This week the International Astronomical Union downgraded Pluto from planet to dwarf planet. Discovered in 1930 and named after the Roman god of the underworld because it was so far from the sun, Pluto quickly became the ninth planet in the solar system because it was initially thought to be larger than the earth. Pluto's planetary status came into question not long after, when it became clear that the new object was actually smaller than the earth's moon. A move in 1999 to reclassify Pluto was abandoned after schoolchildren mounted a letter-writing campaign to save the lonely planet from ignominy. But the discovery three years ago of 2003 UB 313, known to her friends as Xena, an object in solar orbit that is both bigger than Pluto and farther from the sun, sealed Pluto's fate.
The IAU's move will do more than sadden American schoolchildren. It also has economic repercussions, triggering the revision of everything from astronomy texts, dictionaries, and almanacs to planetarium programs, place mats and solar system mobiles. The online encyclopedia Wikipedia was the first reference work to note the change in Pluto's definition, though few astronomers turn to Wikipedia when they need to look something up. Ninth planet t-shirts immediately went on sale on Craig's List, an indication that even dwarf planets may have a silver lining for the entrepreneurially-minded.
But what's most interesting to me from a linguistic perspective is the act of redefinition, the fancy bit of linguistic prestidigitation that has just occurred before our very eyes.
According to new IAU guidelines, planets must now meet three criteria: they must orbit the sun; they must be large enough for gravity to pull them into a spherical shape; and they must be able to sweep other objects out of their path as they move through space. Pluto, though big enough and round enough, was just not good enough to meet this last criterion.
Those who believe that Pluto should remain a planet have had a nasty shock. In a reversal of the situation that Galileo found himself in, publicly renouncing his heliocentric heresy, while privately believing that the earth moved, they will secretly cling to their now-unscientific view of the universe. Evolution may be just a theory, they will insist, but you can see planets -- though you can see some of them only with a very large telescope.
But renaming Pluto may prove a bigger shock to those who believe that language must be a fixed and stable entity, a rock to cling to in parlous times, a shibboleth to separate friend from foe, a dependable beacon by which to judge right from wrong.
But language is not a pole star, not, as Shakespeare might have put it, "an ever-fixed mark. . . that is the star to every wandering bark." While language is systematic, it is never altogether stable. Its sounds, its sentences, its meanings are constantly shifting orbit, changing and adapting as we move from context to context, from mood to mood, from certainty to puzzlement.
Many of the definitions I learned in school have changed: the number of U.S. states, the number of human chromosomes, the number of Jupiter's moons. The map of Africa that I memorized in seventh grade is no more. "Red" China, the subject of many an emotional high school debate, joined the United Nations after all. The mighty Soviet Union came apart. And like Galileo's earth, the Brooklyn Dodgers moved.
OK, you say, these are "official" names subject to "official" redefinition, not to mention the vagaries of history, geography, and politics. No surprise there, since officials, whether they're astronomers or soccer refs, have been known to change their minds. But there are still seven continents and seven seas, right? Not in France, which only recognizes five of each. A French teacher once showed me on a globe that North and South America must be one continent, because they're connected. And Australia, he insisted, was an island near what I erroneously called the Indian Ocean, really just an arm of the Pacific, as is the Arctic Ocean, if I remember correctly. Evidemment. Or as we say in English, QED.
English doesn't have to agree with French, to be sure. But in many cases English doesn't even have to agree with itself all the time. It was Emerson who said that a foolish consistency was the hobgoblin of little minds. That's why a word like 'literally' can mean figuratively, not literally; a double negative can signal a negative, not a positive; 'between' can refer to more than two, or just two; and commas may or may not be used to separate a series of three (though obviously that honor sometimes falls to semicolons).
Looked at that way, renaming Pluto as a dwarf planet is no big deal. At least Pluto wasn't reclassified as a planetary object, a category now reserved for celestial bodies even less important than the planet formerly known as 9. And Walt Disney has no intention of getting rid of its cartoon character Pluto, introduced as Mickey Mouse's pet dog in 1930 right after the discovery of the dwarf plant. The IAU's action is just a drop in the semantic bucket, of no more significance in the grand scheme of things linguistic than the fact that the inhabitants of Pluto don't call our planet earth.