The discovery by a team of Indonesian and Australian researchers of the remains of a previously unknown species of hominid, Homo floresiensis, on the Indonesian island of Flores was characterized by some scholars as the greatest discovery in anthropology in a half-century and was selected by Science magazine as the leading runner-up for the 2004 breakthrough of the year (first place went to the discoveries of the Mars Exploration Rovers that indicate Mars was once wetter than it is today and potentially capable of supporting life). The discoverers of the new species note that it was a particularly small hominid, with an adult stature of approximately one meter and an endocranial volume of about 380 cm3, less than one-third that of the typical modern human and even small relative to its body size. They argue that it is most likely a descendant of Homo erectus that evolved in long-term isolation, with subsequent endemic dwarfing. Another interesting aspect of the find is that Homo floresiensis apparently lived until at least 18,000 years ago and was, therefore, a contemporary of anatomically modern humans. Many scholars where shocked by both the small stature of and late date attributed to the new hominid, with some moved to question whether the remains were not merely those of a deformed modern human, a suggestion that its discoverers reject as unsupported by the evidence.1
Despite the unusual character of this find, should we be surprised that our genus, Homo, spawned a dwarf species that was contemporaneous with Homo sapiens for a long stretch of our evolutionary history? The late Stephen Jay Gould, renowned dialectical biologist and evolutionary theorist, would surely have said no. What we see as a surprise can reveal a great deal about our underlying, and often unconscious, assumptions about the world. The discovery of Homo floresiensis is only particularly surprising from a bourgeois perspective, with its paradigmatic assumption that history necessarily unfolds in a progressive manner, leading inexorably to our contemporary world. Gould was one of the best-known critics of this worldview, and he surely would have both welcomed the discovery of Homo floresiensis and been entirely unsurprised by it.
Stephen Jay Gould was a lifelong intellectual protagonist of the left and his loss to cancer in 2002 has been greatly felt, as is demonstrated by the touching memorial to him published in the November 2002 issue of MR by his colleagues Richard Lewontin and Richard Levins. Although he is lost to us, his carefully developed worldview lives on through his extensive and enduring written work. The application of his intellectual perspective to understanding nature and society remains as pertinent as ever. Gould would certainly have written about Homo floresiensis if he was still with us, and his insights are invaluable to the maintenance and development of a dialectical science of human origins.
Gould and his close colleague Niles Eldredge—who together developed the theory of punctuated equilibria, which suggests that rather than following a process of Darwinian gradualism, the evolution of a typical species is best characterized by periods of geologically rapid change followed by long periods of stasis, with most change occurring at the point of speciation—have noted the bourgeois character of traditional Darwinism and acknowledged the link between their particular view of natural history and Marxism. That is not to say that they imposed, or condoned the imposition of, social views on the natural world, but to note that they recognized the socially embedded nature of science. Gould and Eldredge knew well that social philosophies not only inhibit our perception of certain facts of nature—such as how Darwin’s social context likely made him unable fully to recognize the lack of progressive drive in evolutionary history—they also help us to see things that we might otherwise miss, such as how historical materialism’s focus on revolutionary change in social history helped to open the eyes of Marxist scholars to the possibility that organic evolution proceeds in the manner proposed by the theory of punctuated equilibria. Gould’s perspective, stemming from the Marxist tradition, helps us to recognize the important implications of the discovery of Homo floresiensis, implications that may be missed by less critical scientists.
A theme that runs through nearly all of Gould’s work is that the present is the product of innumerable contingent events, and, therefore, we live in only one of many possible worlds. Gould and Lewontin penned a famous critique of what they termed the Panglossian Paradigm, the hyper-functionalist view, which is so common in bourgeois society, that our world is the only way it could be, and that it therefore reflects an inevitable natural order. Counter to the Panglossian Paradigm, Gould argued that the unfolding of natural history, and by extension human history, is not properly characterized by a progressive, directional trend, but rather as a wandering across the landscape of possibility governed predominantly by happenstance. From early in his career, Gould emphasized the importance of recognizing that the evolutionary process was best characterized as a metaphorical bush, with copious branches, rather than by a ladder, with its implication of clear directional progress to a higher status. Applying this point to human evolution, he argued that the evolutionary development of our species was not a linear march to our current form, but rather a process of diversification of hominid species and subsequent pruning of lineages through extinction, with the present point in time, where we are the only extant hominid, being historically atypical.2
Gould’s writing has already proven prophetic at least once, when evidence was reported in 1996 that suggested Homo erectus survived on the island of Java until perhaps as recently as 27,000 years ago, and, therefore, may have shared the world with Homo sapiens for well over 100,000 years. This find prompted Gould to note that as recently as 40,000 years ago there were at least three coexisting human species, Homo neanderthalensis in Europe, Homo erectus in Asia, and Homo sapiens spreading out of Africa into other parts of the inhabitable world.3 The discovery of Homo floresiensis adds a fourth member of our genus to this same period, with its discoverers suggesting that the remains of still further species of hominids may be found on other islands in the Malay Archipelago. The mass of accumulated evidence suggests quite forcefully, therefore, that Gould called it correctly long ago: modern humans are not the product of a linear march of progress, but rather one twig on the hominid bush that merely had the good fortune to survive to the present.
In addition to the coexistence of at least four human species in the recent past, the dwarfism of Homo floresiensis further makes the point that there is no necessary direction in the evolutionary process. Since Homo erectus apparently spawned not only large-brained modern humans, but also a descendant with a remarkably small brain (even smaller than would be expected based on its diminished physical stature), there was clearly no inherent evolutionary drive toward larger brains among our ancestors. As the prominent scholar Jared Diamond has noted, we should not be particularly surprised by the apparent fact that our ancestor Homo erectus spawned a micropygmy population, since it is well-known that large mammals colonizing remote small islands tend to evolve into isolated populations of dwarfs, with examples including pygmy hippos and elephants.4 It is only because of the widely held notion that the modern world is the inevitable outcome of a natural progressive drive that the bushiness of our family tree and the small physical and mental stature of one of our evolutionary cousins come as a surprise at all.
The Homo floresiensis find should also draw our attention to the remarkable unity of all contemporary humanity, since it sheds further light on the origin of modern humans. Scholars in the multiregionalist tradition have long claimed that modern human populations descended from regional populations of Homo erectus that evolved in parallel over hundreds of thousands of years, with modest genetic exchange across populations. Multiregionalists adhere to the position that the division of humans into distinct groups (races) is very old, which implies that genuine biological differences exist among contemporary races. This perspective parallels a view common before the rise of Darwinism known as polygenism, which asserted that each human race was the product of a separate divine creation, and that, therefore, human races are in fact separate (hierarchically orderable) biological species. After evolutionary theory became widely accepted, multiregionalism arose as a scientific version of polygenism. It is important to note in all fairness that contemporary supporters of multiregionalism typically deny any support for racist views or policies and acknowledge the high level of genetic similarity among human populations, but the multiregionalist position does, nonetheless, reify divisions of humans into distinct biological races (if not species).
The combination of recent paleontological and genetic evidence has made the multiregionalist explanation of human origins increasingly untenable, supporting, rather, the argument that all modern humans share a very recent (in geological terms) common ancestor who lived in Eastern or Southern Africa approximately a quarter of a million years ago and whose descendants spread out of Africa around 100,000 years ago, eventually replacing all other human groups. As some anthropologists have noted, the find of Homo floresiensis puts yet another (the last?) nail in the multiregional coffin, since it demonstrates the recent existence of human groups in various regions of the world that were entirely distinct from modern humans and could not have exchanged genes with our recent ancestors.5 The weight of current evidence, then, points to the conclusion that regional populations of Homo erectus, Homo neanderthalensis, and Homo floresiensis did not slowly blur into regional populations of Homo sapiens, but rather were distinct contemporaries of modern humans until very recently. Therefore, regional populations of modern humans do not share a continuous ancestry with the populations of Homo erectus that spread out of Africa one to two million years ago, but, rather, with Homo sapiens who migrated out of Africa only a geological eye-blink ago.
As Stephen Jay Gould argued two decades ago, human equality is a contingent fact of history. We could have lived in a world where divisions among human groups occurred long ago, and, therefore, races were truly biologically distinct. We do not, however, live in such a world due to the quirks of history. We live in a world where all humans are remarkably similar genetically and where race as a biological reality is an illusion. If populations of Homo erectus or Homo floresiensis had survived to the present, we may have been faced with genuine moral dilemmas of how to deal with fellow humans of a truly different nature. But we are fortunate that we do not face such dilemmas, and we should rejoice in our unity. Gould expressed the lesson well:
If our current times are peculiar in substituting the bushy richness of most human history with an unusual biological unity to undergird our fascinating cultural diversity, why not take advantage of this gift? We didn’t even have such an option during most of our tenure on Earth, but now we do. Why, then, have we more often failed than succeeded in the major salutary opportunity offered by our biological unity? We could do it; we really could. Why not try sistership; why not brotherhood?6
- The key sources on Science magazine’s breakthrough of the year and the discovery and analysis of Homo floresiensis are: Richard A. Kerr, Breakthrough of the Year: The Winner, Science 306 (2004): 201012; The News Staff, Breakthrough of the Year: The Runners-Up, Science 306 (2004): 201317; P. Brown et al., A New Small-Bodied Hominin from the Late Pleistocene of Flores, Indonesia, Nature 431 (2004): 105561; M. J. Morwood et al., Archaeology and Age of a New Hominin from Flores in Eastern Indonesia, Nature 431 (2004): 108791; Michael Balter, Skeptics Question Whether Flores Hominid Is a New Species, Science 306 (2004): 1116; and Ann Gibbons, New Species of Small Human Found in Indonesia, Science 306 (2004): 789.
- Some of Gould’s key writings on these issues include: Stephen Jay Gould and Niles Eldredge, Punctuated Equilibria: The Tempo and Mode of Evolution Reconsidered, Paleobiology 3 (1977): 11551; S. J. Gould and Richard C. Lewontin, The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme, Proceedings of the Royal Society of London B 205 (1979): 58198; S. J. Gould, Wonderful Life (New York: Norton, 1989); S. J. Gould, Full House (New York: Three Rivers Press, 1996); and S. J. Gould, Bushes and Ladders in Human Evolution, in Ever Since Darwin (New York: Norton, 1977), 5662.
- See C. C. Swisher III et al., Latest Home Erectus of Java: Potential Contemporaneity with Homo Sapiens in Southeast Asia, Science 274 (1996): 187074; and S. J. Gould, Our Unusual Unity, in Leonardo’s Mountain of Clams and the Diet of Worms (New York: Three Rivers Press, 1998), 197212.
- Jared Diamond, The Astonishing Micropygmies, Science 306 (2004): 204748.
- The quote is from Marta Mirazón Lahr and Robert Foley, Human Evolution Writ Small, Nature 431 (2004): 104344. For discussions of the multiregionalist and out of Africa views see Milford Wolpoff and Rachel Caspari, Race and Human Evolution: A Fatal Attraction (New York: Simon & Schuster, 1997); Christopher Stringer and Robin McKie, African Exodus: The Origins of Modern Humanity (New York: Owl Books, 1998); and S. J. Gould, Human Equality Is a Contingent Fact of History, in The Flamingo’s Smile (New York: Norton, 1985), 18598. For a discussion of polygenism and various versions of scientific racism, see S. J. Gould, The Mismeasure of Man (New York: Norton, 1981).
- Gould, Our Unusual Unity, 212. Also see Gould, Human Equality Is a Contingent Fact of History.