Friday, June 8, 2012

Naming Nature: The Clash Between Instinct and Science

Carol Kaesuk Yoon, a science writer for the New York Times, has done her level best, in Naming Nature, to make taxonomy interesting. The field has been shaken by several methodological “revolutions” in the last half-century, and as it turns out, these are fascinating in themselves. So much so, that readers may find themselves rehearsing the Shakespearean quip, “Methinks she doth protest too much.” Yes, taxonomy is interesting. On the other hand, Yoon’s attempts to popularize it and place it within a larger philosophical context suffer from a shaky grasp of the underpinnings of the “naming” process itself.

The habit of naming species goes back to the Stone Age, no doubt. Hunters knew which animals to pursue, gatherers knew which roots to unearth, shamans knew which herbs to boil. And they passed on this information from generation to generation by recourse to names. God presented Adam with the opportunity to name the creatures in the Garden of Eden, which suggests that the naming process has always been, to some degree, arbitrary, rather than divinely inspired.

Yet from the first, the distinctions established by Stone Age taxonomy were scientific, in so far as they were based on observable differences between types of things. But they were in no way systematic. It was not until the eighteenth century that the Swedish naturalist Karl Linnaeus developed the nomenclature still in wide use today, with two-part Latin names and a vast scheme of kingdoms, classes, orders, families, and species, in a cascading series of nested groups.

Yoon describes the development and significance of Linnaeus’s new system thoroughly; it’s the one we still use today. But like other systems before it, the family trees Linnaeus developed were often inaccurate, because species that look similar aren’t necessarily closely related.

The rise of Darwinian theory presented taxonomers with a new challenge: to develop a scheme that accurately reflected the chains of organic development through which various species evolved. In the course of the twentieth century, new techniques were developed to expose these relationships. Yoon describes how numerical taxonomy was developed in Lawrence, Kansas, by an obscure researcher named Robert Sokal, who, using bees as his subjects, coded a wide variety of characteristics on punch cards and then determined how closely the various types matched one another.

This is what taxonomists had always done. But in the past, it had been common practice the “weigh” characteristics that were deemed especially significant—a judgment that was based on nothing but intuition. Sokul stuck religiously to the data, and came up with a tree of relationships that different is several respects from the then-accepted pattern.

Then, in the late 1950s, chemists began to study proteins, amino acids, and other such stuff with a view to determining how closely various species were related. By working on a molecular level, these researchers were able to establish plausible relationships between species that could never have been compared before—humans, rabbits, kangaroos, turtles, snakes, and yeast. The fruits of these investigations often resulted in taxonomies very similar to those derived from more traditional methods, though they also produced a few whopping surprises.

The third “revolution” in taxonomy came about as the result of the publication, in 1950, of a book with the forbidding title Grundzüge einer Theorie der Phylogenetischen Systematik by a German fly specialist named Willi Hennig. In brief, his approach was to determine relationships between species by identifying similarities that were shared by them and no other groups.

Yoon spends a good deal of time explaining how this method works, and its’ time well spent. The more basic point is that Hennig, for the first time, “determined which characteristics mattered, which could be counted on to point a taxonomist in the right instead of the wrong direction.”

Hennig’s theories didn’t gain a significant following until twenty years later, but eventually, on the basis of the principles he espoused, the science of cladistics was born—a development that threw taxonomy into yet further controversy and disarray. Cladistics teaches us, for example, that mushrooms are animals and there is no such thing as a fish.

Yoon does a good job of bringing to life the often nerdy protagonists of this drama, and she loves to explore the arrogance, ridicule, and ego-bruising that peppers the tale, though such emotions almost inevitably accompany radical changes in any academic field, as accepted wisdom slowly gives way in the face of new evidence.

But Yoon also has a broader theme: that as taxonomy removed itself from the hands-on study of organisms toward statistic or molecular levels of inquiry, human societies also became gradually more removed from the natural world, so that nowadays very few people know much of anything about their natural surroundings.

Yoon anchors this theory by means of an obscure German concept, umwelt. The word itself is actually not so obscure. In German—so I’m told—it simply means “environment.” But Jakob von Uexküll made use of it to suggest that every animal species lives in a different world due to the fact that each species has a different capacity to sense things. Dogs are color blind but can detect an astonishing array of smells. Thus the world they inhabit “looks” very different from that of a human, who sees much but smells little, or a wood tick, who is sensitive only to body heat and the odor of butyric acid.

Yoon’s contention is that the human umwelt once encompassed a firm and detailed grasp of the natural world. In the course of time, she suggests, we have lost nearly all of our rapport with our natural surroundings. She refers nostalgically to the indigenous tribes of Mexico, who may know the names and uses of a hundred plants by the age of five.

All of this may well be true, though it’s a mistake to imagine the human umwelt must refer only of the natural world. The challenges humans face in their struggle for survival also include avoiding being run down in traffic, responding appropriately at job interviews, and knowing when to pull their retirement funds out out of the stock market.

And regardless of which elements figure prominently in the human umwelt, Yoon is stretching the reader’s credulity in suggesting that changes in the science of taxonomy have anything much to do with it. No doubt, the fact that urban folk no long have any real contact with plants or animals is a more significant factor. And yet this is precisely her thesis. This is precisely the link that holds these two elements of the book together.

Regarding the rise of numerical taxonomy, for example, she remarks, “There was nowhere left now for our unwelt to hide. Subjectivity and the sense and intuition of the order of life—all the gifts of the umwelt—were being viewed not only as problematic for the doing of science but just plain wrong.”

A few pages further she suggests there may be a connection between new taxonomic methods and a broader change in the way people relate to nature: “It wasn’t just scientists who were stepping away from luxuriating in the sights, smells, and sounds of the living world. The rest of us were, too.”

To borrow an expression from the American South, “This dog won’t hunt.” The human umwelt, such as it is, has never been based on a formal or scholarly taxonomic system, Linnaean or otherwise. Rather, it has always been based, in so far as it refers to the natural world, on what urban academics typically refer to as woodcraft and folklore. I would be surprised to find that even one in a hundred adults from Western Europe or America has heard of Karl Linnaeus, not to mention those academics—Hennig, Sokal, and the rest—who, in recent decades, have significantly modified his system. We can be pretty sure that the children of Tzeltal Mayan families who, even today, know the names of 200 plants, didn’t learn them from a book. Thus Yoon’s repeated, and eventually tiresome, lament for the withering of the human umwelt sits very uneasily within the often fascinating history of modern taxonomy.

At one point near the end of the book, Yoon writes, “With the triumph of science, what traces of the umwelt can still be seen today?” The answer must be: “Modern science is our umwelt.” And for the most part, it’s a good one. It’s a bit surprising to find how little respect this New York Times science writer has for it. Nor does such a scientific umwelt preclude the more intuitive understanding of our natural surroundings that Yoon seems to see slipping away. As different species have different umwelts, so may different individual humans. If you take a walk in the woods with Eliot Porter, Gary Snyder, and David Koch, you will be exposed to three rather different umvelts, I suspect.

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