These may ye eat of all that are in the waters: whatsoever hath fins and scales in the waters, in the seas, and in the rivers, that may ye eat. And all that have not fins and scales in the seas, and in the rivers, of all that move in the waters, and of all the living creatures that are in the waters, they are an abomination unto you…

The folk etymology of the word "barbarous" — non-Greek speakers, whose languages sounded like "barbarbar" to the Greeks — suggests one of the problems with early classifications. For the Greeks, separating the world into those who spoke Greek and those who didn’t (and then further refining it: non-Greeks versus Greeks, and then Greeks from particular regions of Greece) was a natural one (for the ancient Greeks, at least), but it doesn’t work very well for other classifications. How do you classify, say, a rat? Is it a Greek-speaking rat? Perhaps a Greek-speaking rat from Egypt?

Man is a classifying animal. The urge to break things down into their component parts is an ancient and honorable one. Witness, for instance, the dietary laws delivered by God to Moses and Aaron in Leviticus:

These may ye eat of all that are in the waters: whatsoever hath fins and scales in the waters, in the seas, and in the rivers, that may ye eat. And all that have not fins and scales in the seas, and in the rivers, of all that move in the waters, and of all the living creatures that are in the waters, they are an abomination unto you…

The folk etymology of the word "barbarous" — non-Greek speakers, whose languages sounded like "barbarbar" to the Greeks — suggests one of the problems with early classifications. For the Greeks, separating the world into those who spoke Greek and those who didn’t (and then further refining it: non-Greeks versus Greeks, and then Greeks from particular regions of Greece) was a natural one (for the ancient Greeks, at least), but it doesn’t work very well for other classifications. How do you classify, say, a rat? Is it a Greek-speaking rat? Perhaps a Greek-speaking rat from Egypt? A number of methods of classifying animals (zoa, hence zoology) were invented throughout the centuries, with Pliny the Elder‘s The History of Nature being probably the most influential (the complete Latin text is available, not that it does me any good) being perhaps the most important. After the discovery of the New World, Europeans needed a way to start classifying American animals. Were they the same as European animals? Some local variant? New species entirely? Eighteenth century Swedish botanist Carolus Linnaeus (that is, Karl von Linné) hit upon the method that’s still in use today. Building upon the work of John Ray, Linneaus — a meticulous notetaker, whose botanical gardens have been reconstructed from his notes — devised a hierarchy of classifications (kingdoms, phyla and the like), as well as a system of binomial classification (Gorilla gorilla, Homo sapiens). Linneaus’ actual classifications (especially for plants) were largely discarded, but the taxonomy he created survives (with modifications) today.

That’s all well and good for animals — you can find out if two birds or cats or fish can produce viable offspring, which before the discovery of DNA was a key indicator of specification. But how do you classify ideas? A recent article in The Atlantic makes the case — which I had never really considered — that Roget’s Thesaurus was intended not as a guide for choosing le mot juste but as a taxonomy of human thought. Coming up with such a thing is damn hard. Witness the efforts of American Library Association cofounder Melvil Dewey, whose Dewey decimal system. (Melvil Dewey is, as far as I can tell, no relation to the American philosopher and education theorist John Dewey, after whom I always thought the Dewey decimal system was named.) The Dewey decimal system is overly imprecise and the Library of Congress classification is utterly impenetrable to the layperson. But there’s got to be a better solution — with the huge amount of data being pumped onto the Internet, there has to be some cunning method of classifying it all, right?

Although I will probably never make it to library school, when I think about issues like these, I kind of want to. Jessamyn’s librarian.net is mostly focused on the day-to-day activities of working librarians, but I can live life vicariously through the many information architechts who have weblogs or through Nanette, a Chicago indie kid who has just started library school. Go forth and classify!