Editorial: What's in a name?

by Geoff Hart

Previously published as: Hart, G. 2007. Editorial: What's in a name? the Exchange 14(1):2, 8–9.

"That which we call a rose / By any other name would smell as sweet."

—William Shakespeare, Romeo and Juliet

Amateur astronomers and other fans of heavenly bodies received something of a shock this past year when the International Astronomical Union (IAU) suddenly announced that Pluto was no longer a planet. The planetary status of Pluto, whose existence was first confirmed by Clyde Tombaugh in 1930, died a premature death at the relatively young age of only 76 years.

I was one of those who mourned—and still mourn—its passing. But being of a philosophical bent (some might say only "being somewhat bent"), I always try to make lemonade when life hands me lemons, and as editor of this newsletter, it seemed appropriate to see what fruit juice might be made from my disappointment. Since there's plenty of empty space to be filled in each issue (hint, hint), an editorial on the meaning and use of names seemed appropriate.

For a detailed and enlightening discussion of the factors that went into the IAU's decision to deplanetify Pluto, I recommend Steven Soter's article, What is a planet?, in the January 2007 issue of Scientific American. For those with less patience, a brief summary: The traditional definition of "planet", and the one most familiar to non-astronomers, focused on the concept of an arbitrarily large celestial object with a stable orbit around its primary (in our case, the Sun); although some planets might have moons, others did not, so the possession of a moon was thus not a criterion for planethood. So far, so good. Unfortunately, the relentless increase of astronomical knowledge had gradually made such a definition untenable. How could Pluto be considered a planet when several moons in our solar system (e.g., Jupiter's Io, Ganymede, and Callisto) were larger? If Pluto remained a planet, then what should we say of Eris (briefly and charmingly named Xena, after Lucy Lawless' beloved warrior princess) and the hypothesized dozens of similarly large planets? The solution was either to start forcing schoolchildren to memorize an ever-increasing list of planets, or to come up with a more effective definition of planet. Soter describes the new criteria proposed by IAU, and the flaws in these criteria, thoroughly and convincingly, so if this topic interests you, I encourage you to read his article.

When I first heard of the IAU's decision, my immediate reaction was that astronomers were engaging in that reflexive form of binary thinking (attempting to classify everything in the world into neat, non-overlapping categories) that I criticized in my editorial in the September 2005 issue of the Exchange. However, in my attempt to be concise and emphasize the central point of that editorial, I neglected to point out that the process of binary thinking is of crucial importance in science. Our ability to separate information into discrete or semi-discrete categories is a powerful tool for determining how well we understand something. It also reveals much about how we think about that information.

Possibly more important still is the fact that as scientific communicators, we cannot explain something to anyone else until we understand it ourselves. Which leads us to the subject alluded to in the title of this essay: What's in a name? Like any other word, a name allows us to attach a label to a concept and the collection of related information. Once understood, that name then becomes the only useful kind of jargon—a word that lets us communicate concisely because everyone understands its meaning and because it communicates more efficiently than having to repeat the full description underlying the name every time we want to express that concept. Unfortunately, it's the "full description underlying that name" that causes problems. Sometimes our understanding of that description drifts out of synch with the expanding body of knowledge. When that happens, we have a problem.

The problem with the label planet was that it no longer adequately reflected our understanding of the complexity of how the solar system developed and no longer accommodated our understanding of the many structures (such as the Kuiper belt) that had not been imagined when the original definition first became common. When a name no longer accomplishes the purpose it originally served (efficient, concise encapsulation of a larger body of knowledge), then it's time to change that name. As Soter notes in the conclusion of his article:

"To be useful, a scientific definition should be derived from, and draw attention to, the structure of the natural world."

That is, the name must have more than mere historical importance: it must also have a practical purpose, and must serve that purpose well. (A great many names chosen by scientists fail this test. Perhaps that's a topic for a future editorial.)

This is an interesting and important conclusion, both because it reveals something of how scientists think and because it shows us how scientists can become lost in their own discourse and ignore the larger context in which that discourse occurs. Many of those who objected to the deplanetification of Pluto, myself included, were responding from a purely pragmatic, and not particularly scientific, perspective: everyone knew, and had known for more than 70 years, that Pluto was a planet, so why change this established fact? Others, including a surprisingly large number of astronomers (who presumably knew better but who responded from the heart anyways) objected to the seemingly arbitrary nature of the new classifications. But the "why" behind the IAU's decision was explained clearly and elegantly by Soter:

"We can revise our definitions when necessary to reflect the better understanding that arises from new discoveries. The debate on the definition of a planet will provide educators with a textbook example to show how scientific concepts are not graven in stone but continue to evolve."

The issue of naming has clear relevance to scientific communicators. To the extent that our communication is restricted to the discourse community of science, Soter's explanation of the new criteria fits well with my assertion that a name must communicate clearly and efficiently to those who will be dealing with that name as part of their professional work. But the strong negative reactions to Pluto's new status that have been expressed both by astronomers and the general public reveals a more important point for those of us who must also communicate outside the scientific community: a radical revision of any name used by the public requires equally radical efforts to explain and justify the change. Where the IAU failed was not in its decision—which was indeed arbitrary, albeit in a logical and useful way—but rather in how vague their initial definitions were and how poorly they communicated the reason for the new definitions to both their fellow astronomers and the general public.

This kind of confusion might have been eliminated, or at least mitigated, if more skillful communicators had been involved in the process of setting and communicating the new definition: those who framed the definition clearly understood what they were trying to achieve and the technical details that had led to the new classification, but like many an author (not just scientist authors), they failed to bridge the gap between their personal understanding and a new comprehension and acceptance by the audience they were attempting to persuade. Bridging that gap is where we come in, and it's the role I urge you to consider taking on in your own work as a scientific communicator.

My essays on scientific communication have now been collected in the following book:

Hart, G. 2011. Exchanges: 10 years of essays on scientific communication. Diaskeuasis Publishing, Pointe-Claire, Que. Printed version, 242 p.; eBook in PDF format, 327 p.