7.1 Something Incredibly Exciting Happened

Is Pluto a planet? The “official” answer, of course, is no, but if you were born before August 2006, it was a planet when you were a child, so what happened? A writer on Pinterest posted “If someone 50 years ago were told that there would one day only be eight planets, they would think something incredibly exciting happened.”

Pluto didn’t explode or leave its orbit, but something did happen: the International Astronomical Union (IAU) reclassified Pluto because it did not meet their requirements for being defined as a planet. That decision might not qualify as “incredibly exciting,” but it certainly caused a stir. The IAU, for example, received many letters from children, including a young girl who tried to convince them to change its status back, writing “Do people live on Pluto? If there are people who live there, then they won’t exist. Some people like Pluto. If it doesn’t exist then they don’t have a favorite planet.”

Two years later, many astronomers gathered at Johns Hopkins University for “The Great Planet Debate,” but they couldn’t reach a consensus, so the IAU standard ruled the day and textbooks everywhere were changed. In other words, some scientists argued for changing Pluto’s status, others argued against the change, and the first group won.

• In a similar vein, you could pose many questions about why American society is the way it is, such as:
• Why does the U.S. have a president, not a king?
• Why is there a drinking age, instead of letting children of any age have alcohol?
• Why do movies get an R-rating if they contain scenes of smoking?
• Why does the Upper Peninsula belong to Michigan instead of Wisconsin?
• Why do you need a license to drive a motorcycle but not an electric bicycle?
• Why is New Year’s Day a national holiday?

(Similar questions could be raised about any country on earth)

One answer to all of these questions is: because someone argued successfully that things should be that way, and the people who argued against them were unsuccessful. To a large degree, the world is the way it is because of who won arguments and who lost. How do you win an argument? As the previous chapter showed, there can be many factors involved, but this chapter will explore logic and reasoning: formulating arguments that “make sense” to an audience.