 We paleontologists would like to claim Steven J. Gould as our own. However, the diversity of evolutionary phenomena and the implications of this theory have lured him away at times to other disciplines. He teaches geology, biology, and the history of science at Harvard University. Dr. Gould does elegant research and writes eloquently and convincingly on more than one level. On the one hand, his journal articles on the course and mechanisms of evolution have been a major contribution to evolution theory. In particular, articles with colleague Niles Eldridge on the idea of punctuated equilibrium have sparked the heated and healthful debate of this last decade concerning evolution theory. At a different level and perhaps more significant for us at this conference Steven J. Gould has been the scientist who has been most willing, patient, and most effective in articulating to the non-specialists the implications of evolution theory for all of us. His books, The Mismissure of Man Ever Since Darwin and The Panda's Thumb, while revealing the amazing success of evolution theory and explaining an amazing variety of phenomena, remind us that scientists have always derived and applied their ideas within personal political and cultural contexts. Those of us who subscribe to Natural History magazine find ourselves turning to his column even before the gorgeous photographs in that magazine. We turn to see what Steven Gould will tell us this month about this view of life. Steven Gould. Sigmund Freud in a famous statement talking about the role of science and the transformation of human thought wrote that humanity has in the course of time had to endure from the hands of science. I got to get used to this delayed auditory feedback. I sound like Lou Gehrig in Yankee Stadium. It's had to endure from the hands of science two great outrages upon its naive self-love. The first was when it realized that our earth was not the center of the universe but only a speck in a world system of a magnitude hardly conceivable. The second was when biological research robbed man of his particular privilege of having been specially created and relegated him to a descent from the animal world. Now Freud of course here talks about the two revolutions that we associate first with the name of Copernicus Newton and Galileo and secondly with that of Darwin. I think the curious aspect of both those revolutions is that one today is thoroughly accepted and understood namely Galileo's. The other is not yet of course that has not always been so. There was time when Galileo's cosmology was as controversial as Darwin in biology and that of course arises because Galileo was not engaged in an abstract debate about lunar motion. Very much more was at stake. In general and in the abstract was the very position of the earth and human beings in the cosmos and much more specifically because the older cosmology did serve a political and social function in Galileo's time. After all the idea of a small universe with the earth as its center and the power relationship set up that way with the earth in the middle and man on the earth and things going around the earth and subordinate to it was seen as a sign of social stability on earth and just as you had that formation of the cosmos so too on earth did you have the king in the center with the lords going around or the lord in the center and the serfs going around it was a model indeed of social stability and therefore the promulgation of a totally different cosmology was quite a challenge. I think the best example I can give pictorially of the enormous effect of Galileo's revolution will be shown in the first two slides. Now we're going to have to try in this great darkening experiment. Do I push this? Oh boy that's big. This famous painting which hangs in the Cathedral of Santa Maria del Fiore in Florence the great practically under Brunelleschi's dome and it shows the pre-Galian world. It shows the older completely contained cosmology. This is the early 15th century painting of Dante in his world. The whole universe is encompassed in the single picture. There's Dante and the city of Florence in the center. To his right is Brunelleschi's great dome of the cathedral and to his right is Purgatory leading up to Paradise and further to his right going in the other direction of the universe in the single slide. This unfortunately is cut off and it's not a picture of the whole painting but I think you can observe up above the beginnings of concentric circles and in those concentric circles run the seven planets of the Ptolemaic system that is the five visible planets plus the earth and the moon and then up in the little corners of the painting which you can't see because the slide doesn't show them in the realm of the fixed stars. The entire universe with Florence at its center is encompassed in this pre-Galian cosmology. Well you then go to another great church in Florence the church of Santa Croce and you see the totally different universe that Galileo bought. Here in fact is Galileo's tomb in the church of Santa Croce and he sits I don't know a pointer and I think it's hard to see but as you see Galileo sits there in the center he looks upward to the universe and his hand is resting on a tiny little globe representing the earth and there in his crushing symbolism as you could ask is the transformation of human thought wrought by that great revolution. The Darwinian revolution of course was equally upsetting and here also in metaphorical guise is my favorite illustration of that. This actually happened this is not a trick slide this is the campus of Stanford University after the San Francisco earthquake of 1906 and we see the statue of Louis Agassiz the last great scientific creationist of America who died unconverted in 1873. Symbolic of the destruction of his world system up ended in a skew on that campus. Next slide is a close-up of the same. It's a wonderful story about this which probably isn't true but deserves to be maybe it is. The president of Stanford University at the time was the great Darwinian ectheologist David Star Jordan. Now Agassiz had also been an ectheologist as a student of fishes and Jordan recognizing his compatriot said apparently when he saw this that he had always thought better of Agassiz in the concrete than in the abstract. Nonetheless although the Galilean cosmology is fully accepted Darwin's worldview has not reached the same level of public acceptance. The most striking example today being of course that political campaign to subvert the first amendment by inserting into schools a very rigid fundamentalistic version of religion masquerading as the pseudo science of creationism. Be that as it may it's certainly an illustration of the tensions that still beset us. I think the lack of acceptance in many quarters of Darwinian evolution is not because evolution is any less well supported than the Galilean cosmology. Of course there is no certainty in science only in logic and mathematics which doesn't deal with the empirical world and therefore can have its kind of certainty but the fact of evolution now I am distinctly not talking about theories of the mechanisms of evolutionary change which are appropriately battlegrounds of argument as they should be. I'm talking about the mere statement that animals are connected by ties of genealogical descent that's about as well supported as any great finding in science. If you'll accept my definition of fact it's I think a good vernacular definition and the only one we could use in science namely conclusions sufficiently well supported that it would be perverse to withhold one's provisional assent I think we could define evolution as as good a fact and nature is anything we know. So if evolution is no less well supported than the Galilean cosmology why is there so much argument about it? I think there are two major reasons we could advance one is the simple one which is undoubtedly part of the truth that we've had three centuries or more to accommodate to Galileo but only one to accommodate to Darwin and it takes a while. At the great Darwinian centennial celebrations of 1959 the great American geneticist H.J. Muller delivered a keynote address with a rather sardonic title he called it 100 years without Darwin are enough maybe it takes that long however I think the main reason why we've been reluctant is anyway I can I guess you said I couldn't get lights back on but anyway I can get slides off we really don't have to look at Agassi upside down while I I'm going to talk now for 10 or 15 minutes before any slides I guess we're just going to get more darkness all right I'd much rather see you but if we can't get light I shall talk to this sea of darkness before me even darkness which might be felt I think the other reason why it's so difficult to accept Darwinian evolution is that in a way it's more threatening even the Galilean cosmology it's closer to us the Darwinian heritage deals directly as the Galilean cosmology did not with that great question that Huxley called man's place in nature this lecture will therefore be about what evolutionary theory says in my opinion about that monumental issue of man's place in nature and it'll be in two parts one much longer than the other so when an hour is passed I haven't gotten to the second don't panic it's much shorter first generally what modern evolutionary theory has to say about the nature of the biological world and secondly a few specific comments about the role of human evolution and our origin within that scheme now I think talking on the general issue first everyone would admit that we and culture have biases and expectations the conventional heroic view of science which I displayed myself in the first two slides points out how science can challenge the conventional biases and expectations of western culture and often in a powerful way reverse them this is true indeed but the dialectic work science though it can fight and challenge the biases of western thought is also embedded within them and tends to reflect them and much of evolutionary thinking is tend to reflect a whole set of what I consider some of the greatest biases of western thought four of which I'd like to discuss today because I think they've been central in the misunderstanding of evolution and in our unwillingness to come to terms with Darwin's world when we understand the nature of these pervasive biases of western thought I think it's also easy to see what kind of a revolutionary Darwin was and why his theory has been so difficult to accept even by the millions of people who are quite content to accept the fact of evolution itself and I think these four great biases of first of all progressionism or the idea that the history of change on the earth is somehow a history of progressive alteration leading to that last great product of the creation us and that if we're to look at evolution it will have those ladder-like properties of progressive cosmic advance now linked to that bias is a general preference within that progressionist system to see at least since Darwin's time those changes being gradual in nature so that progress is achieved through a long and laborious set of steps up that ladder a third important bias is determinism by which I mean the general idea that events have causes and are somehow right in this world and the banning of chance as a causal agent or as an agent of change in the world we're very uncomfortable with that notion we remain so and the fourth great bias is what I call adaptationism by which I do not narrowly mean Darwin's theory of natural selection by any means which is in part about adaptation by adaptationism I have in mind the larger world view that things are right in this world that things fit that organisms fit in their environments and environments fit into the earth and the earth is somehow right now clearly all those four views progressionism gradualism determinism and adaptationism go together to form a set of comforts and hopes to form a world that we would like to accept one that indeed in which we would feel quite comfortable and I think the best way to illustrate those four biases which I think have been fundamental in retarding our understanding of what it is that Darwin was trying to say and our understanding of evolutionary theory in general I think I can illustrate all four of those biases from my favorite source of quotations in Western literature after the bible namely Alexander Pope's essay on man which I think stands as a great document of 18th century thought and the matrix of thought out of which our hopes have emerged and those hopes that continue to impress themselves upon our understanding of evolution let me then illustrate all those four biases in the lines that form the end of the first part of Alexander Pope's essay on man first on the subject of progress and gradualism and invoking the old theme of the chain of being pope talks about the arrangement of organisms in this hierarchy from amoeba to man and he writes in heroic couplets far as creations ample range extends the scale of sensual and mental powers ascends mark how it mounts to man's imperial race from the green myriads and the peopled grass I suppose those words rhymed back then and then talking more explicitly about the chain of being vast chain of being which from god began nature's ethereal human angel man beast bird fish insect what no I can see no glass can reach glass being microscope from infinite to thee from thee to nothing from nature's chain whatever link you strike tenth or ten thousandth breaks the chain alike and again in the in that couplet you can see the political usages of biases and worldviews that every creature and every human being has his appropriate status on the earth and the poor peasant the ten thousandth link is as essential and where he ought to be is the king on the first link the very next lines pope goes on to invoke in the usual metaphor what the world would be like if determinism did not rule the cosmos and he invokes that equation of randomness with chaos which is so fundamentally incorrect but is so often done and he writes let earth unbalanced from her orbit fly planets and suns run lawless through the sky let ruling angels from their spheres be hurled being on being erect and world on world heaven's whole foundation to their center nod is node and nature trembled to the throne of god a little bit before he talks about that adaptationist view that things are fundamentally right and things are in their proper position on this earth in a wonderful set of lines where he says that although some men may be dissatisfied with the acuity of their senses those senses are a portion to our proper status on this earth and he starts why has not man a microscopic eye for this plain reason man is not a fly that requires a little exegesis it was believed incorrectly at that time that the compound eye of flies and other insects allowed them to see microscopically the small objects of their dimensions that's wrong of course say what the use were finer optics given to inspect a mite not comprehend the heaven and then talking about touch or touch if tremblingly alive all or to smart and agonize at every pore then my favorite line about smell or quick a fluvia darting through the brain dive arose in aromatic pain and then on sound reminds me of persil played by 20 trumpets if nature thundered in his opening ears and stunned him with the music of the spheres how would he wish that heaven had left him still the whispering zephyr and the pearling rill and finally the famous lines at the end of this first epistle of the essay on men where all the biases have brought together and united again with the political point all nature is but art unknown to thee all chance direction which thou canst not see all discord harmony not understood all partial evil universal good and spite of pride and erring reason spite one truth is clear whatever is is right and that is the matrix of our hopes the matrix of the biases that darwin's theory challenges modern evolutionary theory leads us to question all four of these biases and i think that this is largely why it has been so difficult for us to accept it darwinism as an evolutionary theory is particularly hard to swallow because it challenges very strongly at least two of these biases darwin himself did and here i do have to make that explicit distinction i spoke about very briefly before between the fact of evolution and theories to explain its mechanism what i call the fact of evolution remember my own definition of that term namely that organisms are tied by genealogical descent is as well established anything in science theories that explain how it is that evolutionary transformations occur our theories of evolutionary mechanism darwin tried to do two very different things in his life first to establish the fact of evolution in endeavor in which he was abundantly successful and second to propose a theory called the theory of natural selection to explain its mechanism and i'm talking about the implications of the theory of natural selection darwin was very explicit about these two very separate goals he wrote for example in the descent of man i had two distinct objects in view firstly to show that species had not been separately created and secondly that natural selection had been the chief agent of change the mere fact of evolution is hard enough for many people to swallow but there are congenial versions of evolutionary mechanisms that support all four of the great biases that i've identified for example lamarckism which is an evolutionary theory that accepts progressionism gradualism determinism and adaptationism as part of its mechanism i think it's one of the main reasons why lamarckian evolutionary theories remain so popular long after the genetic rationale for them and disappeared and why they keep recurring they match our hopes and what we would like to believe but darwinian theory the theory of natural selection attacks those biases darwin's personal views attacked two of them and the expansions and extensions of darwinian theory that we recognize today attack all four of them let me talk first about the two that darwin himself explicitly attacked first the idea of progress theory of natural selection contrary to some popular beliefs is not a theory about cosmic directed predictable universal progress it is a theory about universal adaptation it may talk about progress in that very restricted sense of improvement in local environments but that's not what the bias of progressionism is about the bias of progressionism is about that notion of universal cosmic advance darwin's theory states that organisms produce more offspring than can possibly survive that organisms vary that some of that variation is inherited and that as a result on average those survivors among the few who can make it will be those better adapted to local environments it is a theory of adaptation to changing local environments and that's all it is darwin did not deny that there are certain lineages within which we might in some vernacular sense choose to talk of progress the history of vertebrates might be one but he delighted in pointing out that for each vertebrate that we would choose to call complex living within it are 10 species of parasites some so morphologically degenerate that they little more than bags of reproductive tissue that are doing just as well in terms of their adaptations to their local environments and have just as good prospect of evolutionary success more over evolution as darwin often said though not with this metaphor is not a ladder of progress but a complexly branching and ramifying bush the tree of life the tangled bank in his words reflecting the theme that evolution is adaptation to local environment and not cosmic progress i want now to show a series of slides that illustrate the public misunderstanding of this fundamental aspect of darwinian theory these slides are funny and in the sense they're meant to be but they also under are meant to reflect that serious point of our misunderstanding of this fundamental point about darwinian theory so them off again pick this up from the back cover of tv guide while ago it's didn't going to do unless we can see the words that are on the top and there we have doral's theory of evolution now clearly they're not trying to tell you that their cigarette has changed over 75 years but that it's gotten better and there is that conflation of evolution with progress i'll now show you several other advertisements of the same themes again we're going to have to drop it because it's the words at top that count not pictures this is when the good people at folksvoggan invented the rabbit and they put out a promotional pamphlet called folksvoggan's theory of evolution first this place was not made for visual what this shows you can't see it at the bottom is the origin of the species and the bug is born in a carboniferous coal forest in the next slide in a Jurassic swamp we have and i'm going to need the top top please we have a higher form of beetle and finally and appropriately in a cabbage patch you'll see the beetle gives birth to a rabbit at least that's at least that's not gradual change i'm happy to announce just one more from the automotive industry evolution moves selectively towards perfection we're told is the mondial aid is introduced let me show you the one advertisement i've ever seen that got it right this is from the people at wang computers a couple years ago the natural selection a mini computer that adapts to changing environments and that is just right what's next oh yeah sure every evolutionist has his favorite example of what darwinian theory really is talking about namely local adaptations peculiar local adaptations i'm going to show you my favorite examples that looks for all the world like a fish mounted on the rear end of a clam but it isn't in fact that fish like structure is a decoy it's part of the clam itself the body of the fish is in fact the marsupium or the brood pouch of this clam and is filled with filled with larvae of the female clam the eye spot the fins are part of the mantle of the surrounding skin of the fish now if you ask why it is that a clam would build a fish on its rear end you look at the unusual life cycle of these freshwater mussels and you get the answer uniquely among clams the larvae of these freshwater mussels must become parasitic on the gills of fish therefore the structure has been built by local natural selection one assumes fishes come by to take a bite or out of curiosity or whatever the clam since the body of that fish houses the larvae shoots the larvae at the fish some of which attach to the gills and begin their free ride into the next generation now this is an exquisite local adaptation but in no sense of the term can i say that this clam is better than an oyster or a scallop or a quail hog or any other kind of claim it is just a clam exquisitely adapted to some peculiarity of its local lifestyle and environment let me just give you one further example that also looks like a fish it also has an eye and fins and a tail you will have guessed by now that it too is not a fish so this particular one is at least part of a fish it is in fact the lure of an angler fish angler fishes detach the first dorsal fin spine move it over their head and have evolved lures at the end of that dorsal fin spine most are not as complex as this some look like worms some are phosphorescent particularly for those angler fish that live in the sea below the level at which light can penetrate but this particular angler fish mounts a decoy fish and literally goes fishing with it but again you wouldn't want to say this angler fish is better than a shark is cosmically improved it is again one creature locally adapted in a peculiar and exquisite way to its own environment of floating in the ocean and so that's what Darwinism is about it's about local adaptation it's about bushes and luxuriant branching it's not about ladders of progress to humanity now the second of the four biases which Darwin rejected was adaptationism even though there are rather strict versions of Darwinian theory today that are very much more adaptationist than Darwin was himself and by adaptationism remember I don't just mean the theory of natural selection but the idea that everything is best in this perfect world of ours a Darwinism could not have been a strict adaptationist so this is often not appreciated if only because the main evidence for evolution is and must be the imperfections of nature if nature were perfect if every organism were optimally constructed for its environment then it shows no history the great principle for the reconstruction of history is that you must have inherent within structures imperfections that record the pathways of historical change if structures are perfect they may have been evolved that way or they may have been created that way and there's no particular way to tell it's through the imperfections that mark courses of historical change that we see the fact of evolution and then therefore Darwin displaying the evidence for evolution so masterfully could not have been this kind of strict paleon adaptationist he understood perfectly well that the signs of evolution were the imperfections of history all the classical evidences for evolution the biographic arguments about the Galapagos why if the world were perfect should the Galapagos so close to Ecuador but with such different climates have animals so close to those of Ecuador but a little bit different the arguments about best digital structures why if whale bone whales were created perfect should their embryos develop and then resort before using teeth unless that shows that whale bone whales descended from ancestors with teeth all the classical evidences about evolution are imperfections that record history they must be i'll give you my favorite example which is the pandas thumb and that's why i chose that the title of a book there's everybody's favorite animal now the panda is a very peculiar member of the mammalian order carnivora that is its closest relatives among the mammals are the meat eating animals the cats the dogs the skunks weasels raccoons and particularly the bears to which pandas are most closely related but pandas belie the name of their order by sitting on their haunches all day and subsisting almost entirely on bamboo they do this by taking the bamboo shoots and passing each one between the fingers of the hand and what appears to be a thumb manipulating the bamboo shoot between the thumb and the fingers stripping off the leaves and eating the shoot is one doing it now when i first saw a panda in the washington zoo i said to myself wait a minute this makes no sense at all this just isn't right it confutes everything i ever learned because the primary lesson about the anatomy of carnivores that i remembered from my comparative anatomy one course is that all carnivores have lost the opposability of their thumb that is the anatomical first digit they have united that first digit with the other four to form a pad and that digits on that pad are capable only of backward and forward motion and that's fine for what most carnivores do that is for running and piercing and stabbing now once you make a complex evolutionary transformation of that sort and hook up all the muscles and nerves in a different way there's no easy pathway to go back to an opposable thumb now look at that that makes no sense if the pandas are truly descended from carnivores they should not have flexible opposable thumbs because of their prior evolutionary history and i was puzzled and then i look oh there's another one sorry i was puzzled until i counted the digits on the pandas poor you do it there are five of them and i said aha i'm right the anatomical first digit is not the a flexible opposable thumb of the panda it is united in the poor as it ought to be well if there are five digits in the poor and one of them is the true anatomical thumb what is the pandas thumb and what is the panda using to strip the bamboo i found out it is in fact using not a true anatomical digit at all but a detached wrist bone called the radial sesamoid we all have it it's the bone in your wrist nearest your thumb in pandas that bone is detached and it serves as a kind of thumb and the panda passes bamboo in between this false thumb or a large radial sesamoid and the digits of the hand here's the actual and there's the radial sesamoid thumb indicated by the red hand point the radial sesamoid thumb doesn't work very well it's not a jointed digit like the true thumb it's short it's clumsy the panda as it strips the bamboo looks like it has mittens on this is not an optimal solution yet given the pathways of history it is all that was available and evolution is opportunistic it uses available structures and it is constrained by a prior history of descent if god were into evolutionary if god created discrete species from scratch and were an optimal engineer he would not have built the panda this way now there's an even more important theme within adaptation and that is the importance of not i mean at least this is an adaptation it's an imperfect one but it works i want to talk for a moment about the importance of utterly non-adaptive structures structures that arise as architectural byproducts of other adaptations and although they may later be used in ways that we choose to call adaptations their origin is utterly non-adaptive and therefore we cannot see the world as an optimal one oh i forgot this one oh sure don't want to forget that this appeared in garfield garfield says i guess i'll have to hitch hike home fortunately for me i have something most other cats don't thumbs how true i hope uh jim davis had read my book maybe that's where he got it from i don't know it's the ceiling of king's college chapel in cambridge england and it represents the most complex form of ceiling vaulting that appeared in late gothic churches particularly in england and in the system of fan vaulting each the system of fan vaulting you get a fan emerging from each pillar it meets a fan coming from the pillar at the opposite end and as a necessary non-adaptive structural byproduct of the decision to build a fan vaulted ceiling you get and must get and every fan vaulted ceiling has this series of loson shaped holes right in the center of the ceiling i never was very tall and all the others up there every fan vaulted ceiling has them they're structural byproducts they're not adaptations now since they must be there you can use them secondarily in some adaptive way as happened here in the ceiling of king's college it was built by henry tutor and we have hanging from ceiling bosses the symbol of henry tutor's reign the rose and the portcullis on alternating bosses but it's a non-structural feature it's a secondary non is a secondary adaptive use i won five pounds last month from a hyper-adaptationist colleague who insisted that those ceiling bosses were structural we went up and walked on top of the chapel they are not indeed i knew that many other fan vaulted ceilings such as the retroquire of peter borough bath abbey that have the holes as all must but nothing in the holes now i use an architectural analog because i think this is a principle that's hard to understand when applied to organisms but i want to give what i consider the most striking example by way of a famous story from evolution to show how important this principle of non-adaptation is in some of the structures particularly the human mind that have been so vital in evolution and certainly in our own let me tell you a story about wallace and darwin they did not agree on everything in fact their greatest disagreement any chance of some lights their greatest disagreement occurred on the theme of adaptationism because wallace was a strict adaptationist wallace really did believe that natural selection had built essentially every little bit and piece of organisms for its immediate utility wallace was also one of the very few genuine non racists among 19th century science and he was therefore put into this dilemma which led him to argue that the brain could not have evolved by natural selection but it must have been made by god now the usual interpretation of wallace's view on the human brain is that he lacked darwin's courage that he was unable to carry forward the revolution that he could not apply it to the human mind that he lacked that kind of courage that may be a correct psychological explanation for all i know but in fact it's quite wrong when applied to the logic of wallace's argument which falls right out of his hyper adaptationist position wallace believed very strongly that the mental capacity of all human races was at least approximately equal in that he differed from the standard racism of most 19th century scientists but that also put him in a dilemma because although he was a non-racist he was a cultural chauvinist and he certainly believed that english society was vastly superior than what he called primitive or savage society and that put him in a dilemma if savage is his terminology had a brain every bit as good as ours but a culture so many of how many orders of magnitude ruder than ours how could the brain have evolved by natural selection because natural selection can only build things for use how could a savage have a brain as good as ours but not use it if natural selection built the brain therefore natural selection could not have built the brain now darwin's response was very interesting first of all he said i hope you have not murdered your child in my own secondly he answered with a very good response that's not part of this argument namely that savage so-called to size a lot more complex than you think mr wallace but his more interesting argument was as follows and i will put it in modern terms not in darwin's words namely yes undoubtedly the brain was built but we have a large brain because of natural selection i don't doubt that and natural selection work to give us a larger brain for some set of reasons probably very complex ones but that does not mean that everything the brain can do is a direct result of the operation of that natural selection the brain is a highly complex bit of computing machinery it may be built by natural selection to do a whole set of complex things but it can do many orders of magnitude more things as a structural consequence of the basic design of that computer itself i put a computer in my factory i may use it only to issue pagex and keep accounts but it can do by virtue of its structure any number of more things and that's how you have to look at the human brain most of what the human brain does i'm convinced is no direct result of the natural selection that built the large brain in the first part i just consider one fundamental fact that this large brain had allowed us to learn which has to be a fundamental constructor of human social institutions namely that most terrible fact of all that fact that no other animals clearly knows though maybe some do the fact of our own personal mortality the most frightening fact of all how much of of religion and divine right of kings how much of human institutions is a response of our learning about the fact of our personal mortality as a non-adaptive byproduct of having a brain large enough to give us the memory to recognize that we must see much of what the brain does not as the direct product of adaptation but as the complex set of byproducts and to that extent the world is not optimally perfect the world is a set of historically contingent accidents and so is human life and culture now darwin himself did not attack all four of the biases he was rather keen on gradualism himself i'll return to that in a moment and on the subject of determinism his own view was in an interesting halfway status natural selection is not a theory of random change it does incorporate randomness but not to produce change this is another aspect of natural selection theory that's widely misunderstood natural selection theory is a two-part theory randomness is called upon to produce the raw material to produce the variation upon which natural selection acts but evolutionary change is a result of natural selection working upon that random pool of raw material and selecting out the adaptive component thereof therefore darwinism is not a theory of random change and calls upon randomness only to produce raw material yet so great is our fear of randomness as an agent of change that many people reject darwinism based on this misunderstanding as how kestler says it all the time that darwinism is a theory of random change and therefore we have to reject it because the world is ordered well first of all you can produce a lot of order within random systems and second of all darwinism is not a theory of random change it calls upon randomness for raw material only however as i said darwin may have challenged two of the four biases but modern evolutionary theory challenges all four of them there are now and i've got to go through this quickly because this talk's getting long could be a whole other talk there are many trends in evolutionary theory at all levels that are calling upon randomness as a source of evolutionary change not replacing natural selection but expanding the range of evolutionary mechanisms that can account for transformation not merely for raw material at the level of genes the theory of neutral mutations argues that a large number of the genetic changes that occur in evolutionary lineages may occur without reference to morphological adaptation the level of species we're getting many theories arguing that the at least the initial step in speciation the fundamental initial step the attainment of reproductive isolation may be achieved not for reasons of adaptation but for reasons of larger often chromosomal changes that render a small group reproductively isolated from others now that group will not ultimately be successful unless it later develops subsidiary adaptations i don't mean that adaptation will play no role in the formation of new species but it may not be all that happens at the level of macro evolution or major patterns in the history of life we have again a set of challenges pointing out that random processes can produce much of the high degree of order that we see in the fossil record random systems do produce already if flip coins hundreds of times you have good predictions for what happens let me have the lights out again we have another series of slides this from some work i and some colleagues did about 10 years ago it looks like a very well ordered chart of the history of diversity of many lineages of fossils and if i started to spin out deterministic stories you would follow me and probably believe what i have to say i could tell you all sorts of tales look at roe b for example numbers seven and eight there's eight which evolved from seven and yet when seven became extinct at very high diversity eight continued to flourish for quite a time most evolutionists looking at that would say that the order of that pattern ipso facto suggests deterministic causes we must see in what morphological or behavioral features eight differs from seven look at their differences environment and then maybe we can understand why eight lived even though it was much less diverse than seven however this very ordered chart arises from a random simulation of the evolutionary process and we know in this case that nothing beyond the luck of the draw determined these patterns and yet many evolutionary patterns about which paleontologists have speculated in the causal mode for a century look very much like this there's another example and this is going to go by too quickly again the standard method for testing for random processes and this is a radioactive decay curve if you will as to plot the logarithm of the number of objects whether they're atoms or whatever against time if the random expectation holds in the case of radioactive decay meaning that each atom has an equal probability of decaying in each interval so it's like throwing dice then for reasons that i won't have time to explain but i just asked you to accept it the plot of the logarithm of numbers against time is a straight line that is the test for a random process you test for it by looking at straightness of line now here we don't have atoms we have numbers of surviving lineages the lines very straight and it better be because this is our random computer simulation and if it wasn't straight there'd be something wrong with the program the one thing no one would have expected in the history of life is that the extinction of species would be random it goes against all our suppositions that each species say each mammal has an equal probability of becoming extinct in each interval of time it doesn't sound right it ought to matter whether you're a lion or an anteater it ought to matter whether you lived 60 million years ago or 20 million years ago and yet lee van valen plotting radioactive decay curves for group after group of animals has claimed though there are others who disagree that in fact the history of the extinction of group after group looks like radioactive decay curves in other words the line is straight here's one that i did for reptiles and an impressively straight line despite the fact the history of reptiles is punctuated with mass extinctions so it may well be that randomness has an important role to play in evolutionary change as well and at several levels finally on the subject of gradualism my favorite one and easily a whole other lecture but which will be gone through in five minutes or less problem with gradualism and evolutionary theory has been that the fossil record red literally does not show it and all paleontologists know that and so to preserve gradual change one has to use the argument that darwin did perfectly good argument i just think extended too far namely that although the fossil record shows jerky patterns if we had all the missing strata you could fill in the continuities and there is the standard explanation based on the imperfection of the fossil record of why it is that the punctuated history of life really is gradual and so we get our illustrations in standard textbooks this is a standard american textbook on paleontology and it is not their illustration of gradualism it is purports to be their illustration of evolution the march of frequency distributions through time extrapolated to the whole history of life we have this pattern of stately unfolding with branches going ever upward and diverging at that constant acute angle of 25 degrees or so i don't think evolution looks very much like that i think it looks more like this this is the punctuated equilibrium pattern where species arise very rapidly in geological terms now that's thousands of years by the scale of our own lives a long time but if most species live for millions of years and tend not to change much during that interval if they arise in 10,000 though that's plenty of time for ordinary Darwinian processes it's still a fraction of one percent of their later existence and the geometry of life looks like this not like that ascending ladder of progress i don't have time to own the implications of punctuated equilibrium which i think are quite interesting particularly in the explanation of evolutionary trends but let me just say that you can no longer explain trends as the result of constant perfection perfecting by natural selection within lineages but trends must be recast as the differential success of species and that is a whole set implications there's an actual phylogeny of african pigs that i think displays the punctuated equilibrium pattern rather well just to show that gradualism is indeed a bias that still remains common in our culture here's a fortune cookie i picked up and what's inscribed on fortune cookies must be eternal verities of life this one says nature does not proceed by leaps the english translation of that famous maxim of Linnaeus not toro non-fuck it saltem i went out to walworth and bought one of those two dollar and eighty seven cent fake gold frames and that now sits on my desk the combined biases of gradualism and progress that great ladder-like approach to the history of life has given rise to all number of misinterpretations of evolutionary lineages let me just show you a few and this will be all for the slides here is marshes famous 1870 illustration of the evolution of the horse depicted literally as a ladder towards one toe and high crown teeth yet we have known though this continues to be commonly portrayed in the textbooks we've known for a century the history of horses shows no such thing but as a complexly labyrinthine branching bush of which the single surviving lineage happens to have that single toe and high crown teeth it is much more complex even than this i think the combined biases of progress and gradualism have been however most importantly constraining and misleading in standard interpretations of human evolution and i'll just show a few slides there here it's from henry fairfield osborne in the 1920s the supposed gradual evolution of the human brain from the chimpanzee to pithocanthropus or homo erectus to piled down and that's a funny one because piled down of course was a hoax constructed from a modern human cranium with modern human cranial capacity yet so great is the bias and the expectation of ladder-like progress that piled down even though it is a modern human skull when it was first reconstructed was reconstructed with an intermediate cranial capacity and then neanderthal whose brain if anything was actually a little larger than ours but shown smaller and finally us here's my favorite example these are the mcgregor busts of human evolution which used to adorn almost every anthropology department in the united states and it's a supposed evolutionary sequence that isn't from homo erectus on the left and neanderthal in the center to chromagnon on the right and the problem is it isn't an evolutionary sequence neanderthal is not an intermediate form neanderthal is probably us or something at least like us and it's very hard to portray it as intermediate when it isn't and doesn't even have an intermediate size brains so look what mcgregor has done under that bias of ladder-like gradualism he depicts neanderthal with a three-day growth and chromagnon is clean shaven to enhance the expectation now this is from a modern textbook the author of which certainly knows better but here is the march of human evolution literally in this case from dry epithecus or chimpanzees in the trees to austral epithecus shown stoop-shouldered even though we have known since the 1920s that austral epithecus walked as erect as uri up through neanderthal even neanderthal as shown is slightly stoop-shouldered even though mossland bool's famous stoop-shouldered reconstruction of the old man of lashepello synth was based on an arthritic specimen and that's been known for 30 or 40 years you see we still are constrained by these biases at least however the theme can be used for good humor as the next slide shows or or on a theme closer to the current issues that beset us the following that's all for the slide so if we could have the lights back on you won't have to turn them off again so in conclusion to this part remember i said that the second part but it's real short don't go in conclusion the best we can tell i think from modern evolutionary theory is that evolution is not a tale of ordained progress ladder-like leading towards us evolution does not produce an optimal world the world is not for the best it's full of imperfections that record that evolution itself there are elements of accident involved in change and not all is smooth and gradual and it's progressive tale in other words all four of pope's biases are fought by modern evolutionary explanations and that's true for human evolution too which brings me to this very rapid second part what specifically of us in our evolution i think the most curious thing of the history of attempts to explain human evolution is our general unwillingness to extend to ourselves the consequences that we're sometimes willing to accept for the rest of nature and there are two tendencies we use to try to preserve our hopes and biases at least for us the first strategy i like to call the strategy of the picket fence under that strategy you apply courageously to all of nature a set of naturalistic evolutionary explanations and then you make some special exception for us at the last minute that at least psychologically is what wallace did for the human brain so i talked about it before it's what charles lile did for example in arguing that the world was in steady state did not show progress but man and man alone was an imposition of the moral order progressively placed on earth at the end of time the second strategy quite opposite is called anthropocentrism and in that strategy what you do is you do put man in nature you don't try and establish the picket fence and make us separate you put man squarely into nature but in this crazy reversal of causality you see nature as existing for and directed towards us as though nature for four and a half billion years existed only to cough us up at the end of time and to produce this progressive product at the end the most powerful representation of that theme in the last 20 years is surely the movie 2001 with its finalistic account of human evolution in progress in terms of thinkers of this century surely the one who has become best known though whose ideas are not universally regarded as cogent my friend peter meadowar has been most dismissive of this particular individual teod to shod down i myself think he was involved in some funny other things that i'm not going to talk about but teod's philosophy of evolution was certainly strictly in this anthropocentric tradition i mean he did see all of evolution as occurring only to give rise to the union of matter and spirit in our own progressive growth uh his writing is incredibly dense by which many people think it's complex but it isn't i think you can display teod's basic beliefs as a set of fairly conventional mystical views in five or six statements first of all teod believed and i use this as an example of an anthropocentric system that evolution is the story of the increasing progressive domination of matter over spirit secondly early in the history of life while matter dominates lineages diverge though they're all moving in the same general upward direction but under the thrall of matter they diverge thirdly with man evolution has reached the halfway point consciousness has entered the universe and has actually spread over the earth in the form of a physical layer called the noosphere which started in africa where man evolved and is now although thin and tenuous spread over the entire earth fourthly although lineages under the thrall of matter did diverge continuously now that spirit has caught up the process of convergence shall begin and that convergence has already begun in the process of human socialization five as matter as spirit continues to dominate over matter lineages will converge more and more until they unite at a single point called point omega and identified with teod as god so the whole system has existed and life has caught forth its billions of species only so that of ultimately it could lead to this union of spirit with god and teod writes and his characteristic prose convergent movement will attain such intensity and such quality that mankind taken as a whole will be obliged to reflect upon itself at a single point to abandon its organo planetary foothold so as to pivot itself on the transcendent center of its increasing concentration this will be the end and the fulfillment of the spirit of the earth now i don't know what to do with a system like that i'll accept it as a poetic vision it's not science as i define science what can one say to such a scheme would it be too literal and mean spirited to argue that it seems to fail at its only points of testable contact with the fossil record few paleontologists can discern any general much less inevitable trend to increasing braininess in the history of life most animal species are insects mites copepods nematodes molests and their cousins and i at least can see no pervasive trend among them towards the domination of matter by spirit and the evolutionary tree does as i've said before look more to me like a complexly wandering and ramifying bush that tangled bank of darwin than a bundle of parallel twigs growing upward in a definite direction a point is schemes like the picket fence and anthropocentrism are motivated by hope just like the four biases but the world doesn't match our hopes and if i may reach some conclusion there is no simple answer they're eaten dare i don't if you're looking at how to interpret huxley's statement man's place in nature one can talk neither of the absolute separation of the picket fence nor the total immersion of the anthropocentric vision we have to look at some middle way human beings are special all species are special in some way in nature though we are special however we are the accidental result of an unplanned process and we may not see all of nature through us we are special but not a part the ways in which we are special have had profound consequences for the nature of our planet particularly through the agency of consciousness we have unleashed on the earth as peter meadowar once said so well a new process of cultural evolution which is lamarckian in form in which you do have a transmissal of acquired characters from one generation to another because what we learn we pass on to our offspring and a lamarckian system accelerates evolution at such an enormous pace that the attainment of this lamarckian style through human cultural evolution has caused a true rupture in the history of this earth secondly and i think the second great way in there in which we are special as a result of the unleashing of consciousness and cultural evolution the earth is changing due to our agency in an unprecedented rate just look out an airplane window nonetheless it's all an accident in that largest sense we are the fragile result of an enormous concatenation of improbabilities not the predictable product of any definite process let me just close by giving you one example of the concatenation of improbabilities as you know there was a great extinction 65 million years ago the dinosaurs that had dominated the earth at least the realms of large-bodied vertebrates for a hundred million years became extinct we've only had 65 million years since then there's no reason to think that if the dinosaurs hadn't become extinct that mammals and us would have evolved as we did mammals lived for a hundred million years most of the history of mammals is not the history of their success since the extinction of dinosaurs but is the history of a hundred million years as small creatures living in the interstices of a dinosaur's world had the dinosaurs continued i think mammals would still be small creatures living in the interstices of a dinosaur's world and triceratops might have been running around here rather than all you listening to us now what's the cause of the Cretaceous extinction who knows it's probably very complex but most of you are aware though within the last years a very serious theory that must be taken as a good contender that argues that at least a strong contributing cause to that Cretaceous extinction was the impact of some large extraterrestrial body upon the earth now suppose that's true and suppose that without it the dinosaurs might not have died and recovered what's more we only know of one lineage of primates a little form called purgatorious that lived before this potential asteroid hit suppose it had become extinct primates would not have evolved again many lineages of mammals did become extinct it's that set of improbabilities that greatest of all improbabilities the strike of a large extraterrestrial body may well have been the sine qua non of our existence and there are hundreds of other historically contingent improbabilities involved in human evolution now finally lest you think i'm trying to give you a pessimistic message i don't see it that way i view everything i'm saying optimistically maybe it's just the way i look at it you see yes indeed i'm saying there are no answers in nature directly to our hopes and to our moral dilemmas but i think that's fine i don't think you're supposed to look to the facts of nature to the answers for the answers to moral dilemmas i think that's the job of human intellect to construct for itself that's the job of the humanistic scholars it's the job of all of us as human beings not the job of scientists to find it in nature and i think that's a wonderfully optimistic message that leads us on to the search let me close then just with Linnaeus' own solution to this dilemma of the middle way that we're both in nature but apart from nature because he had the most wonderful way of expressing it and i'd like to close with that when Linnaeus in 1758 made the first formal classification of animals that remains the basis of our system today he put man directly into nature by classifying us and that was not always traditionally done with other mammals in fact he constructed a group of three the genus homo for us the genus simia for monkeys and the genus bradipus for the sloth and its allies so he put us firmly into nature and yet in an interesting way he also displayed the differences because when he came to describe the different genera for all the other genera for monkeys and for sloths and for all the others he gave morphological features and i hold here his definition of the genus simia dentis primores quadro approximates tell you about the form of the teeth and the form of the hair but then when he gets to this genus homo he doesn't do that he writes only one thing he writes homo no se te ipsum know thyself thank you ladies and gentlemen since we're to be back here at 3 30 we'll we'll go to the question period after the next session and the president says we'll take a break for coffee and cookies on the mall