Sunday, November 18, 2012

Naming Nature by Carol Kaesuk Yoon

Published by W. W. Norton & Company
For a book that aims at a large readership, Naming Nature (2009) dares to explore a topic that seems anything but sexy at first sight: taxonomy. But we know better and we won’t turn away from the book, since the act of naming and classifying organisms is of course a very exciting activity! (No, I’m not kidding.)

In her book, Carol Yoon recapitulates the history of the discipline and presents the main scientific actors who contributed to the advance of taxonomy. She thus tells us about important figures:  Linné (Carolus Linnaeus), who is considered the founder of modern taxonomy, and who notably popularized the use of the binomial nomenclature (Felis catus and Escherichia coli, to name two lovable examples); Charles Darwin, who needs no introduction, and who revolutionized taxonomy by showing that species were not immutable; Ernst Mayr,  one of the main architects of the modern synthesis of evolutionary theory; Linus Pauling, the Nobel laureate chemist who had the brilliant idea of classifying organisms by looking at the amino acid sequence of hemoglobin; and Carl Woese, microbiologists’ modern hero, who classified organisms by looking at their DNA sequence and turned the tree of life topsy-turvy. Nothing new to me here, but, after all, this book is not written for biologists.

On the other hand, I learned facts that I was ignorant of (and this seems to be an inexhaustible category of facts...). For instance, I learned that it was Julian Huxley (member of a family in which each member is either a literary or a scientific genius) who coined the term ‘systematics’ and proposed to use it in place of taxonomy.

I also learned about scientists that were unknown to me. First, Robert Sokal and Peter Sneath, who were pioneers in numerical taxonomy, the method which consists in computing many phenotypic characters to infer the organization of living organisms by mathematical means; interestingly, Sokal and Sneath developed the method independently but decided to join forces, and together they wrote a textbook: Principles of Numerical Taxonomy. Sokal, an entomologist, invented one of the most widely used mathematical method for clustering in phylogeny: UPGMA (Unweighted Pair Group Method with Arithmetic Mean). As to Sneath, he was a microbiologist who worked with Chromobacterium violaceum, and later became much involved in the leading reference textbook Bergey’s Manual of Bacterial Systematics.

Yoon does a great job at describing the fight that occurred during the sixties between the young numerical taxonomists and the rearguard action of the evolutionary taxonomists, led by Ernst Mayr and George Gaylord Simpson. She further explains how the taxonomic method of cladistics, propounded by Willi Hennig, finally took over numerical and evolutionary taxonomy and became the consensus scientific view. 

Carol Yoon’s book, however, is much more than a mere historical account of taxonomy. The angle of Naming Nature is to explore the tug-of-war that took place between taxonomy and evolutionary theory, and it is purposely subtitled The clash between instinct and science. Yoon’s take on this is that taxonomy was originally guided by an instinctive understanding of nature and living organisms. She refers to this instinctive vision as the ‘umwelt’ (from the German word for ‘environment’), a term used by some biologists to signify the world perceived by a given species. (I’m no big fan of the import of German and French terms in the English language, and in my opinion Yoon would have done as well by keeping the word 'instinct'. Well, I guess it’s just the zeitgeist.) 

According to Yoon, it is thanks to our umwelt that humans order the living organisms in a certain way, such as all fishes together and all birds together. It is because of our instinct that folk taxonomies resemble each other over and over again. This innate perception of the living world, says Yoon, is deeply embedded in our brain, and as an evidence for this she tells the story of patients who, after specific brain injury, lost the faculty to recognize living things while retaining their capacity to discriminate inanimate objects. I was quite surprised to learn that we have a specific brain area dedicated to the living world, because I  know of the human tendency to attribute will to non-living things, such as wind, water, rocks, and so on (what probably gave birth to animism). 

The expression of our 'umwelt' starts at an early age and can be seen in the children’s love of classifying things. But because many kids live in urban areas, thus remote from the natural fauna, they may focus on unlikely sets of creatures, such as dinosaurs or—this is a funny and telling example—Pokémons! Think about it: a child can really become an expert in the taxonomy of Pokémons… In Yoon’s view, Nintendo simply co-opted the children’s instinct to build a succesful product. Such move, however, is not limited to children, and Yoon suggests that most branded products are now occupying brain space that once was dedicated to the living world. (Interestingly, this echoes what Desmond Morris wrote in the sixties about super stimuli in our modern environment: each commercial product tries to capture our attention through shape, pattern, colour and so forth.)

But the hijacking of our instinct by commercial brands is not, though, the main message in Naming Nature. The central idea is that there is a clash between instinct and science, between our umwelt and modern taxonomy. For instance, Yoon's favorite example is that cladistics tells us that there is no such group as the ‘fish’. What we instinctively call ‘fish’ is in fact made of various groups with distinct evolutionary histories. What are we to do with that? Carol Yoon writes, p. 268:

“[…] science has slowly but surely distanced itself from the view of the living world that all humans share and understand. It began back in Linnaeus’s day, as science took for its focus the newly gigantic living world, a diversity of life so vast that the umwelt could hardly manage to wrap its anciently evolved brain around it, so unlike our ancestors’ world had it become. Then along came Darwin with his revelation of evolution and a vision of an evolving world that looked nothing like what we seemed to see before us. The evolutionary taxonomists did their best to pretend all was well, but to no avail. The numerical taxonomists, the molecular biologists, and the cladists each took their turn at pushing the umwelt further and further aside, battling until that vision of the living world was thoroughly discredited. No wonder, then, that we have become so blind to the living world—continually failing not only to notice its beauty but its very existence—and so thoroughly disinterested in its disappearance.”

I have several difficulties with this idea. First, on many occasions science proves to be totally counter-intuitive to human experience (a worn-out example is the Einsteinian idea of space-time), so the evolution of taxonomy is not a unique case study, but rather a common consequence of the conduct of science. Secondly, even though I don’t want to minimize the impact of scientific ideas on  human thought, I really doubt that the layman cares about the controversies between taxonomy schools (in the same sense that nobody really cares about space-time during day-to-day life). I don’t believe that the scientific views on taxonomy have significantly modified the way we interact with the living world—I would be more prompt to point at the urbanization of society as a cause for our modern ‘blindness’ to our fellow creatures.

Carol Yoon is a fine writer, even though I sometimes felt that style won over substance. And since I recently wrote about science books' length, I think this one may have benefited from a few cuts.  But, and despite my disagreement with Yoon's central idea, I think the book is really worth reading. Maybe I liked it precisely because Naming Nature promotes a personal idea. One can agree with it or not, but the fun is in thinking about the idea. The endorsement of it is secondary.



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