- 2 years ago
What do dinosaurs, a panda's thumb and a peacock's tail have in common? Dr. Stephen Jay Gould, the internationally renowned paleontologist and Evolutionary theorist, provides some surprising answers in this NOVA profile.
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00:00Oh, beauty. You're a good pitcher, Nancy.
00:24Be an announcer.
00:27I guess everyone has certain people who play key roles in their own lives.
00:32Strike three.
00:33For me, I think I'd single out my father, although he didn't have a whole lot of formal education in his own background,
00:39and always wanted me to have an intellectual life.
00:44Secondly, Joe DiMaggio, the hero of my youth, taught me the thing that counts is excellence.
00:52And thirdly, when I got a little older, Charles Darwin.
00:56Stephen Jay Gould, baseball fan and evolutionary biologist, is one of the liveliest voices in science today.
01:04A keen-eyed observer of nature, Gould writes award-winning essays on subjects from mass extinction of dinosaurs to land snails of the Bahamas.
01:14Here at Harvard University in Cambridge, Massachusetts, Gould is professor of paleontology.
01:20He teaches a popular course with the ambitious title, The History of the Earth and of Life.
01:26His humor and enthusiasm draw large crowds wherever he speaks around the world.
01:31He seems to have an extraordinary talent for making science both exciting and accessible.
01:38In this film, we will explore the wide world of Stephen Jay Gould's ideas,
01:44from human origins in South Africa, to the biological basis for human equality, to the future of all life on Earth.
01:57Our standard view of the history of life is more based on our hopes and expectations and the realities of nature.
02:04We try so hard to see nature as a progressive process leading in a predictable and determined way towards us,
02:12the pinnacle of the creation or the evolved world.
02:17But a closer examination of nature, based on a conscious attempt to identify and eliminate those biases,
02:23I think shows us that it's nothing of the sort.
02:26History is quirky, full of random events.
02:29There's no vector of progress that can be discerned in it.
02:33I don't find that at all depressing. I don't think we're supposed to find moral messages in nature.
02:37I think we're supposed to construct them ourselves.
02:39Nature is as we find it, fascinating as could be.
02:47Gould's passion for paleontology began nearly 40 years ago,
02:51with a visit to the American Museum of Natural History in New York City.
02:57When I was a little kid, I was just fascinated by dinosaurs.
03:01But when I was 10 or 11, I discovered there was a wonderful set of exciting ideas
03:07that lay behind our understanding of those wonderful and exciting bones, namely evolutionary theory.
03:13Evolutionary theory always intrigued me, I guess because it's, as I like to say, the roots phenomenon writ large.
03:20We seem to all be interested in our origins, at least on the small scale of our own family histories,
03:26but evolution is family history writ large.
03:29It is the connections among life.
03:31It explains, insofar as science can deal with the issue at all, why we're here, how we got here,
03:36what our relationship is with the rest of living things in our world.
03:42That's why evolution is one of the half-dozen great ideas that science has ever developed.
03:48If you make a survey of paleontologists, you'll find that a majority of them were country people
03:53who had access to fossils as children.
03:56But there's a small subset of city street kids, like myself, who got intrigued about paleontology
04:02because they saw dinosaurs in museums.
04:04And in fact, it's this very specimen that at age 5 made me decide on a career.
04:10My father brought me here when I was 5, and I stood under this very specimen.
04:15A man sneezed, and I sure thought that was the end.
04:18But I recovered, and after an hour looking at these weird, wonderful creatures,
04:22I decided to devote my life to them.
04:24Now, that's not rare.
04:25Millions of kids want to be paleontologists.
04:27What's rare is to stick with it, and I'm one of the few who did.
04:33It's the first day of the fall term at Harvard University,
04:36and more than 800 students stand in line to sign up for this introductory course in the history of Earth and life.
04:43Stephen Jay Gould is one of Harvard's most popular professors,
04:47and there's only space in the course for 300.
04:49So many students will have to wait and try again next year.
04:54Science is a fascinating dialectic.
04:56It creates culture by instigating change through its discoveries,
05:01but it also reflects culture because it's done by human beings
05:04who are enmeshed in the biases and thoughts of their age.
05:07They're no different from anybody else.
05:09Scientists aren't special.
05:11That's one of the main themes of this course.
05:13Science leads and provokes change, but science is also embedded in culture
05:17and often reflects the largely unconscious biases of those who do the work.
05:23Gould challenges his students to rethink popular biases about nature and the way the world works.
05:29Now, there's four biases.
05:32First of all, the notion of progress.
05:36I think we'd all say now,
05:38oh, no, we don't believe in progress.
05:39We know that life wasn't ordained to give rise to humans at the end.
05:43But deep down inside, the bias of progress motivates that thinking
05:47about so many things so deeply that we hardly recognize it.
05:51And we still, in so many ways, see the world as moving somewhere,
05:55and because we got there late, in some sense, it's moving towards us.
05:58It's the basic notion that gives us right to dominate.
06:02So that's the first bias, the bias of progress.
06:04We'll be discussing that a whole lot.
06:06And even if you explicitly claim you don't believe it,
06:08I think I will show you many theories you do believe
06:11that are based on little more than a concept of progress
06:14that you may never have recognized supports the idea itself.
06:18The second, and in many ways equally important, is the bias of determinism.
06:26Simply the idea that things have causes, that we live in an ordered world,
06:30that any event that seems to be patterned
06:32is produced by some definite cause operating for that result,
06:36and that randomness is something frightening and rare
06:38and that doesn't produce pattern anyway,
06:40and if it exists, it's only responsible for chaos.
06:43The third great bias is gradualism, my personal favorite,
06:49namely the notion that change is intrinsic to the universe,
06:52but it comes about through slow, steady, stately, progressive steps.
06:57I hope you see how all this goes together.
06:59All these biases go together to reinforce a comforting view of human life as...
07:07Well, let me give you the fourth one, and then see what I mean.
07:10The fourth is adaptationism,
07:13by which I don't narrowly mean Darwin's theory of natural selection.
07:17I mean the broader view that everything fits,
07:20that it's here for a reason, that everything works,
07:23that the relationships in ecology, the form of organisms, is somehow right.
07:30Now, I think you can see how all these go together.
07:32If there isn't here in progress and if things happen for a reason
07:35and develop in a slow, steady, and stately, progressive way,
07:39and eventually lead to a system where everything fits,
07:42then it all works out.
07:43The world is logical, the world is rational, the world is well-ordered,
07:46it's there for a reason, we dominate it.
07:49We dominate by right, by evolution, by progress, by determinism.
07:52All these ideas go together.
07:55Once we realize that the aspects of the world that we just take to be unquestioned truth
08:00are often constrained by cultural and historical bias and expectation,
08:04that they aren't just facts of nature,
08:06but in fact reflections of our deepest hopes and cultural situations,
08:11then we can understand them, we can get rid of them,
08:13we can consider alternative viewpoints.
08:15Alternatives that we've never even regarded as possible before.
08:20Until the last century, religious and scientific notions of life
08:24rested on a belief in changeless, ideal forms.
08:28The world had been divinely created in six days,
08:31and each creature had its fixed place in the universe.
08:35Its form could not alter.
08:38In 1831, Charles Darwin, an amateur English naturalist,
08:42embarked on a five-year voyage around the world.
08:45Stopping at the remote Galapagos Islands off Ecuador,
08:48Darwin observed a large variety of reptiles and birds.
08:53He noted that each individual island he visited
08:55had its own distinct forms of mockingbirds and tortoises.
09:00He later realized that, separated by ocean barriers,
09:03island populations varied independently, allowing new forms to arise.
09:08In 1859, he published The Origin of Species.
09:12His theory of evolution argued that all species are related
09:16by descent from a common ancestor.
09:19English society was scandalized.
09:22For two decades, Darwin was scorned for suggesting
09:25that noble humanity bore kinship with the lowly ape.
09:32But by the time of his death in 1882,
09:35Darwin's theory of evolution had obtained wide acceptance.
09:41Darwin will always be remembered as one of the greatest thinkers
09:45in the history of humanity,
09:49mainly because he was such a brilliant man and such a splendid human being.
09:53But more specifically, he did, after all, more than any other human,
09:58establish the fact of evolution,
10:00which is one of the great concepts that science has discovered
10:05and that has endless implications for our whole concept of ourselves
10:09and the nature of life.
10:11He also developed the theory of natural selection,
10:14which, a hundred years later, remains very strong
10:18and I'm convinced will be the centerpiece of any future,
10:22more adequate evolutionary theory.
10:25Natural selection involves no master plan by nature.
10:29As environments grew colder in the Pleistocene,
10:32mammoths with heavier coats of hair fared better,
10:35and so did their descendants who inherited their genes.
10:38Random genetic variation provides the raw material for natural selection.
10:43When the Ice Age receded,
10:45long hair ceased to be an adaptive benefit,
10:48and woolly mammoths disappeared.
10:50Natural selection is based on the idea
10:53that organisms produce more offspring than can possibly survive.
10:57The ones that do survive are those that inherit genetic variations
11:01favorable for the environment where they live.
11:04Survival of the fittest.
11:06Natural selection not only executes the unfit,
11:09it also creates the fit by preserving the best adapted.
11:14This light-colored pantheon moth was perfectly camouflaged
11:18to match lichens growing on tree trunks
11:20and thus avoided the sharp eye of predators.
11:23But in recent years, the environment has been changing.
11:26Soot from industrial pollution has descended on the countryside,
11:30slightly darkening the surface of many trees.
11:34Before 1940, collections of pantheas contained only pale ones.
11:39But after 1940, natural selection favored a dark mutant variety.
11:45Soon, North America had areas where they comprised 80% of the population.
11:51These dark moths and their offspring thrived,
11:55while pale moths, which lacked the adaptation, were without protection.
12:01The blue jay acts as the agent of natural selection,
12:08while the dark moth makes a clean getaway.
12:15The great illustrations of natural selection are exquisite local adaptations,
12:20not progressive stages.
12:22Every naturalist has their favorite example.
12:25Mine concerns a clam named Lamsillus.
12:28It's a freshwater mussel,
12:30and it builds on its rear end a virtually perfect decoy of a fish.
12:36It has eye spots, it has fins, it has a tail, it moves them like a fish.
12:41And you ask, why would a clam build a fish on its rear end?
12:44It doesn't seem to make any sense
12:45until you consider the natural history of this particular clam.
12:49It's a member of a group that uniquely among clams has larvae
12:53that must become parasitic on the gills of fish for a time in order to grow up.
12:58So, this decoy fish literally attracts others.
13:03True fish, that is.
13:04They come swimming down into its area.
13:07But since the fish is really a brood pouch that holds the larvae of the clams,
13:11as soon as a fish comes by to investigate,
13:14the mother shoots the larvae out of the fish,
13:17some of which attach to the gills and begin their free ride into the next generation.
13:22So, in no sense can you say that Lamsilis is a better clam.
13:26It's not a progressive stage in clamness.
13:30It's not better than a scallop. It's not better than a quahog.
13:33It's just one creature that has evolved a very curious, exquisite design
13:38as a direct response to a peculiarity of its own lifestyle.
13:43But exquisite design is not always the rule in nature.
13:47The panda has evolved a very clumsy contraption to assist in the eating of bamboo.
13:52One of the main misunderstandings that I think many people have about evolution,
13:57particularly about Darwinism, is the idea that if you want to prove evolution
14:01or give the best evidence for it, that you look for those beauties of design,
14:06the bird's wing with its aerodynamic perfection.
14:08And that's quite wrong.
14:09And Darwin understood that it was wrong
14:11because perfection, though it can be built by natural selection,
14:14covers the tracks of history.
14:16The evidence of evolution lies in imperfections
14:18that record historical pathways of descent.
14:21My favorite example is the panda's thumb,
14:24which isn't a thumb at all. It's an interesting story.
14:27Pandas, by evolutionary descent, are carnivores.
14:30That is, they're descended from meat-eating animals.
14:33But pandas, by more recent evolutionary history and adaptation, become herbivores.
14:39They, in fact, spend almost all their waking hours sitting on their haunches eating bamboo.
14:44And they do that by taking each bamboo stalk
14:47and stripping the leaves off by passing the stalk
14:50between what appears to be a flexible thumb
14:52and the rest of their paw and eating the young shoots.
14:55Now, when I first looked at that in the Washington Zoo,
14:57I said, this doesn't make any sense.
14:59The first thing I ever learned about the anatomy of carnivores
15:02is that they've lost the opposability of the thumb.
15:04Carnivores don't use thumbs for that kind of motion.
15:08The thumb of all carnivores is united with the other digits.
15:11The muscles and nerves are changed in many complex ways to accomplish that.
15:15It looks like the other digits.
15:17It's just capable of backwards and forwards motion,
15:20which is what carnivores have to do because they run and they stab and scratch.
15:24They don't need an opposable thumb, and they've lost it.
15:27So I looked at this panda, and I said, how could this be?
15:29It doesn't make any sense.
15:30And then I found out, of course, well known,
15:32the answer is it's not a thumb at all.
15:35The panda, in fact, has used the radial sesamoid bone of the wrist,
15:40this little bone here.
15:41It's become detached from the rest of the wrist.
15:44It's elongated, and that's the so-called thumb of the panda.
15:47It's not a true thumb at all.
15:49It's the radial sesamoid bone enlarged.
15:51The interesting thing about that is the radial sesamoid thumb doesn't work very well.
15:54It's very clumsy.
15:55The panda looks like it's wearing mittens.
15:57It can't work very well.
15:58The radial sesamoid bone is a small bone.
16:00It's not jointed like the true thumb.
16:02It can't establish those nerve and muscle connections that make for fine motion.
16:06It's a very clumsy thumb.
16:08If God had created the panda from scratch to eat bamboo,
16:11he wouldn't have made it that way.
16:12The panda is built that way because that's all that was available
16:15due to the previous evolutionary history as a carnivorous animal.
16:18And it's in that way that imperfections are the great evidence that we have for evolution
16:23because they record the paths of history.
16:25For the past 15 years,
16:27Steve Gould and his partner David Woodruff
16:30have been studying a land snail of the Bahamas called Sirion,
16:34which spends most of its life hanging upside down on trees.
16:37Unlike most organisms,
16:39snails preserve an entire record of their growth in the whorls of their shell.
16:44A species is a group of organisms that become so different from others
16:49that it can't interbreed with them.
16:51Because Sirion shows great variety in form,
16:54scientists used to think there were more than 600 different species of the snail.
16:58But Gould and Woodruff's research shows there are in fact fewer than a dozen.
17:03Sirion is probably the most diverse land snail in the world in terms of form.
17:09And my main interest is the evolution of form.
17:11So it's best to choose an animal that is remarkable in its diversity.
17:17And they range from this square snail,
17:20which one friend of mine once said was an impossibility among animals,
17:23to this dwarf, pencil-shaped creature,
17:26to this giant, which happens to be the largest Sirion known.
17:30I even found it.
17:31To this curious, corrugated white form,
17:34to this mottled, smooth form.
17:36And that's just some of the diversity.
17:37In fact, I'm trying to understand why it is
17:39that a single, fairly common genetic system
17:42can develop such enormous morphological diversity.
17:44If I can solve that problem,
17:46then I've learned something fundamental about the evolution of form.
17:50Namely, how is it that big changes, or apparently big changes,
17:54are produced by small inputs that have large effects?
17:59Gould's study shows that the same complex forms of Sirion
18:03evolve again and again on separate islands.
18:06Although the mechanisms are not yet understood,
18:09Gould is beginning to think that Sirion's development
18:12may be controlled by master genetic switches.
18:15These switches may channel the snail's development,
18:19enabling the same traits to arise many times over.
18:25It's the single greatest joy of my intellectual life
18:28to know with intimacy the details of a part of nature.
18:33Even a tiny little part is almost unexpressible
18:37in the pleasure it gives.
18:39I freely admit there may be only half a dozen other people in the world
18:44who care about this particular animal the way I do.
18:47But the other reason is purely personal.
18:49There is a joy of discovery.
18:52Finding something new, it's the most unsullied,
18:55most precious kind of intellectual achievement, even if it's small.
18:59I mean, to say I found this, nobody's seen it before.
19:02It's really new, even if small. But I found it.
19:06The fossil record is the telescope which paleontologists use
19:10to look far back into evolutionary history.
19:13Darwin believed that organisms evolved slowly and gradually
19:17as they adapted to changes in their environments.
19:20And so, one might expect to find these transitional creatures
19:23recorded as fossils.
19:25But transitional forms were seldom found.
19:28It seemed as if paleontologists had been condemned to study
19:32that which they could not see.
19:34But in 1972, Gould and his colleague Niles Eldridge
19:38introduced a new theory called punctuated equilibrium,
19:42which challenged the idea that most change is gradual.
19:47They argued that new species like these fossil mollusks from Kenya
19:51arise abruptly, almost instantly in terms of geological time,
19:55and then settle down into a long period of stability.
19:59Transitions between species are rarely found
20:02because change occurs so rapidly.
20:05Gould and Eldridge's message was,
20:07use the fossil record as valid evidence.
20:10Change may often be sudden,
20:12and stability constitutes much of life's history.
20:17The issue at stake is the very nature of change itself.
20:21There is, I think, a pervasive bias in Western thought
20:25to see change as slow, steady, accumulative, gradual,
20:30to see change as the essence of nature.
20:33There's another view, however,
20:35that stability and system and structure is more of the essence,
20:39and that change, when it occurs, is difficult,
20:41that systems absorb stress and try to maintain themselves,
20:47and that every once in a while,
20:49the stress accumulates to a point where the system breaks
20:52and quickly reconstitutes in a new way,
20:55so that change is not always continuously accumulating,
21:00but is rare and episodic,
21:02and that systems tend to sit at stable points as much as they can.
21:07It's a different way of viewing the world.
21:09My colleague, a British geologist, Derek Ager,
21:12once said it was like that famous quip about the life of a soldier,
21:17and that it consists of long periods of boredom
21:20and short moments of terror.
21:24That same description has also been applied to the game of baseball.
21:28Steve Gould often draws parallels
21:30between the history of life and his favorite game.
21:34Nova arranged a visit for 11-year-old Ethan Gould and his father
21:38with one of baseball's all-time great players,
21:41New York Yankee star Joe DiMaggio.
21:46Keep your eye on the ball all the time.
21:48When you're taking your nice, normal swing,
21:50you're always right there, your head stays right there,
21:52your eyes are on that ball all the time, and follow through.
21:55Where's your uniform? I understand you've got a uniform here.
21:57Well, I just wore the top of it.
21:59Well, that's the Reds' uniform.
22:01Joe DiMaggio was amazing grace on the ball field.
22:04I never saw anybody, never have since, play as he did.
22:08Hit, field, catch, do everything, make it look easy.
22:12With such poetry and grace,
22:15I think I could see in him, even as a young child,
22:18that personification of excellence.
22:23My real secret love would have been to be center fielder
22:25for the New York Yankees. I was waiting for you to retire.
22:27And then they got Mickey Mantle, and I never had a chance.
22:30It was the greatest moment of my life.
22:33One day, I think it was 1949 or 1950,
22:36as I remember, it was a doubleheader with the St. Louis Browns,
22:38and the Yankees lost both of them. Maybe it was just a single game.
22:41You pop one off, and I said, Dad, catch it, catch it!
22:44He stuck his hand up just like that, and the ball fell into it.
22:47So I took it home, and I washed it several times,
22:49which is why it doesn't say official American League ball anymore.
22:52And then they sent it to you and asked you,
22:54would you sign it and send it back?
22:56I don't know that I ever expected to see it.
22:58Years later, I was playing ball behind the house,
23:00and my brother comes running out, and he says,
23:02look, a ball from Joe DiMaggio came back.
23:04And there it was. I mean, you sent this back,
23:06and I remember it even said insured.
23:08I was very impressed.
23:10I don't know, all my childhood, I would keep telling my friends
23:12over there in Queens, you know, I got this ball signed by Joe DiMaggio.
23:15And they'd say, aw, come on, Gould.
23:17It was like having a ball signed by God.
23:19And then I'd bring him to the house, and I'd show him this thing,
23:21and they'd look at it in awe.
23:23So basically, I just wanted to thank you, because I was...
23:25And that definitely is my signature.
23:27Oh, yeah, I know.
23:29That's the way I signed during that period of time.
23:31I was just a nothing 9-year-old kid,
23:33and you didn't have to send it back.
23:35You must have got 100,000 of them every day.
23:37But you did, and I just wanted you to know
23:39how much it meant to a kid growing up.
23:45The great records of the early days,
23:47Joe DiMaggio's 56-game hitting streak in 1941,
23:51and Rogers Hornsby's .424 batting average in 1924
23:55are not being equaled today.
23:57Where have all the great ones gone?
24:00I think you have to look at the disappearance of 400 hitting
24:03as a response of systems to their history,
24:07and not as some failure of resolve among the greats.
24:11It's systems that change, not individuals.
24:15And when you take that approach,
24:17you realize that the mean batting average
24:19has not changed since 1900.
24:21It sits around 260.
24:23That's what it was in 1900.
24:25That's about what it is now.
24:27What's happened is you had a decrease of variation
24:29around that constant average.
24:31Now, you almost hit 400,
24:33and hit 381 one year,
24:35and I gather you were above 400
24:37until the end of that season.
24:39I was, up until two weeks of the season.
24:41We had the pennant cinched.
24:43There was nowhere to go.
24:45We had it all wrapped up,
24:47for individual honors.
24:49And it so happened that I caught a cold in my left eye,
24:51which is the late eye,
24:53and I had to watch the pitcher throw from that side.
24:55I got myself into a sump,
24:57and I lost 32 points.
24:59And you were above 410?
25:01Yeah, I was 412.
25:03412, two weeks to go.
25:05That's right.
25:07I don't think that there were giants in the earth
25:09in those days, and people don't try hard now.
25:11I think the great players of today
25:13are as good as they were then.
25:15Baseball has become so automatic,
25:17so regular,
25:19so beautifully coordinated a system.
25:21The advantage that great players could take
25:23of a looser and less well-organized
25:25and less regulated system
25:27has disappeared.
25:29The extremes move in towards the average.
25:31History of life has proceeded
25:33in much the same way.
25:35If you look back 500 million years ago,
25:37the early history of invertebrates,
25:39there was an enormous range of designs
25:41which we see no longer on the earth.
25:43Designs that we don't even know
25:45how to relate to any existing group.
25:47If there's any pattern in the history of life,
25:49it's not progressive advancement
25:51of complexity.
25:53It's rather the restriction
25:55of these enormously varied designs
25:57that existed early in the history of life
25:59to a few highly successful forms.
26:01Genes as well as organisms
26:03may be the targets
26:05of natural selection,
26:07as they carry on their own reproductive struggle.
26:09In fact, Gould believes
26:11that natural selection takes place
26:13at a number of separate levels.
26:15Genes, organisms, and species as well.
26:17Individual organisms
26:19may develop adaptations
26:21which help their reproductive struggle,
26:23but which may ultimately threaten
26:25the future of the species.
26:27According to Gould,
26:29there may often be such conflicts
26:31between separate levels of evolution.
26:33Take the classic case of the peacock
26:35with its enormous tail feathers.
26:37That's good for the organism.
26:39Their tail wins more copulations
26:41and leaves more offspring,
26:43and that's good at the traditional Darwinian level
26:45of struggle among individuals.
26:47And yet in designing such a complex
26:49and otherwise not functional structure,
26:51the peacock, in a sense,
26:53is sealing its own doom
26:55as a species.
26:57Good for the organism,
26:59bad for the species.
27:01If the environment were to change radically,
27:03peacocks would soon face extinction.
27:05Such was the fate of the great Irish deer,
27:07which grew a rack of antlers
27:0912 feet long
27:11and enjoyed great reproductive success.
27:13But such a highly specialized creature
27:15could not survive the rapid changes
27:17of the late Ice Age environment.
27:19It's most likely
27:21that extinction is the ultimate fate
27:23of all species.
27:25Gould does not regard this thought as tragic
27:27and suggests that human values
27:29should not be applied to nature.
27:31One of the more amusing misuses
27:33of nature that pervades
27:35the history of Western thought on this subject
27:37is our endless attempt to find
27:39moral meaning in nature,
27:41to find the exemplification of
27:43principles of right conduct and living.
27:45And it just doesn't work.
27:47Nature is neither kind nor cruel.
27:49It simply is as we find it,
27:51and it's full of phenomena
27:53that are repulsive to us
27:55or joyful to us.
27:57And it must be so
27:59because there are no inherent moral messages.
28:01My favorite example
28:03is the story of the so-called ignomonid wasps.
28:05This is in fact a large group of wasps
28:07who paralyze prey,
28:09usually caterpillars,
28:11and lay their eggs directly in the body
28:13of the caterpillars who are still alive,
28:15though paralyzed, the younger born,
28:17then eat up the caterpillar from inside,
28:19but very carefully,
28:21making sure that they save the heart and nervous system
28:23for last, because they don't want to kill the caterpillar
28:25lest it rot and destroy their source of food.
28:27Now there's one of the most horrible
28:29events with respect to
28:31moral hopes, but nature doesn't care.
28:33It's merely an adaptation that's good for wasps
28:35that caterpillars haven't been able
28:37to overcome. And yet, if you look at the
28:39history of comment upon this, throughout the
28:4119th century, various
28:43rectors and interpreters
28:45of nature, for our benefit,
28:47tried to find moral wisdom.
28:49They argued, for example,
28:51that we had here an excellent case
28:53of mother love. Look at the
28:55wasp caring for its
28:57progeny. Or,
28:59the argument might have been that we have to get rid
29:01of caterpillars anyway, because they're such a scourge
29:03on human crops, and it doesn't matter what
29:05mechanism nature uses.
29:07Or, people looked
29:09at the care and husbandry
29:11of the little larvae as they
29:13kept the heart and nervous system for last
29:15as a good example of the use of
29:17resources in intelligent ways,
29:19and saw that as a proper model
29:21for human agriculture and exploitation.
29:23But it just doesn't make any sense.
29:25The point is there are no moral messages in nature.
29:27Darwin understood that
29:29perfectly well, and, in fact, used the
29:31enigmatic wasp as a primary example of why
29:33you couldn't find them.
29:35And that's appropriate. I don't think
29:37science contains
29:39the answer to moral questions. Moral questions
29:41have to do with the way in which we ought to live
29:43our lives. Science can only tell us about
29:45the way in which the world is
29:47constructed. Now, some people think that's depressing,
29:49and therefore think that Darwinism
29:51is a terrible
29:53system that we have to
29:55expunge from our schools and erase
29:57from our thoughts. But to me, it's
29:59exhilarating and challenging. I don't want to
30:01passively read the answer
30:03to great moral dilemmas in nature.
30:05I want that to be an active challenge
30:07to the humanistic side
30:09of our minds. Moral answers
30:11are something we have to construct from the depths
30:13of our own lives. We don't read them passively
30:15in nature. They're not there.
30:17Darwin's metaphor for life
30:19was a branching bush in which each
30:21twig is connected to its ancestors.
30:23A new species does not
30:25replace another. It splits off
30:27to form its own branch.
30:29Each local branch, once separate,
30:31remains separate forever.
30:33There's no going back in evolution.
30:35This metaphor
30:37challenged an older view of
30:39life as a ladder of progress,
30:41with amoebas and insects at the bottom,
30:43monkeys and apes in the middle,
30:45and humans at the pinnacle
30:47of complexity and importance.
30:49The branching bush
30:51is neutral, conferring no special
30:53status to any creature.
30:55This ordering of life is not
30:57in any way, to me,
30:59depressing or
31:01pessimistic, unless
31:03you feel that to justify your
31:05own status on earth you must view
31:07yourself as the end
31:09of a ladder-like process moving
31:11towards you right from the start.
31:13I'm quite happy to conceive
31:15myself as merely one twig
31:17connected to the rest of life
31:19through the bush of evolution,
31:21as just one little
31:23struggling species like
31:25all others enmeshed in nature
31:27and trying as best we
31:29can to be part of it and to survive
31:31as long as we can.
31:33The history of human
31:35ancestors begins with Australopithecus
31:37nearly four million years ago
31:39and tells its own tale of frequent
31:41branching. Africanus
31:43and Robustus lived less than a million
31:45years each, then died out.
31:47They had brains half the size
31:49of ours. The brain size of our
31:51own species, Homo sapiens,
31:53has not changed in the past
31:5530,000 years. Our
31:57biological evolution may be
31:59over. In the 19th
32:01century, it was common practice to
32:03rank human races and their
32:05evolutionary relatives on a ladder
32:07of progress, with the chimpanzee
32:09at the bottom, a black man in the
32:11middle, and a classical white
32:13male on top.
32:15In one nation today, this
32:17old idea is still official doctrine.
32:19The
32:21Makapansket Valley of South Africa
32:23is surrounded by a cluster of hills,
32:25which have yielded fossils of some of the
32:27earliest hominids known.
32:29Last summer, Steve Gould
32:31traveled to South Africa
32:33to give a series of lectures on the history
32:35of scientific views on race.
32:37He visited this site with a group
32:39of students from Johannesburg.
32:41Here, in 1946,
32:43the skull of an Australopithecine
32:45was found in the debris heap of
32:47an old limestone quarry.
32:51Scientists conduct
32:53fieldwork here to look for further
32:55specimens, and to try to learn about
32:57the kind of life Australopithecines may
32:59have lived in this valley 3 million
33:01years ago.
33:03Much
33:05evidence may have been destroyed at the turn
33:07of the century. The owner of
33:09the quarry at that time was a staunch
33:11creationist who strongly rejected
33:13the theory of evolution.
33:15He ordered that all fossils found
33:17by his miners be burned
33:19in the quarry's lime kiln to destroy
33:21any evidence of evolution.
33:25Large quantities of bone
33:27are embedded in the cliff walls.
33:29Stones and bones
33:31are studied for surface wear to
33:33determine whether they were ever used as primitive
33:35tools.
33:37Gould's trip
33:39to South Africa was financed
33:41by a group of students at the University
33:43of the Witwatersrand in Johannesburg.
33:45This university
33:47is one of the few liberal institutions
33:49in South Africa which permit
33:51black students to study alongside
33:53whites. Gould
33:55lectured here on human evolution
33:57and on the biological basis
33:59of human equality.
34:01I got a lot of letters from American
34:03creationists, and one of their favorite arguments,
34:05which really shows that misunderstanding,
34:07is they really think they have you say,
34:09okay, you're an evolutionist, but I really got you.
34:11You say we evolved from apes, right?
34:13And I say, yeah, we evolved from apes,
34:15that's right. Okay, if we evolved from apes,
34:17why are apes still around?
34:19Answer that one for me.
34:21I just have to laugh because,
34:23of course if it were true that evolution was a ladder of
34:25progress and we evolved from apes, then there are apes,
34:27and then there are us. But evolution isn't a ladder
34:29of progress, it's a branching bush.
34:31When one branch branches off and becomes
34:33something else, the other guys don't disappear.
34:35We branch off from apes and apes continue.
34:37Well, it's the same thing in human evolution.
34:39We branched off. I mean, somewhere
34:41from the Australopithecine stock, the genus
34:43Homo, branched off.
34:45But Australopithecus might have survived.
34:47It didn't. Indeed, the robust line
34:49of Australopithecus survived until probably
34:51somewhat less than a million years
34:53ago. It might have survived. It was contemporaneous
34:55with Erectus. We don't know why it
34:57died out. Might have survived another million
34:59years. Now suppose it had.
35:01Then equality would
35:03not have been a contingent fact of history.
35:05Then we would have been saddled
35:07with the moral dilemma of a truly
35:09inferior human species
35:11with half our cranial capacity. I don't
35:13know what we would have done. Zoos?
35:15Servants? Concentration
35:17camps? I don't know, but human history would
35:19have been different. And that's what I mean.
35:21Human equality is a contingent fact of history.
35:23It could have been otherwise. It might very
35:25well have been otherwise. It just wasn't.
35:27That's the point.
35:34The affluence of the city
35:36of Johannesburg stands in harsh
35:38contrast to the poverty in which
35:40many black South Africans live
35:42under the doctrine of apartheid.
35:44Blacks outnumber whites
35:46here nearly four to one,
35:48but they do not have the right to vote.
35:52Though many blacks work in cities,
35:54they must live in segregated
35:56townships or homelands,
35:58often separated from their families.
36:00The African
36:02continent has proved to be the
36:04cradle of human evolution.
36:06All the earliest fossils have been found
36:08here. Still, many
36:10expeditions have been launched in the hope
36:12of finding our ancestors in Europe
36:14or in Asia.
36:16We come then to the geographic argument,
36:18which is the denial of Africa
36:20as the homeland of
36:22humanity, as we now know it is.
36:24Because there has been
36:26this long wish in the racist tradition
36:28to see the African peoples
36:30as secondary and degenerate,
36:32and not to see African
36:34native peoples of Africa
36:36as representatives of the actual homeland of humanity.
36:38Now Darwin, I might say, made the
36:40correct prediction from a very simple argument.
36:42Darwin himself argued that humans
36:44evolved in Africa. His argument
36:46was simple. He had no fossils.
36:48But he said, look, gorillas and chimpanzees
36:50are our closest relatives
36:52among living animals. That's true.
36:54Gorillas and chimpanzees live only
36:56in Africa. There's no evidence they ever
36:58lived anywhere else, and therefore
37:00it is highly probable that humans evolved
37:02in Africa. And that's a good argument.
37:04It was a correct inference, and it turned out
37:06to be right. But the whole history
37:08after that was an attempt
37:10to deny it. The popular
37:12view always was,
37:14up until the realization
37:16of the meaning of the Australopithecines,
37:18that humans evolved in Asia. And
37:20basically that comes from the Aryan theory
37:22that what's good and white
37:24and cultured and
37:26linguistically superior
37:28arose in the Aryan region
37:30of Central Asia and India, spread out
37:32into Europe, and that anything else
37:34is a result of that spread and secondarily
37:36degenerate. The famous
37:38Gobi Desert expedition sent
37:40out by Henry Fairfield Osborne,
37:42one of the great scientific races
37:44of our century and president of the American
37:46Museum of Natural History, and led by
37:48Roy Chapman Andrews, who wrote a book
37:50with that wonderful imperialist
37:52title, The New Conquest of
37:54Central Asia. That expedition,
37:56which is in the lore, in the
37:58annals of natural history,
38:00one of the great success stories, was of course
38:02actually a failure. They found wonderful
38:04things. They found all the Ceratopsian dinosaurs
38:06and the first dinosaur eggs, but that's
38:08not why they went there.
38:10They went there to find the ancestors
38:12of man in Central Asia, where everybody
38:14knew they were. And they didn't find
38:16them, because humans evolved
38:18in Africa.
38:20Well, finally, of course,
38:22one had to admit,
38:24at least by the fifties, that these
38:26osteopithecines were older
38:28than the Homo erectus material that had
38:30been found in Asia, and were at least
38:32close to our lineage, and had to be
38:34seen as genuinely ancestral, and the Darwin
38:36had been right. So by the 1950s
38:38one had to admit that, and that
38:40stage of retreat was made.
38:42But, that didn't end it.
38:44It was still that second argument.
38:46Namely, okay,
38:48that's right, I mean humans evolved in
38:50Africa, but Homo sapiens
38:52evolved from Homo erectus.
38:54Homo erectus was the species that
38:56got out of Africa and moved elsewhere.
38:58Homo sapiens, our species,
39:00arose from Homo erectus
39:02in Asia.
39:04So you see, okay, we arose from the
39:06apes here, but we acquired
39:08our intelligence in the land of Asia
39:10and of Aryan supremacy.
39:12That's a very subtle distinction, you see.
39:14But then, of course, what's
39:16happened? Well, Homo erectus has been
39:18found in Africa. In fact, the oldest
39:20Homo erectus is right here in Africa.
39:22So it looks like Homo erectus evolved here
39:24and then migrated out. What about
39:26Homo sapiens? That's still not clear.
39:28But it's beginning to look as though the
39:30oldest Homo sapiens are probably here too.
39:32And that Homo sapiens
39:34probably evolved in Africa also.
39:36And that all species of humans evolved
39:38in Africa. And that the spread of Homo
39:40sapiens, like the
39:42prior spread of erectus, was a
39:44spread from Africa. And there's
39:46a second, the final retreat, the
39:48admission that indeed we
39:50evolved here, all of us.
39:52Gould writes
39:54extensively on the biological basis
39:56for human equality, pointing out
39:58that human races are remarkably similar
40:00genetically. He is
40:02a strong critic of biological determinism,
40:04a theory which he claims
40:06attributes social differences between human
40:08groups to inherited biology.
40:10One of his books is about
40:12intelligence testing and craniometry,
40:14a 19th century science of measuring
40:16intelligence by skull size.
40:18There is this myth
40:20about science that science is different, that
40:22it's objective, that there's a scientific
40:24method, that there are right answers,
40:26that there's a special way of doing things,
40:28that scientists are a priesthood
40:30that have latched on to
40:32an arcane set of
40:34techniques that enable them
40:36to find truth. Now, of course, science
40:38is trying to understand the truth
40:40of the world. And we do get there
40:42in fitful ways, but we're just
40:44human beings struggling, embedded
40:46in cultural and social contexts like
40:48everyone else. Trouble is, you can't
40:50analyze that at the present, because
40:52we don't know what our biases are.
40:54If we knew, we'd eliminate them.
40:56Looking back into the history of
40:58science provides a revealing glimpse
41:00of how cultural biases can distort
41:02our view of the truth.
41:04A few years ago,
41:06Gould wrote about a bit of scientific
41:08wishful thinking by an eminent
41:10historian who set out to measure the
41:12cranial capacities of various races.
41:14This is the story of
41:16Samuel George Morton. He's not a man
41:18well-known today, but was the leading
41:20American scientist of his day. He was a
41:22physician from Philadelphia.
41:24He decided, in the
41:261820s, the whole problem
41:28with the literature on
41:30racial capacities
41:32in terms of intelligence was there
41:34wasn't any data. There had been a lot of speculation
41:36in the literature. So he was going to get the data.
41:38For ten years, he assiduously
41:40collected human skulls.
41:42He just, after all, got the skulls
41:44and he measured them. It was absolutely objective.
41:46I just want to read to you from
41:48the introduction of his major treatise,
41:50the Cranioamericana, his treatise
41:52on the skulls of American Indian peoples,
41:54some of his characterizations
41:56of various peoples, which
41:58are amusing, and
42:00they're so obviously
42:02caught in the conventional
42:04stereotypical prejudices, and we can recognize this
42:06today, that if Morton, in spite of
42:08these statements, was seen as the great objectivist,
42:10these statements were clearly
42:12taken as mere indications of fact.
42:14For example, here's what he
42:16says about the, quote, Greenland Eskimo.
42:18They are crafty, sensual, ungrateful,
42:20obstinate, and unfeeling.
42:22In gluttony, selfishness, and ingratitude,
42:24they are perhaps unequaled by any
42:26other nation of people, except
42:28for the Hottentots,
42:30of whom he wrote,
42:32they are the nearest approximation
42:34to the lower animals. Their complexion
42:36is a yellowish brown, compared
42:38by travelers to the peculiar hue
42:40of Europeans in the last stages of jaundice.
42:42His claim
42:44was that the average for whites
42:46was 87 cubic inches,
42:48for Indians, American Indians,
42:5080 cubic inches, for blacks,
42:5278 cubic inches. Big
42:54differences, and just in the
42:56order he wanted, whites, Indians,
42:58and blacks. I
43:00presume you know how you go about this exercise.
43:02You get a skull, you pour
43:04something in through the foramen magnum,
43:08eventually pour it out
43:10again, measure it, a beaker.
43:12Morton began by using
43:14white mustard seed, but abandoned it
43:16because the grains were too light and uneven
43:18in size, and eventually moved
43:20to lead shot. What I did
43:22was to reanalyze Morton's
43:24data one summer, a few years back,
43:26and I discovered that
43:28his ranking of whites,
43:30Indians, and blacks was based more
43:32on his hopes than on any reality
43:34of his data. So I asked,
43:36why did Indians end up so much below
43:38whites? And the answer was that
43:40if you look at Morton's sample, it was very
43:42heavily weighted. About
43:4425 to 30 percent were
43:46made up of people whom he called Inca-Peruvians,
43:48a group of people who were very
43:50short. Small-sized people
43:52have small-sized brains. It had nothing to do with intelligence.
43:54Brain size correlates with body size.
43:56You have to make a correction. Morton never made it.
43:58The story for the blacks is even
44:00more interesting. As I said, Morton
44:02first used a method of
44:04mustard seed, which he later abandoned as
44:06inaccurate, and when he measured with mustard seed,
44:08he found that black skulls
44:10were on the average five cubic inches
44:12lower than whites.
44:14He remeasured them with lead shot, which is
44:16accurate, though he never did
44:18the tapulations again, and the difference
44:20falls to about one cubic
44:22inch. That means
44:24when he was using a subjective method that
44:26could be unconsciously fudged, he got a
44:28five cubic inch difference. When he used
44:30an objective method, there was almost
44:32no difference. Now, that's
44:34real interesting. See, when he could fudge the measure
44:36unconsciously,
44:38there was that 5.4 cubic inch
44:40disparity, which means he was systematically
44:42to the tune of three or four cubic inches,
44:44under-measuring the skulls of black people.
44:46Now, how did that happen?
44:48I mean, how did he do it? He wasn't doing it consciously.
44:50I'm sure he wasn't. But you start thinking
44:52about it, and, you know,
44:54you start constructing how it might happen.
44:56Morton picks up a skull of a
44:58black man. Gee, it looks kind of disconcertingly
45:00large. He's a little worried about it.
45:02You pour in the mustard seed. You shake
45:04it very gently to try and get it to settle.
45:06Pour it out again.
45:08Then you pick up a white skull, which is
45:10disconcertingly small,
45:12and you pour in the mustard seed.
45:14You take your thumb, and you push on the
45:16foramen magnum as hard as you can.
45:18You push it down. You pour in.
45:20It's not hard. I mean, that must have been what happened.
45:22Now, I don't think Morton, and this is
45:24the interesting thing about the story.
45:26It's not a question of conscious fraud, so far
45:28as I can tell. Conscious fraud isn't historically
45:30interesting. A person who fakes on purpose knows
45:32what he's doing. But unconscious
45:34finagling is fascinating.
45:36And in Morton's case, since he published all his
45:38data, and I could extract the errors,
45:40I assume he didn't know what he was doing.
45:42A person who's committing conscious fraud tries to cover
45:44his tracks. I think Morton
45:46believed that he was proceeding in total
45:48honesty, but was so blinded
45:50by the prejudices of his time
45:52and his personal expectations that he ended
45:54up with the results he expected,
45:56even though when you reanalyze the data that
45:58he himself presents, you realize there's no
46:00difference among races
46:02in cranial capacity.
46:04There's astonishingly little
46:06variation among
46:08so-called human races. There's a whole lot
46:10of variation within each racial group.
46:12In fact, there is so much variation
46:14within each racial group that it just
46:16swamps the minor differences
46:18between them. You know what
46:20really matters is details. I think
46:22it was Mies van der Rohe, the
46:24architect, who said that God dwells in the
46:26details, and that's one of the more profound
46:28statements that's ever been made.
46:30You see, what really matters, of
46:32course, about biological
46:34determinism is how it affects people,
46:36how it affects individuals.
46:38Individual human
46:40beings, as I said, come through this
46:42world only once, so far as
46:44we know. If their lives are thwarted
46:46by
46:48a stricture imposed
46:50from without, for social
46:52reasons but falsely identified as
46:54lying within, they never get another
46:56chance. That's it.
46:58That's the greatest tragedy
47:00that biological determinism has imposed
47:02upon the lives of millions of people.
47:04Morton's story remains
47:06relevant today. Fortunately,
47:08we've come somewhere in learning about
47:10human racial variation,
47:12and we don't find any more
47:14as we did in the 19th century,
47:16the official policy of nation
47:18after nation in the West, based on
47:20explicit views of
47:22a chain of advance
47:24rising up to white males at the
47:26top. Thank goodness we're beyond that.
47:28Although, that is still largely
47:30the policy of the South African
47:32government today. But
47:34at least for this country, I think
47:36the main lingering effect of
47:38biological determinism
47:40is the belief of millions and millions
47:42of people that
47:44biology puts
47:46a fixed limit on what people
47:48can do. Millions of people in this nation
47:50learn their IQ scores and
47:52choose not to strive or are
47:54channeled into
47:56positions less
47:58suited than what they could do
48:00as a result of this mistaken
48:02belief that you
48:04can put a biological
48:06number on people representing the
48:08limits of their potential achievement.
48:11Gould believes that science is
48:13a creative human enterprise,
48:15but it is also the search for an
48:17objective truth.
48:19He argues that the history of life is
48:21relevant and can inform the decisions
48:23we make in the present.
48:25Long before human life began
48:27comes a story from the past
48:29which may bear a direct connection to
48:31our own lives in the future.
48:33For a hundred million years,
48:35there were giants on the earth,
48:37and then there were none.
48:39What caused the extinction of dinosaurs
48:41has been the greatest unsolved
48:43mystery of paleontology.
48:45When dinosaurs became extinct
48:47some 65 million years
48:49ago, we
48:51seem to have evidence now
48:53that a giant extraterrestrial body,
48:55either an asteroid or some
48:57comets hit the earth at that time, but why
48:59should that cause an extinction?
49:01Asteroid might kill a Tyrannosaurus or two,
49:03but why should it propagate its effects
49:05throughout the earth?
49:07There's been lots of discussion
49:09of the killing scenario
49:11involved in such an impact,
49:13and the idea first proposed
49:15by Louis and Walter Alvarez
49:17when they developed the impact theory
49:19is that a large asteroid
49:21or comet striking the earth would send
49:23aloft a cloud of dust
49:25so profound and thick
49:27that light would be cut off,
49:29temperatures would fall,
49:31photosynthesis would fail, and this
49:33would propagate through effects
49:35of climate and photosynthesis
49:37a wave of extinctions.
49:39Interestingly enough, that's the very same
49:41scenario that has been
49:43suggested as
49:45the likely result of a major
49:47nuclear war.
49:49It turns out that nuclear
49:51bombs send dust up in the atmosphere
49:53and by causing cities to burn
49:55send a lot of soot into lower regions
49:57of the atmosphere, and our best
49:59models indicate that
50:01the so-called nuclear winter would come about
50:03for the same reasons
50:05that the comet or asteroid
50:07striking the earth 65 million years ago
50:09might have wiped dinosaurs out.
50:11Indeed, the experiment of nuclear winter
50:13has probably been made upon our earth
50:15and perhaps often.
50:17The geological record is punctuated
50:19by events of mass extinction, perhaps
50:21occurring at regular intervals of 26 million
50:23years, and wiping out in the worst
50:25case, and this is not a conjecture,
50:27this is a measurement, as many as
50:2995% of marine invertebrate
50:31species.
50:33Gould was recently called to Washington
50:35to testify before a congressional subcommittee.
50:37He spoke about the possible
50:39biological consequences
50:41of a nuclear war.
50:43What we can say, virtually
50:45for certain, is that the biological
50:47impact will be severe, perhaps
50:49irreversibly disastrous, as in the
50:51mass extinctions of our geological record.
50:53In any large-scale nuclear
50:55exchange between the superpowers,
50:57global environmental change is sufficient
50:59to cause the extinction of a major fraction
51:01of the plant and animal species on the earth
51:03are likely. In that event, the possibility
51:05of the extinction of homo sapiens
51:07cannot be excluded.
51:09There has been some controversy within
51:11the scientific community over various
51:13scenarios for nuclear winter.
51:15But the fossil record, the archive
51:17of the history of life on earth,
51:19shows clear evidence of mass
51:21extinctions.
51:23The extinction of dinosaurs
51:25set the evolutionary stage
51:27for our own existence.
51:29It's a widely underappreciated
51:31fact, and something that people really ought
51:33to know about, because it would
51:35contradict one of the great biases
51:37that we have in trying to see
51:39ourselves as the end product
51:41of a progressive evolutionary sequence,
51:43that, in fact, mammals didn't
51:45out-compete dinosaurs. Mammals,
51:47in fact, evolved at the same time as
51:49dinosaurs. And they lived for a hundred
51:51million years as small creatures, no
51:53bigger than that for the largest,
51:55in the nooks and crannies of an ecological
51:57sphere dominated by dinosaurs.
51:59They didn't drive dinosaurs out. They weren't
52:01getting anywhere, so to speak, versus
52:03dinosaurs. Had some
52:05external force not intervened
52:0765 million years ago to wipe out dinosaurs
52:09and clear away enough space
52:11so that mammals could take over,
52:13I suspect the world would still be dominated
52:15by dinosaurs, and mammals would still be rat-sized
52:17creatures of no consciousness,
52:19and we wouldn't be here doing this film.
52:21Had it not been for that asteroid
52:23or cometary shower that wiped out the
52:25dinosaurs, we would not be here.
52:27You have been reading, I'm sure,
52:29many times in the last few months
52:31about the rather frightening
52:33prospect of nuclear winter,
52:35the recognition that, although we always
52:37knew it was bad, that half the
52:39world's population might well die outright
52:41in an all-out nuclear exchange, and it's
52:43far even worse, that there are
52:45long-term climatic consequences that
52:47we have never considered, that in
52:49even a small nuclear change,
52:51exchange is quite possible, given
52:53the volumes of dust and soot that would be sent
52:55aloft, that a dust cloud might
52:57blanket the earth, making it so cold
52:59and dark for sufficiently long
53:01that even those who survived the immediate
53:03attack might not ultimately
53:05make it. That argument
53:07of nuclear winter, frightening though it is, I
53:09hope and I trust, will not only
53:11serve as an important argument in our struggles
53:13to end the horror of nuclear
53:15holocaust, but has also, I hope, brought our world
53:17together, because for the first time
53:19everybody suffers, for the first
53:21time nations in the southern hemisphere
53:23that might have said, I hope they don't
53:25do it, that if they wipe themselves out, at least we'll
53:27be here, that is not so, necessarily,
53:29we are all in this together, we are
53:31indeed one world.
53:33Now, if that sounds familiar,
53:35dust clouds due to dust and
53:37soot going up due to explosions,
53:39that sounds familiar, it indeed is,
53:41because it is the Alvarez scenario,
53:43and that's where it came from,
53:45and that's the point. And I might say in
53:47conclusion that it amuses me greatly,
53:49and I think it indicates the
53:51coherence of good science, its
53:53integrative capacities, to
53:55recognize, and this is what
53:57appeals to me so
53:59much, that if indeed
54:01the nuclear
54:03winter argument helps to save
54:05us, I'm not so naive as to think the
54:07recognition of nuclear winter will tip the balance,
54:09it will be just one component
54:11in this struggle we must all fight
54:13to assure that the horror of nuclear war
54:15does not happen, but I hope that the argument from nuclear
54:17winter will help us to avoid
54:19that catastrophe and to save ourselves,
54:21and it amuses me and intrigues me
54:23and impresses me with the unity of knowledge, no
54:25end, to think that the asteroid
54:27or the comets that made
54:29our own lives possible,
54:31may, through the impetus they gave
54:33to the development of the scenario of nuclear
54:35winter, now help to save
54:37us again. Thank you.
54:45Thank you.
54:53And right at the
54:55rocks that are of the age where the dinosaurs
54:57became extinct, you see a tremendous rise
54:59in this element of iridium which almost had to
55:01come from elsewhere, so it really looks as
55:03that old science fiction scenario
55:05is right, that some comet
55:07or asteroid hit the earth and wiped the dinosaurs
55:09out, which is good because it gave us
55:11a chance, otherwise the mammals
55:13otherwise the mammals probably wouldn't have made it
55:15and we wouldn't have yet, so
55:17it's real fascinating.
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