I will agree that the name change was brought to a head by the discovery of some other objects that were either going to increase the number of planets or decrease them. According to Wikipedia, we have known Pluto's size since at least 1978 when its moon Charon was discovered. Wikipedia also notes that, up until the recent vote, there was no official definition of a planet. So the current vote involved no "re-definition" of the concept of a planet. I would say they were a few hundred years late on that one and, to be generous, at least 28 years late. The definition they recently devised included some fairly ambiguous concepts like "clearing your neighborhood" which, as was pointed out in Wikipedia, hasn't been completed by Neptune or Pluto wouldn't be there. Earth also still has some cleaning up to do. As a teachable moment, I also think that it would be good to point out to students that most issues in science are not decided by a vote. So I'm not a postmodern thinker but it seems to me that this controversy was all about definitions and the vote could have just as logically gone in one direction as another (regardless of any sentiment). Unless you reify the concept of a planet as a Platonic ideal, there is no right answer to what a planet is (although majority rules). It is operationally defined for the purpose of communication in science. I don't believe that anyone who voted against the new definition had any doubt about the size of Pluto or the discovery of Xena and other similar bodies. In fact, the vote could go differently next time the group meets with no change in the empirical evidence. Is there some real asymptotic limit on the number of things we call planets in the solar system? Will there be a problem if we identify a solar system with more than 10 planets by the current defintion (of course, the current definition only applies to our solar system)? It reminds me much more of some of the more inexact aspects of science such as deciding on a particular solution in factor analysis. One is not right and the other wrong but one might be more helpful as an explanatory construct. As a teacher of Research Methods, I will use this as a good example of the importance (and flexibility) of operational definitions in science but not as an example of how accumulating empirical evidence causes an increase in knowledge or a change in support for particular theories. For that, I will refer to how accumulating evidence caused the writers of the DSM to re-define Multiple Personalities as Dissocative Identity Disorder. Rick Dr. Rick Froman Psychology Department Box 3055 John Brown University Siloam Springs, AR 72761 (479) 524-7295 [EMAIL PROTECTED] "Pete, it's a fool that looks for logic in the chambers of the human heart" - Ulysses Everett McGill
________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Sat 8/26/2006 10:11 PM To: Teaching in the Psychological Sciences (TIPS) Subject: [tips] RE: Pluto's chromosomes On 26 Aug 2006 at 9:20, Rick Froman wrote: >> > 1) If the known size of Pluto fluctuated over the years and that is > actually what caused it to be removed from classification as a planet, > it is a pretty big coincidence that they realized how small it > actually > was on the same day that the definition of a planet was revised to > remove Pluto from consideration. No coincidence. The meeting was called because the weight of new discoveries, in particular the recent discovery of Xena, made it impossible to ignore the problem of Pluto. They didn't realize how small it was on the same day. The shrinking Pluto problem (not fluctuating Pluto) dates back many years. But I believe it was the discovery of Xena that made some sort of immediate decision imperative. Its discovery meant that the old imprecise understanding of what a planet was had to be revised. If all animals had four legs, and all humans had two, then defining the difference is easy. But what do you do when you then discover a stork? You have to refine your definition. The decision to boot Pluto was most definitely data-driven. Over the years they acquired much new data about the kinds of rocks out there. That data made Pluto's status unclear. They could re-define a planet to include Pluto, but then be required to also admit to the club many other Pluto-like objects since discovered, or they could boot Pluto. They chose the latter, and sentiment be damned. That admirable source Wikipedia tends to support my version. Check it out. So all your base is still belong to me. Stephen ----------------------------------------------------------------- Stephen L. Black, Ph.D. Department of Psychology Bishop's University e-mail: [EMAIL PROTECTED] 2600 College St. Sherbrooke QC J1M 0C8 Canada Dept web page at http://www.ubishops.ca/ccc/div/soc/psy TIPS discussion list for psychology teachers at http://faculty.frostburg.edu/psyc/southerly/tips/index.htm ----------------------------------------------------------------------- --- To make changes to your subscription go to: http://acsun.frostburg.edu/cgi-bin/lyris.pl?enter=tips&text_mode=0&lang=english <http://acsun.frostburg.edu/cgi-bin/lyris.pl?enter=tips&text_mode=0<=english>
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