by Carl Sagan
Taken together, these dramatic societal shifts—often in ten generations or less—provide a compelling refutation of the claim that we are condemned, without hope of reprieve, to live out our lives in a barely disguised chimpanzee social order. Moreover, the shifts are occurring so swiftly that they cannot possibly be due to natural selection. Instead, our culture must be drawing forth propensities and predispositions that already reside deep within us.
We humans hold at least 99.9% of our DNA sequences in common. We are far more closely related to one another than we are to any other animal. By the similarity standards we use in other matters, humans—even of the most disparate cultures and ethnic origins—are essentially identical in our heredities. Of the immense number of possible beings, realized and unrealized, we all are cut from the same cloth, made on the same pattern, granted the same strengths and weaknesses, and will ultimately share the same fate. Given the reality of our mutual interdependence, our intelligence, and what is at stake, are we really unable to break out of behavior patterns evolved to benefit our ancestors of long ago?
We have been dismantling ancient institutions that no longer serve, and are tentatively trying out others. Our species is becoming an intercommunicating whole, with powerful economic and cultural bonds linking up the planet. Our problems, increasingly, are global in venue, admitting only global solutions. We have been uncovering the mysteries of our past and the nature of the Universe around us. We have invented tools of awesome power. We have explored the nearby worlds and have set sail for the stars. Granted, prophecy is a lost art and we are not vouchsafed an unclouded view of our future. Indeed, we are almost wholly ignorant of what is coming. But by what right, what argument can pessimism be justified? Whatever else may be hidden in those shadows, our ancestors have bequeathed us—within certain limits, to be sure—the ability to change our institutions and ourselves. Nothing is preordained.
We achieve some measure of adulthood when we recognize our parents as they really were, without sentimentalizing or mythologizing, but also without blaming them unfairly for our imperfections. Maturity entails a readiness, painful and wrenching though it may be, to look squarely into the long dark places, into the fearsome shadows. In this act of ancestral remembrance and acceptance may be found a light by which to see our children safely home.
EPILOGUE
It is not possible to be ignorant of the end of
things if we know their beginning.
THOMAS AQUINAS
Summa Theologica1
We have described the Earth before humans set foot upon it. We have tried to understand something about our ancestors, using as our guide the fossil record and the gorgeous panorama of life that now graces our planet. While there are still vast numbers of missing pages in our orphan’s file, the progress of science has enabled us to glimpse a few of the lost or forgotten entries—perhaps even many of the important items. But we have explored only the early chapters of the file. Its key central section—chronicling the dawn of our species and its evolution up to the invention of civilization—is the subject of the next book in this series.
Notes
Prologue
THE ORPHAN’S FILE
1. Attributed to Empedocles by Sextus Empiricus, in Against the Mathematicians, VII, 122–125, in Jonathan Barnes, editor and translator, Early Greek Philosophy (Harmondsworth, Middlesex, England: Penguin Books, 1987), p. 163.
2. Science and Humanism (Cambridge: Cambridge University Press, 1951). Schrödinger was one of the discoverers of quantum mechanics.
3. In many scientific accounts of the origin of the human species, there is a story something like this. (Cf., e.g., Misia Landau, Narratives of Human Evolution [New Haven and London: Yale University Press, 1991].) But rather than being imposed on the evidence, we hold that it flows naturally out of the evidence. Human origins have in fact been very humble. We have in fact, by many standards, become the dominant species on the planet, and done it partly by dint of our own efforts. We are in fact profoundly ignorant of many of the details of our origins. It is natural to represent ourselves in metaphor as a favored child brought up in obscure circumstances, and then as hero venturing forth into the world to seek our identity. The principal danger of the metaphor would be if we thought our success due to one generation or people or nation; or if our success were to blind us to the danger we have placed ourselves in.
4. Robert Redfield, The Primitive World and Its Transformations (Ithaca, NY: Cornell University Press, 1953), p. 108.
5. Fyodor Dostoyevsky, Brothers Karamazov (1880), translated by Richard Pevear and Larissa Volokhonsky (San Francisco: North Point Press, 1990), Book Six, Chapter 3, p. 318.
6. Mary Midgley, Beast and Man: The Roots of Human Nature (Ithaca, NY: Cornell University Press, 1978), pp. 4, 5.
7. A similar metaphor was employed in The Origin of Species, Chapter 10, where Charles Darwin compared the geological record to “a history of the world imperfectly kept, and written in a changing dialect; of this history, we possess the last volume alone … Only here and there a short chapter has been preserved; and of each page only here and there a few lines.”
Chapter 1
ON EARTH AS IT IS IN HEAVEN
1. In Lucien Stryk and Takashi Ikemoto, translators, Zen Poems of China and Japan: The Crane’s Bill (New York: Grove Press, 1973), p. 20.
2. Translated by Dennis Tedlock (New York: Simon and Schuster/Touchstone, 1985, 1986), p. 73.
3. What we are describing here is the origin of our Solar System—not the origin of the Universe, or at least its latest incarnation, which is most often described as the Big Bang.
4. The Second Law of Thermodynamics specifies that in any process, the net orderliness of the Universe must decrease. Some places may get more orderly as long as others get more chaotic. There is plenty of order to draw on in the Universe, and nothing in the Second Law is inconsistent with the origin of the planets or the beginnings of life.
5. Except for a tiny fraction generated by the radioactive decay of atoms hailing originally from elsewhere in the Galaxy.
6. Two millennia after his last worshipper died, the name of this god was given to a newly discovered planet.
Chapter 2
SNOWFLAKES FALLEN ON THE HEARTH
1. Translated by Dennis Tedlock (New York: Simon and Schuster/Touchstone, 1985, 1986), p. 72.
2. In Just So Stories (New York: Doubleday, Page & Company, 1902), p. 171.
3. The image of an hour’s drive up or down is, so far as we know, originally due to the astronomer Fred Hoyle.
4. Suppose, for the sake of argument, that the primeval sea had just the same size and depth as our present ocean. Suppose also that the organic molecules on the primitive Earth, in the absence of any life to eat them up, lasted about 10 million years before they fell to pieces from molecular old age, or were carried down toward the Earth’s molten interior. Then, in the best case, the primitive oceans would have been about a 0.1% solution of organic matter (about the consistency of a very thin beef broth). For the whole world ocean. Some lakes, bays, and inlets may have been a much more concentrated solution of organic molecules. (Christopher Chyba and Carl Sagan, “Endogenous Production, Exogenous Delivery, and Impact-Shock Synthesis of Organic Molecules: An Inventory for the Origins of Life,” Nature 355 [1992], pp. 125–132.)
5. D. H. Erwin, “The End-Permian Mass Extinction,” Annual Review of Ecology and Systematics 21 (1990), pp. 69–91.
6. The end-Permian catastrophe was far more severe than the end-Cretaceous catastrophe some 200 million years later in which all the dinosaurs died.
7. Marcus Aurelius, Marcus Aurelius: Meditations, IV, 48, translated by Maxwell Staniforth (Harmondsworth, UK: Penguin Books, 1964), quoted in Michael Grant, ed., Greek Literature: An Anthology (London and Harmondsworth, Middlesex, England: Penguin Books, 1977), p. 430.
8. The Venerable Bede, The Ecclesiastical History of the English Nation (Historia Ecclesiastica) (London: J. M. Dent, 1910, 1935)
(written in 732), Book II, Chapter XIII, p. 91.
Chapter 3
“WHAT MAKEST THOU?”
1. And still it burns. On the day we write this, the authors received yet another expression of outrage from a viewer offended by the endorsement of evolution in our Cosmos television series. “We teach our children that they are descended from monkeys, and then are surprised when they act accordingly,” he writes. “Throw out an absolute standard of morality, make all behavior relative, and the result must be moral chaos.” He offers no critique of the evidence for evolution, but only of its imagined social consequences.
Even today, some American high school biology curricula are still giving equal time to special creation (and to a subject oxymoronically called “scientific creationism”). Should time also be devoted in school geography curricula to the evidence for the proposition that the Earth is flat?—a view clearly held by the authors of the Bible and still supported by fringe advocacy groups. Both special creation and the flat Earth hypothesis were reasonable scientific guesses in the sixth century B.C., when Genesis was compiled. They are no longer.
Standard works defending creationism include D. T. Gish, Evolution? The Fossils Say No! (San Diego: Creation Life Publishers, 1979), and H. M. Morris, Scientific Creationism (ibid, 1974). Among the many refutations by scientists are A. N. Strahler, Science and Earth History (Buffalo, N.Y.: Prometheus, 1987); D. J. Futuyama, Science on Trial: The Case for Evolution (New York: Pantheon, 1983); G. B. Dalrymple, The Age of the Earth (Stanford, CA: Stanford University Press, 1991); Tim M. Berra, Evolution and the Myth of Creationism (ibid, 1990); and a forthright pamphlet by the National Academy of Sciences, Science and Creationism (Washington, D.C.: National Academy Press, 1984) that describes special creation as “an invalidated hypothesis,” and concludes: “No body of beliefs that has its origin in doctrinal material [such as the Bible] rather than scientific observation should be admissible as science … Incorporating the teaching of such doctrines into a science curriculum stifles the development of critical thinking … and seriously compromises the best interests of public education.” Among the many virtues of Berra’s book is its dedication (“For my mother, who allowed me to read during meals”).
In a 1982 Gallup poll, 44% of American respondents supported the statement “God created man pretty much in his present form at one time within the last ten thousand years.” Only 9% supported the statement “Man has developed over millions of years from less advanced forms of life. God had no part in this process.” (Creation/Evolution, No. 10 [Fall 1982], p. 38.)
In a 1988 survey of 43 members of the U.S. Congress who chose to answer a questionnaire, 88% felt that “modern evolutionary theory has a valid scientific foundation,” but less than half could say, even roughly, what the basic idea of evolution might be. Only one in three strongly agreed with the statement that the Earth was 4 to 5 billion years old. In an identical survey of a quarter of the members of the Ohio legislature, the corresponding numbers were 74%, 23%, and 23%. (Michael Zimmerman, “A Survey of Pseudoscientific Sentiments of Elected Officials,” Creation/Evolution, No. 29 [Winter 1991/1992], pp. 26–45.)
2. Erasmus Darwin, The Botanic Garden, Part II, The Loves of the Plants (1789), Canto III, line 456; in Desmond King-Hele, editor, The Essential Writings of Erasmus Darwin (London: MacGibbon & Kee, 1968), p. 149.
3. Dumas Malone, Jefferson and His Time, Volume One, Jefferson the Virginian (Boston: Little, Brown, 1948), p. 52.
4. Gerhard Wichler, Charles Darwin: The Founder of the Theory of Evolution and Natural Selection (Oxford: Pergamon Press, 1961), p. 23.
5. London, 1803 (published posthumously). Quoted in Howard E. Gruber, Darwin on Man: A Psychological Study of Scientific Creativity (Chicago: The University of Chicago Press, 1974), p. 50.
6. This example is from J. B. S. Haldane, The Causes of Evolution (New York: Harper, 1932), p. 130.
7. And in August Weismann’s late-nineteenth-century experiment, five successive generations of mice had their tails cut off with no effect on the progeny. George Bernard Shaw dismissed such examples as missing Lamarck’s point: The mice do not aspire to be tailless, as the giraffes are purported to strive for long necks (Back to Methuselah: A Metabiological Pentateuch [New York: Brentano’s, 1929]). This is magical thinking. Surviving incarnations of Lamarck’s hypothesis include the idea that the disobedience of Adam in the Garden of Eden caused an “original sin” genetically propagated to future generations (accepted by the Catholic Church at the Council of Trent and reaffirmed in a 1950 papal encyclical of Pius XII); and the fraudulent agricultural genetics of Stalin’s favorite pseudoscientist, Trofim Lysenko. Nevertheless, the inheritance of acquired characteristics—while apparently wrong at the level of the organism—may be right at the level of the gene: A mutation is a chemical accident slightly changing the structure of a gene. Descendent genes inherit the accident. But the knife of August Weismann was too blunt to reach into the genes.
8. Sir Francis Darwin, editor, Charles Darwin’s Autobiography, with His Notes and Letters Depicting the Growth of the ORIGIN OF SPECIES (New York: Henry Schuman, 1950), pp. 29, 30.
9. Ibid., pp. 34, 35.
10. John Bowlby, Charles Darwin: A New Life (New York: W. W. Norton, 1990), p. 110.
11. Ibid., p. 118.
12. Charles Darwin’s Autobiography, p. 33.
13. Ibid., p. 37.
14. Stephen Jay Gould, Ever Since Darwin (New York: Norton, 1977), p. 33.
15. Charles Darwin, The Voyage of the Beagle (London: J. M. Dent & Sons Ltd., 1906), p. 18.
16. Frank H. T. Rhodes, “Darwin’s Search for a Theory of the Earth: Symmetry, Simplicity and Speculation,” British Journal of the History of Science 24 (1991), pp. 193–229.
17. The Autobiography of Charles Darwin (unexpurgated edition edited by Nora Barlow, his granddaughter) (New York: Harcourt Brace, 1958), p. 95.
18. Bowlby, op. cit., p. 233.
19. Francis Darwin, editor, The Life and Letters of Charles Darwin (London: John Murray, 1888), Volume II, p. 16.
20. Ronald W. Clark, The Survival of Charles Darwin: A Biography of a Man and an Idea (New York: Random House, 1984), p. 90.
21. Ibid., pp. 90, 91.
22. Ibid., p. 105.
23. An excerpt from Wallace’s article:
“Wild cats are prolific and have few enemies; why then are they never as abundant as rabbits? The only intelligible answer is, that their supply of food is more precarious. It appears evident, therefore, that so long as a country remains physically unchanged, the numbers of its animal population cannot materially increase. If one species does so, some others requiring the same kind of food must diminish in proportion. The numbers that die annually must be immense; and as the individual existence of each animal depends upon itself, those that die must be the weakest—the very young, the aged, and the diseased,—while those that prolong their existence can only be the most perfect in health and vigour—those who are best able to obtain food regularly, and avoid their numerous enemies. It is, as we commenced by remarking, ‘a struggle for existence,’ in which the weakest and least perfectly organized must always succumb …” (Alfred Russel Wallace, “On the Tendency of Varieties to Depart Indefinitely from the Original Type” [Wallace’s contribution to Darwin and Wallace, “On the Tendency of Species to Form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection”], in Journal of the Proceedings of the Linnean Society: Zoology, Volume III [London: Longman, Brown, Green, Longmans & Roberts, and Williams and Norgate, 1859], pp. 56, 57.)
24. In subsequent editions, the sentence was amended to read “Much light will be thrown on the origin of man and his history” (our emphasis).
Chapter 4
A GOSPEL OF DIRT
1. In Philosophical Works, with Notes and Supplementary Dissertations by Sir William Hamilton, with an Introduction by Harry M. Bracken, 2 volumes (Hildesheim: Georg Olms Verlagsbuchhandlung, 1967), Vol. 1, p. 52.
2
. Charles Darwin, The Origin of Species by Means of Natural Selection or the Preservation of Favored Races in the Struggle for Life (New York: The Modern Library, n.d.) (originally published in 1859) (Modern Library edition also contains The Descent of Man and Selection in Relation to Sex), Chapter XV, “Recapitulation and Conclusion,” p. 371.
3. Of course, the traditional religious understanding of adaptation has been God’s will. However, this is not an explication of process.
4. Unattributed quotations in this chapter are excerpted from Charles Darwin, op. cit., pp. 29, 31, 33, 34, 64–67, 359, and 370; and from Charles Darwin and Alfred R. Wallace, “On the Tendency of Species to Form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection,” Journal of the Proceedings of the Linnean Society: Zoology, Volume III (London: Longman, Brown, Green, Longmans & Roberts, and Williams and Norgate, 1859), p. 51.
5. Francis Darwin, editor, The Life and Letters of Charles Darwin (John Murray: London, 1888), Volume III, p. 18.
6. The Westminster Review 143 (January 1860), pp. 165–168.
7. The Edinburgh Review 226 (April 1860), pp. 251–275.
8. John A. Endler’s Natural Selection in the Wild (Princeton: Princeton University Press, 1986) provides a useful modern summary of what natural selection is and isn’t, its role in evolution, and how to test that it operates. His Table 5.1, culled from the recent scientific literature, summarizes over 160 “direct demonstrations” of natural selection in the wild.