Complexity just happens A third suggestion finds hints in Darwin but it is not very Darwinian, inasmuch as it does not rely on natural selection. It basically says that there is a natural tendency to complexity and over time you will get what you want. In one of his early notebooks Darwin wrote: The enormous number of animals in the world depends of their varied structure & complexity. d hence as the forms became complicated, they opened fresh means of adding to their complexity. d but yet there is no necessary tendency in the simple animals to become complicated although all perhaps will have done so from the new relations caused by the advancing complexity of others. d It may be said, why should there not be at any time as many species tending to dis-development (some probably always have done so, as the simplest fish), my answer is because, if we begin with the simplest forms & suppose them to have changed, their very changes tend to give rise to others. (Barrett et al. 1987; Notebook, E, 95e6) Of course, for Darwin, selection was always hovering, so he would have seen this process connected to change towards adaptive advantage. A purer version, if we might so describe it, can be found in the thought of Herbert Spencer. To characterize the phenomenon of complexity, something he admitted he got from the Naturphilosoph Friedrich Schelling via the writings of the poet Samuel Coleridge, Spencer introduced two terms which have had a very long shelf life. Simple organisms (or states of affairs generally) are “homogeneous. Complex organisms (or states) are “heterogeneous.” The course of progress therefore is from the homogeneous to the heterogeneous. As he developed his thinking around the time that Darwin published the Origin, Spencer fell more and more under the spell of physics. This led to his full-blown theory of “dynamic equilibrium.” He argued that organisms, or a state, exist in a balancedworking normally, with everything in equilibria. Then somethingdquite possibly something from outsidedacts to upset the balance and things get into play. They are striving always to regain equilibrium, just as a ball bearing at the bottom of a bowl, if disturbed, will naturally tend back down to the center and to regained equilibrium. Eventually this balance will be achieved, but
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it will be a new balance, higher than before, and with a greater heterogeneity than before. Backing all of this, Spencer gave a kind of metaphysical principledone that may or may not have been behind the notebook passage of Darwin quoted abovedthat causes always proliferate in several effects but never conversely. So complexity emerges naturally. “Every active force produces more than one change e every cause produces more than one effect” (Spencer, 1857, 32). More recently, in his book Full House (1996), Gould argued that there is certainly no necessary, selection-driven process of progressive evolution leading to greater complexity. However, he did at the same time agree that the natural course of events would lead to ever-more complex organisms. These ideas have been picked up and developed at some length recently in a new book by two academics at Duke University, one a biologist (Daniel McShea) and the other a philosopher (Robert Brandon). In Biology’s First Law: The Tendency for Diversity and Complexity to Increase in Evolutionary Systems, they offer a very Spencerian vision of the evolutionary process (McShea & Brandon, 2010). They call their law the “zeroforce evolutionary law,” or ZFEL. It is formulated as follows: “In any evolutionary system in which there is variation and heredity, in the absence of natural selection, other forces, and constraints acting on diversity or complexity, diversity and complexity will increase on average.” What do McShea and Brandon mean by complexity? Certainly nothing to do with natural selection as such. They say that complexity is “a function only of the amount of differentiation among parts within an individual.” Elsewhere they say ““complexity” just means number of parts types or degree of differentiation among parts.” They are very careful to specify that this has nothing to do with adaptation. Indeed they say “in our usage, even function less, useless, part types contribute to complexity. Even maladaptive differentiation is pure complexity.” How could this complexity come about? It all seems to be a matter of randomness, meaning not that there are no causesdwith orthodox Darwinians they would agree that the building blocks of evolution (mutations) have physical causesdbut that there is no direction in the nature of the building blocks or in what happens to them once they appear. With Gould, and I think with Spencer, they simply believe that over time more and more things will happen and pieces will be produced and thus complexity will emerge. It is the inevitability of the drunkard falling into the gutter.
have their costs, namely the need of large quantities of high-grade fuel (the bodies of other animals) and there are times when this might not pay. In the immortal words of the late John J Sepkoski: “I see intelligence as just one of a variety of adaptations among tetrapods for survival. Running fast in a herd while being as dumb as shit, I think, is a very good adaptation for survival” (Ruse, 1996, 486). The niche suggestion is clever and may have some real worth. However, as critics of Darwinism like geneticist Richard Lewontin (1983) point out non-stop, niches do not exist in splendid isolation waiting to be found. They are as much made as discovered. The niche for insects at the tops of Brazilian junglesdapparently a very rich home for much lifedobviously would not exist were there no trees. The point is not whether humans have evolved, because obviously we have. The question is whether we would necessarily evolve given the evolutionary processdeither here or somewhere else in the universe. Who is to say that there are not many other possible niches that would produce something quite different from consciousness but as effective? Don’t ask me what they are, because the whole point is that I don’t know! I am just asking why they are ruled out. Finally the natural tendency to complexity. This may well be true and it may be important. Darwin is surely right about the way in which it leads to a diversity of organisms. But again I am not quite sure why humansdor human-like beingsdshould emerge. Perhaps they will. Perhaps they won’t. The point is that without some stronger reason, like those supplied by the Greeks, you might be waiting a long time for nothing. And the Greek solutions are not acceptable in modern science. 11. Envoi All of this may leave the reader somewhat dissatisfied. There has to be some reason why humans, the best of all organisms, emerged. And yet, given mechanism, there is no satisfactory answer or prospect of such an answer. Which brings us back to Thomas Nagel. I suggest that for all of the inadequacies of his own positiondit was reprehensible to argue in the shoddy fashion to be found in Mind and Cosmosdhe has put his finger on a sore point. Evolutionists want teleology but they cannot have it. And perhaps that goes some way towards explaining the vehemence of their reactions to his book.
10. Close but no cigar References So, pulling back, what do we say about historical direction and teleology? Interesting and stimulating though the various naturalistic proposals may be, nothing quite works as well and as definitively as one might like. In a way, the whole talk about complexity is problematic. And even if one solved the general issues, one might query whether any proposal would unambiguously classify humans as the top organisms. One of the most interesting things to emerge from the Human Genome Project was just how few genes are needed to produce so much. What about consciousness? Is that complex or simple? Note that this is not to say that humans are not special or that they should not be valued over all other organisms. I certainly value humans over warthogs. It is just a matter of finding characteristics of humans that do not end in circularity and that would be produced by evolutionary processes. Analogously, all of the mechanisms for producing human-like beings are suggestive but hardly definitive. Most Darwinians accept arms races although there are critics. The fossil record does not suggest that predator-prey encounters always improve speed. But even if you accept their importance, whether they will necessarily produce intelligence is another matter. So it is hard to claim that in some sense being humanlike is absolutely good. Even brains
Barrett, P. H., Gautrey, P. J., Herbert, S., Kohn, D., & Smith, S. (Eds.). (1987). Charles Darwin’s notebooks (pp. 1836e1844). Ithaca, N.Y.: Cornell University Press. Behe, M. (1996). Darwin’s Black Box: The biochemical challenge to evolution. New York: Free Press. Bergson, H. (1907). L’évolution créatrice. Paris: Alcan. Chorost, M. (2013). Where Thomas Nagel went wrong. The Chronicle of Higher Education, no. May 13. Conway Morris, S. (2003). Life’s solution: Inevitable humans in a lonely universe. Cambridge: Cambridge University Press. Darwin, E. (1794e1796). Zoonomia; or, the laws of organic life. London: J. Johnson. Darwin, E. (1803). The temple of nature. London: J. Johnson. Darwin, C. (1859). On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: John Murray. Darwin, C. (1861). Origin of species (3rd ed.). London: John Murray. Dawkins, R. (1986). The Blind Watchmaker. New York, N.Y.: Norton. Dawkins, R., & Krebs, J. R. (1979). Arms races between and within species. In , 205. Proceedings of the Royal Society of London, B (pp. 489e511). Diderot, D. (1943). Diderot: Interpreter of nature. New York: International Publishers. Driesch, H. (1908). The science and philosophy of the organism. London: Black. Gould, S. J. (1985). The Flamingo’s Smile: Reflections in natural history. New York: Norton. Gould, S. J. (1988). On replacing the idea of progress with an operational notion of directionality. In M. H. Nitecki (Ed.), Evolutionary progress (pp. 319e338). Chicago: The University of Chicago Press. Gould, S. J. (1989). Wonderful life: The Burgess Shale and the nature of history. New York, N.Y.: W. W. Norton Co.
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M. Ruse / Studies in History and Philosophy of Biological and Biomedical Sciences xxx (2015) 1e7 Gould, S. J. (1996). Full house: The spread of excellence from Plato to Darwin. New York, N.Y.: Paragon. Huxley, J. S. (1912). The individual in the animal kingdom. Cambridge: Cambridge University Press. Jerison, H. (1973). Evolution of the brain and intelligence. New York: N.Y.: Academic Press. Lewontin, R. C. (1983). Gene, organism, and environment. In D. S. Bendall (Ed.), Evolution from molecules to men (pp. 273e285). Cambridge: Cambridge University Press. McShea, D., & Brandon, R. (2010). Biology’s first law: The tendency for diversity and complexity to increase in evolutionary systems. Chicago: University of Chicago Press. Nagel, T. (2012). Mind and Cosmos: Why the materialist Neo-Darwinian conception of nature is almost certainly false. New York: Oxford University Press.
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Popper, K. R. (1972). Objective knowledge. Oxford: Oxford University Press. Ruse, M. (1996). Monad to Man: The concept of progress in evolutionary biology. Cambridge, Mass: Harvard University Press. Ruse, M. (2003). Darwin and design: Does evolution have a purpose? Cambridge, Mass: Harvard University Press. Ruse, M. (Ed.). (2009). Philosophy after Darwin: Classic and contemporary readings. Princeton: Princeton University Press. Ruse, M. (2010). Philosophers rip Darwin. The Chronicle of Higher Education, no. March 7. Spencer, H. (1857). Progress: Its law and cause. Westminster Review, LXVII, 244e267. Wilson, E. O. (1975). Sociobiology: The new synthesis. Cambridge, Mass: Harvard University Press. Wilson, E. O. (1992). The diversity of life. Cambridge, Mass: Harvard University Press.
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Evolutionary biology and the question of teleology Michael Ruse Program in the History and Philosophy of Science, Florida State University, FL, 32306, USA
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Teleologydwhat Aristotle called “final cause”dis trying to understand things in terms of the future, as when we ask about the plates on the back of the dinosaur, stegosaurus, and suggest that they might sometime be used to control the internal temperature of the brute. Recently the philosopher Thomas Nagel has argued for a wholesale embrace of teleological thinking in the sciences, particularly the life sciences. I argue that Nagel’s thinking is shoddy and ill-informed, but that in some sense biologists do (with reason) seem drawn to teleological understanding, and so the correct response is not outright rejection of the very idea but a more informed and sympathetic approach to those aspects of nature that seem to call for final cause thinking. Ó 2015 Elsevier Ltd. All rights reserved.
Keywords: Thomas Nagel Teleology Final cause Charles Darwin Natural selection Arms race
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1. Thomas Nagel’s bad book Recently the well-known American philosopher Thomas Nagel published a book, Mind and Cosmos, in which he argued that the thus-far insoluble problems of the biological sciences (especially in the field of evolution) suggest that researchers need to return to teleological explanations. If contemporary research in molecular biology leaves open the possibility of legitimate doubts about a fully mechanistic account of the origin and evolution of life, dependent only on the laws of chemistry and physics, this can combine with the failure of psychophysical reductionism to suggest that principles of a different kind are also at work in the history of nature, principles of the growth of order that are in their logical form teleological rather than mechanistic. (Nagel, 2012, 7) To say that the book was not well received is a bit like saying that Hitler had a thing about Jews. Harvard psychologist Steven Pinker wrote on Twitter of “the shoddy reasoning of a once-great thinker.” Daniel Dennett bluntly said that Nagel’s work “isn’t worth anythingdit’s cute and it’s clever and it’s not worth a damn.” And the Guardian newspaper carried a headline that Nagel’s book was the
most despised science book of 2012 (Chorost, 2013). Perhaps expectedly, the Creationists loved it! Mind and Cosmos is not a great book (Ruse, 2010). Nagel’s knowledge of biology is breathtaking in its nigh-willful superficiality. One suspects that only someone who knew his conclusion before he started his research could argue in so shallow and misleading a fashion. Nagel is no Creationist. One accepts his claim to be an atheist. He does however have a record of praising Creationist booksdmore specifically, he praises books by the so-called Intelligent Design Theorists, what I call “Creationism Lite”dand one senses a shared contempt for and fear of arguments about evolutionary origins. (See Behe, 1996.) Perhaps if we were to identify one single factor for this hostilitydand this is made very clear by Nageldit is that evolutionary thinking belittles the worth of humankind. We are reduced to mere matter in motion and that which makes us somehow special is downgraded and denied. I will not here go into more details; what I would like to do here is turn the tables somewhat and pick up and take seriously Nagel’s claim that we need to take up teleological modes of understanding. Given that I am one who has written critically of Nagel’s book, it may seem odddhypocritical perhapsdthat I would do so. But I am motivated by the ferocity of the reactions to Mind and Cosmos. Bad books appear on a regular basis. Generally such books get little press and they make no waves and are soon forgotten. Why then did Nagel’s book so upset people?
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In part obviously the reaction was because of the Creationism factor. Any book praised by Creationists is going to be disliked and the fact that already Nagel had earlier spoken warmly of Creationist works did not help. I suspect however that there was something about teleology in itself that rattled people. This mode of thought is in some sense considered not just wrong but unclean, and when Nagel started pushing it, emotions were generated and poured forth. Embracing and advocating teleology is a bit like smoking in someone’s living room. People used to do it but they don’t anymore and very much disapprove of those that still do. It is just something that is alien to decent people, or perhaps as with smoking not done now but with a hint of past pleasures and urges that must now be repressed. Nothing like a reformed Magdalene for sanctimonious disapproval. This is the hunch I want to pursue and unpack. Teleology unnerves people because although it is wrong it is still tempting. 2. What is teleology? What does one mean by “teleology,” or more specifically what is a “teleological explanation”? It is a form of explanation that makes reference to causes that can be understood only in terms of the future (Ruse, 2003). To make sense of this definition, contrast teleological explanation with more usual forms of explanation that make reference to “proximate” or “efficient” causes. These latter explanations are in terms of causes that are understood in terms of past or present. So for instance if I say (to take a biological example) the reason why a child has Down’s syndrome is because he has an extra chromosome, I am explaining the physical and psychological nature of the child in terms of some cause that already exists. In a teleological explanation I am explaining in terms of causes that do not yet exist. If I say (to take another biological example) the plates on the back of stegosaurus exist in order to (for the purpose of, have the function of) regulating the heat of the animal, I am talking of what I expect to happen. The stegosaurus has its plates now. Later in the day, the sun heats the brute and then the plates start to radiate heat or to catch the cooling breezes in the air. Note therefore that there is not really a straight analogy between proximate causes and teleological causes. In the former case, you know that the cause exists or existed. In the latter case, the cause may never exist! It could be that the stegosaurus falls of a cliff and never uses its plates for their intended purpose. How then can there be reference to the future if the future never occurs? There are two proffered explanations. One is that teleological explanation occurs in the context of intelligent design. The purpose of the airbags in the automobile is to explode on major contact. It may be that the airbags never are used for this purpose, but the point is that someone at some point thought about what might happen and designed and built them accordingly. The future reference comes because someone thought about it. (This has its roots in the thinking of Plato.) The other explanation is that there is some kind of special force that is future directed. The force may not be a thinking force, but it seeks out phenomena or events in the future. The idea here is rather like the goal-directed system you get in rockets. As the target moves, the rocket adjusts its direction accordingly with the aim of hitting the target. The analogy is not quite exact, because in the case of rockets someonedsome bright engineer from MITddesigned the seeking system. But you get the idea. (This has its roots in the thinking of Aristotle.) 3. Charles Darwin and natural selection I will take seriously Nagel’s claim that he is not a believer, so I accept that he does not see the teleology of biology as literally designed. I presume therefore that he subscribes to some kind of view that has special forcesd“vital forces”dfocused on the future.
This is a view made popular at the end of the nineteenth century by a group known naturally as “vitalists,” led by the German embryologist Hans Driesch who spoke of “entelechies” and the French philosopher Henri Bergson who spoke of “élans vitaux.” (See Bergson, 1907 and Driesch, 1908.) I will not stop here to criticize this view because this was done so often in the last century, but I will agree with the critics that the main problem with vital forces is that they seem not to add to the explanatory mix. Once you have finished talking about DNA and that sort of thing, it really doesn’t seem that adding vital forces adds at all to one’s understanding. However, I will agree with Nagel that there does seem to be something teleological about organism talkdwe do have forward referencedand that this needs explaining. The eye does serve the future purpose of seeing. What I would say is that as always in science we have a metaphor at work here, the metaphor of design. We look at the eye as if designed, even though it may not be, and the reason why we do this is because it does seem as if designed and using the metaphor has incredible heuristic value. In the stegosaurus case, thinking of the plates as if designed for cooling led to all sorts of interesting hypotheses about blood flow, that were later confirmed. Where I part company with Nagel is in thinking that, in the case the design of organisms, we have a more than adequate naturalisticdmechanisticdaccount. This is Charles Darwin’s theory of evolution through natural selection. In his Origin of Species, Darwin argued that population pressures lead to a struggle for existence and (more importantly) reproduction. The successful in the struggle will tend to be different from the unsuccessful and it will be the differences that count. Given enough time there will thus be a natural form of selection. Let it be borne in mind how infinitely complex and close-fitting are the mutual relations of all organic beings to each other and to their physical conditions of life. Can it, then, be thought improbable, seeing that variations useful to man have undoubtedly occurred, that other variations useful in some way to each being in the great and complex battle of life, should sometimes occur in the course of thousands of generations? If such do occur, can we doubt (remembering that many more individuals are born than can possibly survive) that individuals having any advantage, however slight, over others, would have the best chance of surviving and of procreating their kind? On the other hand, we may feel sure that any variation in the least degree injurious would be rigidly destroyed. This preservation of favourable variations and the rejection of injurious variations, I call Natural Selection. (Darwin, 1859, 80e81) Note that Darwin’s mechanism not only leads to change but to change of a particular kind. Organisms will develop end-directed features like hands and eyes, what biologists call “adaptations.” There will be an appearance of design, without need of vital forces or direct interventions by a designer. Blind mechanical law can do everything. It is not so much that final-cause type understanding is now gonedDarwin himself happily talked about final causes and he certainly thought that this involved explaining in terms of the futuredbut that teleology is now subsumed under mechanism (Ruse, 2009). 4. The challenge of history For the Greeks, this would have been the end of the story. They, at least the philosophers, had no real thoughts of development through time. Their world was eternal and essentially unchanging. Historical development comes later and is due in no small part to the biblical narrative, with the movement from Eden to Calvary and later. It was after the Scientific Revolution, during the
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Enlightenment starting at the beginning of the eighteenth century, that people started really to think seriously about development over time. With this came another dimension to the story of teleology. Now the end points, future references, were not to individualsdthe parts of organisms for instancedbut to the end or culmination of time. The question now was about the direction of history and how we can and should interpret the present in terms of what is to come rather than simply in terms of what has passed. Essentially this is the story of progress (Ruse, 1996). It is true of course that one might see history as culminating in humans driving themselves off the edge of a cliff, and in this age of nuclear weaponry and global warming who can gainsay such thinking? But traditionally those thinking about historical development have tended to be optimists, to have endorsed thoughts of progress. In the world of culture, of society, this is the idea that socially and intellectually we humans are improving and will continue to do so. There is an upward pattern to history and we should see stages not only as reflecting what has happened in the past but what was bound to happen in the future. There is change and there is direction and to understand it we need to see where it is headed. In other words we need teleological understanding. And, increasingly through the eighteenth century, people argued that the same is true in the world of organisms. They too show progress, from the simple to the complex, from that lacking in worth to that with fullest worth, from, as it was called, the monad to the man. Some thought that the progress was more conceptual than actual, in the sense of talking of linked development from one to the next that is to say of physical evolution. Others, with greater or lesser enthusiasm accepted the reality of the connections. Either way, as with adaptations, here also teleological understanding is demanded, as we see the futuredin the sense that humans once did not exist and then later they diddas important to understanding as is the past. Cultural progress and biological progress were never two separate ideas. The latter was always an epiphenomenon of the former and often used in a somewhat circular fashion to support the former. Denis Diderot, the French encyclopedist, was a pioneer. “Just as in the animal and vegetable kingdoms, an individual begins, so to speak, grows, subsists, decays and passes away, could it not be the same with the whole species?” (Diderot, 1943, 48, quoting On the Interpretation of Nature, 1754) He made no bones about seeing a link between his social views and his scientific speculations. “The Tahitian is at a primary stage in the development of the world, the European is at its old age. The interval separating us is greater than that between the new-born child and the decrepit old man” (Diderot, 1943, 152, quoting Supplement to Bougainville’s Voyage, 1772). Later in the century Charles Darwin’s grandfather, the physician Erasmus Darwin, fell into the same pattern. Imperious man, who rules the bestial crowd, Of language, reason, and reflection proud, With brow erect who scorns this earthy sod, And styles himself the image of his God; Arose from rudiments of form and sense, An embryon point, or microscopic ens! (Darwin, 1803, 1, 11, 295e314)
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Surely this all came to an end with Charles Darwin? Evolution was now far more than something merely riding on the back of the idea of cultural progress. Interestingly, however, its connection with cultural progress was not severed. Evolutionists continued to be thoroughly soaked in thoughts about cultural progress and they continued to see this reflected in the history of organic life. This was true of Darwin: “The inhabitants of each successive period in the world’s history have beaten their predecessors in the race for life, and are, in so far, higher in the scale of nature; and this may account for that vague yet ill-defined sentiment, felt by many palæontologists, that organization on the whole has progressed.” (Darwin, 1859, 345) And this kind of thinking continued right down into the twentieth century. There have been those, like the late Stephen Jay Gould, who attacked the whole notion of biological progress. He wrote of biological progress as “a noxious, culturally embedded, untestable, nonoperational, intractable idea that must be replaced if we wish to understand the patterns of history” (Gould, 1988, 319). He argued that there is nothing inevitable about the emergence of humans. Making joking reference to the asteroid that hit the Earth 65 million years ago and wiped out the dinosaurs, making possible the age of mammals, he wrote: “Since dinosaurs were not moving toward markedly larger brains, and since such a prospect may lie outside the capabilities of reptilian design., we must assume that consciousness would not have evolved on our planet if a cosmic catastrophe had not claimed the dinosaurs as victims. In an entirely literal sense, we owe our existence, as large and reasoning mammals, to our lucky stars” (Gould, 1989, 318). Actually, as we shall see, Gould’s full position on the subject was much more complex than a simple denial of progress. But Gould apart, the fact is that many, perhaps most, continued to believe in such progress. Today’s most distinguished living evolutionist, Edward O. Wilson of Harvard University, is open in his fervent belief in biological progress. “The overall average across the history of life has moved from the simple and few to the more complex and numerous. During the past billion years, animals as a whole evolved upward in body size, feeding and defensive techniques, brain and behavioral complexity, social organization, and precision of environmental controldin each case farther from the nonliving state than their simpler antecedents did” (Wilson, 1992, 187). Adding: “Progress, then, is a property of the evolution of life as a whole by almost any conceivable intuitive standard, including the acquisition of goals and intentions in the behavior of animals.” (See also Wilson, 1975.) Others agree. In his great popular overview of modern evolutionary thinking, The Blind Watchmaker (1986), Richard Dawkins refers to Harry Jerison’s (1973) notion of an Encephalization Quotient, this being a kind of universal animal IQ, that works from brain size and subtracts the gray matter simply needed to get the body functioningdwhales necessarily have bigger brains than shrews, because they have bigger bodies. What counts is what is left when you take off the bodyfunctioning portion. Thus measured, humans come way out on top, leading Dawkins (1986, 189) to reflect: “The fact that humans have an EQ of 7 and hippos an EQ of 0.3 may not literally mean that humans are 23 times as clever as hippos!” But, he concludes, it does tell us “something.” 5. Problems with progress
Explicitly, Erasmus Darwin tied in this vision of the organic world with his hopes and beliefs about the social world: the idea of organic progressive evolution “is analogous to the improving excellence observable in every part of the creation; . such as the progressive increase of the wisdom and happiness of its inhabitants” (Darwin, 1794e96, 509).
Why would anyone worry about biological progress? Couldn’t you say that although it has the odor of teleologydthe course of evolution is directed to the end point of humankinddthe system is just as mechanistic as adaptation, something else with the odor of teleology but entirely mechanistic? In fact, the same process is at work in both cases, natural selection in the short term for
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adaptation and natural selection in the long term for progress. As it happens, it is pretty clear that Gould’s objections to biological progress were more social than scientific. He believed in social progress but thought biological progress a barrier to its fulfillment. Too easily biological progress is used to justify racismdblacks, Asians, Jews down the scale and white Anglo-Saxons at the topdand he fought against his all of his life. But this kind of thinking aside, the fact is that many find beliefs in biological progress something of an embarrassment. At the specific level, because whatever Darwin himself may have thought, it seems that his theory quite undermines thoughts of biological progress. On the one hand, natural selection is relativistic. It is not a tautology but it does say that what is of adaptive advantage in one situation is not necessarily of adaptive advantage in other situations. A darkskinned mouse is camouflaged on clay soil whereas a lightskinned mouse is camouflaged on sandy soil. On the other hand, the variationsdthe raw building blocks of evolutiondare random in the sense of not occurring according to need. There is no direction in their nature. This fact too seems to tell against inevitable upwards climb. At the general level, seeing the history of life on Earth as moving up towards the best of all possible organisms, Homo sapiens, is to put value judgments right up front of one’s science. And this is considered incompatible with good science. Since the Scientific Revolution, nature has been seen simply as matter in motion, without point, without purpose. Hence professional science itself must be value free. It cannot promote things one wants. Only things as they are. In the words of Karl Popper (1972), science is “knowledge without a knower,” meaning that human interests are excluded. Thus although there may be belief in biological progress, the tendency is to downplay it or exclude it from explicit discussion. 6. Naturalizing progress Or to argue that it is no longer a value laden notion! As in the case of final causes with respect to individual features (adaptations), the hope is that the teleology of history can be put on a happy mechanical foundation. How can this be done? God cannot enter into the picture. Neither can vital forces. Natural selection itself, or some equally naturalistic alternative, must do the explaining. Part of the trick will be giving a definition or characterization of what is being produced, something that humans have more than any other organisms. One can hardly simply say “human-like features” because that just gets you into a circle. They must be features that we in some sense judge desirable, although the judgment itself cannot be part of the science. Generally the move is towards some kind of complexity. Darwin led the way here. In the third edition of the Origin (1861) he admitted that “naturalists have not defined to each other’s satisfaction what is meant by an advance in organisation.” However, he was prepared to make a suggestion of his own. Amongst the vertebrata the degree of intellect and an approach in structure to man clearly come into play. It might be thought that the amount of change which the various parts and organs undergo in their development from the embryo to maturity would suffice as a standard of comparison; but there are cases, as with certain parasitic crustaceans, in which several parts of the structure become less perfect, so that the mature animal cannot be called higher than its larva. Von Baer’s standard seems the most widely applicable and the best, namely, the amount of differentiation of the different parts (in the adult state, as I should be inclined to add) and their specialisation for different functions; or, as Milne Edwards would express it, the completeness of the division of physiological labour. (Darwin, 1861, 133)
7. Arms races How are you going to get this complexity by natural means? Again Darwin comes to our aid. Basically you argue that selection leads to competition and the more subtle or sophisticated or complex will win out in the end. Intelligence is at the top of complexity and so humans come out top. If we look at the differentiation and specialisation of the several organs of each being when adult (and this will include the advancement of the brain for intellectual purposes) as the best standard of highness of organisation, natural selection clearly leads towards highness; for all physiologists admit that the specialisation of organs, inasmuch as they perform in this state their functions better, is an advantage to each being; and hence the accumulation of variations tending towards specialisation is within the scope of natural selection. (Darwin, 1861, 134) In the twentieth century, this kind of thinking was refined and the discussion was cast in terms of “arms races.” Lines of organisms compete and improvement occursdthe prey gets faster and so does the predator. The person who really developed this notion was Julian Huxley. Likening biological evolution to the competition between nations in preparation for war, and making reference (writing in 1912) to the naval build-up between Germany and Britain, Huxley wrote: “The leaden plum-puddings were not unfairly matched against the wooden walls of Nelson’s day.” He then added that today “though our guns can hurl a third of a ton of sharp-nosed steel with dynamite entrails for a dozen miles, yet they are confronted with twelve-inch armor of backed and hardened steel, water-tight compartments, and targets moving thirty miles an hour. Each advance in attack has brought forth, as if by magic, a corresponding advance in defence.” Explicitly, Huxley likened this to the organic world, for “if one species happens to vary in the direction of greater independence, the inter-related equilibrium is upset, and cannot be restored until a number of competing species have either given way to the increased pressure and become extinct, or else have answered pressure with pressure, and kept the first species in its place by themselves too discovering means of adding to their independence” (Huxley, 1912, 115e16). And so finally: “it comes to pass that the continuous change which is passing that through the organic world appears as a succession of phases of equilibrium, each one on a higher average plane of independence than the one before, and each inevitably calling up and giving place to one still higher.” Richard Dawkins picks right up on this sort of thinking. In a paper co-authored with fellow biologist John Krebs he writes that even “if modern predators are no better at catching prey than Eocene predators were at catching Eocene prey, it does at first sight seem to be an expectation of the arms race idea that modern predators might massacre Eocene prey. And Eocene predators chasing modern prey might be in the same position as a Spitfire chasing a jet” (Dawkins & Krebs, 1979, 490). In other words, in Dawkins’s happy Darwinian world, it all comes out right in the end. As in the military world, weaponry has become increasingly electronic, and those organisms with the biggest on-board computers win out. 8. Niches A second Darwinian approach can be found in one of the many essays that Stephen Jay Gould penned for Natural History. This may seem strange, because we have seen how he argued against biological progress. However, as I have pointed out, it is clear that this opposition was more political than
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epistemological, and if you look at Gould’s overall corpus, you find that throughout he had yearnings for some kind of improving development with humans winning out in the end. Think about ecological nichesdlike the shelter provided by trees or the safety of burrows underground. One might say that, thanks to natural selection, organisms are constantly looking and prodding to find new niches and, when they do, they enter and exploit them. The first animals to get up to and survive on dry land found a whole new area in which they and their descendents could live and thrive. Culture can be described as one such niche, the niches that humans have found and entered. If not us, was it not predictable that someone on Earth would find and enter the niche? Why should this not happen repeatedly, if not here on Earth (because you might say that we have now blocked the entrance) then elsewhere in the universe? Note that selection here is doing the work, but it is not doing it by one organism beating out another and thus proving its superiority. The superiority if such there be comes from the niche itself and rather confers this on its inhabitants. So there are no longer the obvious opportunities for racism and sexism. In an essay on the search for extraterrestrial life, Gould wrote: “I can present a good argument from “evolutionary theory” against the repetition of anything like a human body elsewhere; I cannot extend it to the general proposition that intelligence in some form might pervade the universe” (Gould, 1985, 411). He then went on to quote the leading twentieth-century evolutionist Theodosius Dobzhansky, writing in a textbook with other major evolutionists: “Granting that the possibility of obtaining a man-like creature is vanishingly small even given an astronomical number of attempts. there is still some small possibility that another intelligent species has arisen, one that is capable of achieving a technological civilization” (412). About this passage, Gould commented: “I am not convinced that the possibility is so small.” He then gave an argument that evolutionary convergence (where two different lines evolve essentially similar adaptations to survive and reproduce) suggests that even though major intelligence has arisen but once on this earth, it is quite possible that elsewhere in the universe it has arisen quite independently. Conscious intelligence has evolved only once on earth, and presents no real prospect for reemergence should we choose to use our gift for destruction. But does intelligence lie within the class of phenomena too complex and historically conditioned for repetition? I do not think that its uniqueness on earth specifies such a conclusion. Perhaps, in another form on another world, intelligence would be as easy to evolve as flight on ours. (412) This argument has been picked up (apparently independently) and promoted by the paleontologist Simon Conway Morris, who (as a Christian) is very keen to argue for the inevitability of the appearance of humans. He argues that only certain areas of what we might call “morphological space” are welcoming to life forms (the center of the sun would not be, for instance) and that this constrains the course of evolution. Again and again, as Gould argued, organisms take the same route into a pre-existing niche. The saber-toothed, tiger-like organisms are a nice example, where the North American placental mammals (real cats) were matched right down the line by South American marsupials (thylacosmilids). There existed a niche for organisms that were predators, with cat-like abilities and shearing/stabbing-like weapons. Darwinian selection found more than one way to enter itdfrom the placental side and from the marsupial side. It was not a question of beating out others but of finding pathways that others had not found.
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Conway Morris argues that, given the ubiquity of convergence, we must allow that the historical course of nature is not random but strongly selection-constrained along certain pathways and to certain destinations. Most particularly, some kind of intelligent being was bound to emerge. After all, our own very existence shows that a kind of cultural adaptive niche existsda niche that prizes intelligence and social abilities. If brains can get big independently and provide a neural machine capable of handling a highly complex environment, then perhaps there are other parallels, other convergences that drive some groups towards complexity. Could the story of sensory perception be one clue that, given time, evolution will inevitably lead not only to the emergence of such properties as intelligence, but also to other complexities, such as, say, agriculture and culture, that we tend to regard as the prerogative of the human? We may be unique, but paradoxically those properties that define our uniqueness can still be inherent in the evolutionary process. In other words, if we humans had not evolved then something more-or-less identical would have emerged sooner or later. (Conway Morris, 2003, 196)
9. Complexity just happens A third suggestion finds hints in Darwin but it is not very Darwinian, inasmuch as it does not rely on natural selection. It basically says that there is a natural tendency to complexity and over time you will get what you want. In one of his early notebooks Darwin wrote: The enormous number of animals in the world depends of their varied structure & complexity. d hence as the forms became complicated, they opened fresh means of adding to their complexity. d but yet there is no necessary tendency in the simple animals to become complicated although all perhaps will have done so from the new relations caused by the advancing complexity of others. d It may be said, why should there not be at any time as many species tending to dis-development (some probably always have done so, as the simplest fish), my answer is because, if we begin with the simplest forms & suppose them to have changed, their very changes tend to give rise to others. (Barrett et al. 1987; Notebook, E, 95e6) Of course, for Darwin, selection was always hovering, so he would have seen this process connected to change towards adaptive advantage. A purer version, if we might so describe it, can be found in the thought of Herbert Spencer. To characterize the phenomenon of complexity, something he admitted he got from the Naturphilosoph Friedrich Schelling via the writings of the poet Samuel Coleridge, Spencer introduced two terms which have had a very long shelf life. Simple organisms (or states of affairs generally) are “homogeneous. Complex organisms (or states) are “heterogeneous.” The course of progress therefore is from the homogeneous to the heterogeneous. As he developed his thinking around the time that Darwin published the Origin, Spencer fell more and more under the spell of physics. This led to his full-blown theory of “dynamic equilibrium.” He argued that organisms, or a state, exist in a balancedworking normally, with everything in equilibria. Then somethingdquite possibly something from outsidedacts to upset the balance and things get into play. They are striving always to regain equilibrium, just as a ball bearing at the bottom of a bowl, if disturbed, will naturally tend back down to the center and to regained equilibrium. Eventually this balance will be achieved, but
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it will be a new balance, higher than before, and with a greater heterogeneity than before. Backing all of this, Spencer gave a kind of metaphysical principledone that may or may not have been behind the notebook passage of Darwin quoted abovedthat causes always proliferate in several effects but never conversely. So complexity emerges naturally. “Every active force produces more than one change e every cause produces more than one effect” (Spencer, 1857, 32). More recently, in his book Full House (1996), Gould argued that there is certainly no necessary, selection-driven process of progressive evolution leading to greater complexity. However, he did at the same time agree that the natural course of events would lead to ever-more complex organisms. These ideas have been picked up and developed at some length recently in a new book by two academics at Duke University, one a biologist (Daniel McShea) and the other a philosopher (Robert Brandon). In Biology’s First Law: The Tendency for Diversity and Complexity to Increase in Evolutionary Systems, they offer a very Spencerian vision of the evolutionary process (McShea & Brandon, 2010). They call their law the “zeroforce evolutionary law,” or ZFEL. It is formulated as follows: “In any evolutionary system in which there is variation and heredity, in the absence of natural selection, other forces, and constraints acting on diversity or complexity, diversity and complexity will increase on average.” What do McShea and Brandon mean by complexity? Certainly nothing to do with natural selection as such. They say that complexity is “a function only of the amount of differentiation among parts within an individual.” Elsewhere they say ““complexity” just means number of parts types or degree of differentiation among parts.” They are very careful to specify that this has nothing to do with adaptation. Indeed they say “in our usage, even function less, useless, part types contribute to complexity. Even maladaptive differentiation is pure complexity.” How could this complexity come about? It all seems to be a matter of randomness, meaning not that there are no causesdwith orthodox Darwinians they would agree that the building blocks of evolution (mutations) have physical causesdbut that there is no direction in the nature of the building blocks or in what happens to them once they appear. With Gould, and I think with Spencer, they simply believe that over time more and more things will happen and pieces will be produced and thus complexity will emerge. It is the inevitability of the drunkard falling into the gutter.
have their costs, namely the need of large quantities of high-grade fuel (the bodies of other animals) and there are times when this might not pay. In the immortal words of the late John J Sepkoski: “I see intelligence as just one of a variety of adaptations among tetrapods for survival. Running fast in a herd while being as dumb as shit, I think, is a very good adaptation for survival” (Ruse, 1996, 486). The niche suggestion is clever and may have some real worth. However, as critics of Darwinism like geneticist Richard Lewontin (1983) point out non-stop, niches do not exist in splendid isolation waiting to be found. They are as much made as discovered. The niche for insects at the tops of Brazilian junglesdapparently a very rich home for much lifedobviously would not exist were there no trees. The point is not whether humans have evolved, because obviously we have. The question is whether we would necessarily evolve given the evolutionary processdeither here or somewhere else in the universe. Who is to say that there are not many other possible niches that would produce something quite different from consciousness but as effective? Don’t ask me what they are, because the whole point is that I don’t know! I am just asking why they are ruled out. Finally the natural tendency to complexity. This may well be true and it may be important. Darwin is surely right about the way in which it leads to a diversity of organisms. But again I am not quite sure why humansdor human-like beingsdshould emerge. Perhaps they will. Perhaps they won’t. The point is that without some stronger reason, like those supplied by the Greeks, you might be waiting a long time for nothing. And the Greek solutions are not acceptable in modern science. 11. Envoi All of this may leave the reader somewhat dissatisfied. There has to be some reason why humans, the best of all organisms, emerged. And yet, given mechanism, there is no satisfactory answer or prospect of such an answer. Which brings us back to Thomas Nagel. I suggest that for all of the inadequacies of his own positiondit was reprehensible to argue in the shoddy fashion to be found in Mind and Cosmosdhe has put his finger on a sore point. Evolutionists want teleology but they cannot have it. And perhaps that goes some way towards explaining the vehemence of their reactions to his book.
10. Close but no cigar References So, pulling back, what do we say about historical direction and teleology? Interesting and stimulating though the various naturalistic proposals may be, nothing quite works as well and as definitively as one might like. In a way, the whole talk about complexity is problematic. And even if one solved the general issues, one might query whether any proposal would unambiguously classify humans as the top organisms. One of the most interesting things to emerge from the Human Genome Project was just how few genes are needed to produce so much. What about consciousness? Is that complex or simple? Note that this is not to say that humans are not special or that they should not be valued over all other organisms. I certainly value humans over warthogs. It is just a matter of finding characteristics of humans that do not end in circularity and that would be produced by evolutionary processes. Analogously, all of the mechanisms for producing human-like beings are suggestive but hardly definitive. Most Darwinians accept arms races although there are critics. The fossil record does not suggest that predator-prey encounters always improve speed. But even if you accept their importance, whether they will necessarily produce intelligence is another matter. So it is hard to claim that in some sense being humanlike is absolutely good. Even brains
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