Rusted, but still strong

Of all the concepts of nature I have so far encountered in my research on the history of evolution as an idea, few (if any) are as virulent as the Great Chain of Being. Although Stephen Jay Gould claimed that White's 1799 book An Account of the Regular Gradation in Man, and in Different Animals and Vegetables represents the last gasp of the Great Chain of Being the idea was not simply discarded or forgotten. While the concept ultimately failed to make sense in terms of the ordering of nature it found a refuge in evolutionary theory, particularly in considerations of how humans are related to apes.

As I have written elsewhere the connection between apes and humans has been recognized for hundreds of years, apes like chimpanzees seemingly being intermediates in the Chain that linked humans to "lower" primates. Combined with racism, this program caused researchers like White to try and make some populations of people more ape-like and some apes more human like, pulling at both ends of the supposed sequence to try and close the gap. It would be comforting to think that White's book represented the last vestige of this type of thinking but actually doing so would be naive. Even though the fossil evidence for the great age of our species was recognized in 1859 there were no fossil transitional forms to link humans and apes together. Whatever case was to be made for the evolution of humans from apes would have to be based upon creatures then living, and this gave the Chain a new place to hide.

Although I am not calling Darwin a rabid racist or suggesting that natural selection is a racist theory (see here for rebuttals to these common misconceptions) the lowering in status of some humans and the elevation of some primates did appear in his writing. With no fossil ancestors to close the gap between man and ape Darwin would had to rely on living primates to explain how humans may have evolved, and in the conclusion of The Descent of Man he uses baboons and the native peoples he saw during his journey to South America to help close the gap;

The main conclusion arrived at in this work, namely that man is descended from some lowly organised form, will, I regret to think, be highly distasteful to many. But there can hardly be a doubt that we are descended from barbarians. The astonishment which I felt on first seeing a party of Fuegians on a wild and broken shore will never be forgotten by me, for the reflection at once rushed into my mind - such were our ancestors. These men were absolutely naked and bedaubed with paint, their long hair was tangled, their mouths frothed with excitement, and their expression was wild, startled, and distrustful. They possessed hardly any arts, and like wild animals lived on what they could catch; they had no government, and were merciless to every one not of their own small tribe. He who has seen a savage in his native land will not feel much shame, if forced to acknowledge that the blood of some more humble creature flows in his veins. For my own part I would as soon be descended from that heroic little monkey, who braved his dreaded enemy in order to save the life of his keeper, or from that old baboon, who descending from the mountains, carried away in triumph his young comrade from a crowd of astonished dogs - as from a savage who delights to torture his enemies, offers up bloody sacrifices, practises infanticide without remorse, treats his wives like slaves, knows no decency, and is haunted by the grossest superstitions.

While not as nauseating as some of White's earlier attempts to span the divide between humans and apes Darwin's aim was similar. Even though our actual ancestors were missing their archetype still existed among "savage" people, and the virtues of monkeys and apes helped provide a platform by which they could jump and touch humanity. Although controversial, the discovery of "Java Man" (known as Homo erectus to you and me) finally gave naturalists a transitional human worth arguing over and the emergence of paleoanthropology (and its split from cultural anthropology) soon overshadowed comparisons between living humans and apes. (Indeed, while studies of primate behavior continued they were somewhat relegated to a side-branch, existing within ethology but not as close to evolutionary science. It has only been more recently that primatology has made a comeback, but there can be little doubt that studies of living primates are vital to understanding our own evolution.)

The presence of the Chain in The Descent of Man is relatively subtle; in other works it was much more blatant. In the 1875 work The Pre-Adamite, or Who Tempted Eve? A. Hoyle Lester attempts to reconcile Genesis with a vague idea of evolution by invoking a Chain-like series of events, each successive step coming closer to humans. After several paragraphs of purple prose worthy of Omphalos, Lester writes;

In the ascending series of the creative programme comes the monkey, or the lower grade of the quadrumana tribes, and in due course of formation we have the baboon and the orang-outang, who occupy their periods in the creative designs of the Great I Am, until finally the gorilla, the highest standard of the quadrumana race, takes his position among created animals, and forms the uniting link between the brute creation and the lowest standard of the human family.

Who were the "lowest standard[s] of the human family"? Not one to break with racist tradition, Lester says that Africans were first as they were best suited to a hotter planet that lighter-skinned races would find intolerable. Next came the Malayan people, American Indians, and Chinese in sequence, the author claiming a unique and distinct origin "in no way connected with any former creation" for each. Adam and Eve, then, were the very first caucasian people, sharing no common ancestor with the rest of humanity. Lester is so offended by the idea of a common origin for all humans that he penned one of those infamous statements at which one does not know whether to laugh or cry;

... it answers our purpose to recognize only five races, as this subdivision has already been made, and is sanctioned by ethnologists of our age. They have, however, almost universally been traced back to the same ancestor, under the belief of unity of the races, which theory attaches itself like an incubus to the fair Caucasian, and brings a blush to the cheek of intelligent beauty. I would wipe this stain from our escutcheon, and set at right the inquiring mind, as regards the error in question.

Although some attempted to find morphological characters to divide humanity, language and perceived levels of intelligence played a much more prominent role in organizing the scale of human development. Racist rankings and associated research provided some with a sequence of human evolution from savage to refined, and the question of whether or not primates had language attacked the problem from the other direction. If monkeys or apes could be shown to have language, especially if that language was similar to that of "lower" grades of people, then an evolutionary sequence of types could be established to show how the human mind had evolved. In this case the idea of the Chain persisted, the linkage of evolution by natural selection with progress leading some to try and create an ascending sequence of complexity. Even though Darwin had illustrated evolution as a branching process the need to find gradations between forms easily lent itself to straight-line thinking.

Perhaps the problem with the Chain is that it has created so many well-known icons. If we could view the evolutionary tree (or bush, if you prefer) as it really is we would be greeted with a messy tangle of branches that would be difficult to decipher. Putting things on a straight line simplifies matters, the fact that evolution occurs becoming clear. Illustrations of horse evolution from small, four-toed browsers to large, one-toed grazers and the "March of Progress" are both well-known examples of this and are exceedingly difficult to dislodge; even though we know that both are wrong they have shown an impressive (if irritating) amount of staying power. (The utility of the straight-line concept in satire has only helped entrench the idea that evolution is strictly linear. Cartoons of the "devolution" of humans are commonplace and will probably be with us for quite some time.)

Will we ever be rid of straight-line iconography in which superior-inferior ranks are inherent? I have my doubts. Even though cladograms have made their way into popular books about evolution many of them still show a horizontal, straight-line progression in the canopy of the trees. Those already familiar with cladistics might look at the trees and be able to decipher what the relationships mean, but for those unfamiliar with nodes and sister groups it sometimes looks like new packaging for an old idea (I am specifically thinking of the phylogenetic tree of whales that first appeared in At the Water's Edge, although in this case the "march" is vertical). We may very well know that evolution is a branching process but the icons we continue to produce still suggests otherwise; we are still linked to the Chain.