|One kind of diversity|
One of the reasons for biodiversity’s appeal is that it distills common sense: “Don’t put all your eggs in one basket.” Many baskets, more chances. “Hedge your bets.” That is, the idea behind biodiversity, the comparative advantage of many different investments, so to speak, rather than one single large investment, aids in successful adaptation and resilience against misfortune, whether, for example, in farming (mixed farming as opposed to monoculture) or in buying lottery tickets. The commonsense advantages of diversifying have been known for centuries, if not millennia.
Another reason for biodiversity’s appeal is less obvious but no less powerful: its congruence with a very old and pervasive worldview in Euro-American thought, the great chain of being, turning on the twin concepts of plenitude (fullness, plenty) and continuity. Plentitude and continuity are at the heart of that metaphor which intellectual historian Arthur Lovejoy traced nearly a century ago in the William James Lectures at Harvard: “The result was the plan and structure of the world which, through the Middle Ages and down to the late 18th century, many philosophers, most men of science, and, indeed, most educated men, were to accept without question—the conception of the universe as a Great Chain of Being, composed by an immense . . . number of links ranging in hierarchical order from the meagerest kind of existents, which barely escape non-existence, through every possible grade . . . up to the highest possible creature. . . “
This worldview centered in a hierarchical chain of creation, with its roots in Plato, Aristotle, and particularly in Neoplatonism, bears an obvious resemblance to the “hierarchy of variation” in contemporary ecological thought, not only in terms of plenitude, continuity, and hierarchy, but also in its bias toward holism. Of course, the chain of being is also notably different from biodiversity in the sense that sitting atop the chain was the Creator. Nevertheless, the resemblance is so striking as to suggest an important reason for the rapid and general acceptance of biodiversity; if biodiversity somehow “seems right,” it is in part because of the residue of this once most powerful worldview.
Are we dealing with mere resemblances, or was there a period in the history of Euro-American ideas when the great chain turned into biodiversity; and if the latter, how did that occur? Of course, certain underlying assumptions about the universe, that it is patterned and rational, as well as that its laws are humanly discoverable, helped. But I would suggest that as the great chain began to lose force in the late Enlightenment and early Romantic eras, it was gradually replaced by the ideas of diversity and the balance of nature; and that biodiversity was coined much later on to foreground the already-understood idea of biological diversity.
We have already encountered ideas of “Nature’s economy” and balance in many earlier blog entries; suffice it to say here that Gilbert White was marveling, in his letters from Selborne in the 1770s, over plenitude and balance in nature—balance conceived not so much as equilibrium but as economy, of Nature taking care of its own. In other words, for White, Nature’s economy was an expression of the great chain, just as it was for natural historians such as Linnaeus. Although for White, a cleric, God was at the head of the chain, a Creator is not a requirement for the concept. Natural theology in the early 19th century was an attempt to reconcile those incongruities. Darwin himself wrestled with that problem, of course, as did many scientists in the mid-19th century. Notable among them in the US were Louis Agassiz (who would not abandon the idea of God at the head and separate creations to explain the variety in nature) and Asa Gray (who eventually came around to the more secular view). Even the naturalist Thoreau embraced Darwin’s idea of evolution. Upon examination, Darwin’s idea of evolution retains the concepts of plenitude and continuity.
What about diversity? Again, Lovejoy is helpful. He broadly characterizes the Enlightenment as a period in Euro-American intellectual history when classic ideals prevailed, “controlled by the assumption that, in each phase of his activity, man should conform as nearly as possible to a standard conceived as universal, uncomplicated, immutable, uniform for every rational being." The single classic ideal began to be displaced, in the late eighteenth century, by diversity. Again, Lovejoy: “It came to be believed not only that in many, or in all, phases of human life there are diverse excellences, but that diversity itself is of the essence of excellence; and that in art, in particular, the objective is neither the attainment of some single ideal perfection of form in a small number of fixed genres nor the gratification of that least common denominator of aesthetic susceptibility which is shared by all mankind and all ages, but rather the fullest possible expression of the abundance of differentness that there is, actually and potentially, in nature and human nature, and – for the function of the artist in relation to his public – the invocation of capacities for understanding, sympathy, enjoyment, which are as yet latent in most men, and perhaps never capable of universalization. And these assumptions, though assuredly not the only important, are one of the common, factors in a number of otherwise diverse tendencies which, by one or another critic or historian, have been termed ‘Romantic’. . .”
Lovejoy is writing here chiefly in reference to art, not science; but we must remember that the divisions between the two were not so great in the eighteenth century as they are today. In short, although biodiversity and the acoustic niche hypothesis are current, they are an expression of very old and pervasive ideas about nature in Euro-American intellectual history, plenitude and continuity; and on such a foundation do they rest—a foundation that is under a twin challenge. One challenge comes from ecologists, who no longer believe in Nature’s economy or a balance of nature, but who nevertheless retain a belief in interdependence and biodiversity. Are those beliefs incompatible? And a second challenge comes from those deconstructionists who hold that the Romantic idea of nature is only that—an idea, and that it must be abandoned if we are to achieve a postmodern ecology worth wanting. We shall see.
1. "Biodiversity," in Stanford Encyclopedia of Philosophy, at http://plato.stanford.edu/entries/biodiversity/
3. Arthur O. Lovejoy, The Great Chain of Being (Harvard University Press, 1964 ), p. 59.
4. Ibid., p. 292.
5. Ibid., p. 293.
Photograph: Crowd listening at a festival, 2010, Bangor, Maine. Photo by Jeff Todd Titon.