Friday, January 13, 2006

Multiple working hypotheses and the common cold

One of the historical underpinnings of my field is the idea of multiple working hypotheses, as eloquently put forth by T.C. Chamberlin in 1890 in Science. Chamberlin was very concerned about "parental affection" influencing scientists' ability to objectively test (and maybe reject) a dominant hypothesis, because it became a sort of intellectual offspring. Instead he argued for the method of multiple working hypotheses:
"The effort is to bring up into view every rational explanation of new phenomena, and to develop every tenable hypothesis respecting their cause and history. The investigator thus becomes the parent of a family of hypotheses: and, by his parental relation to all, he is forbidden to fasten his affections unduly upon any one."
This idea is particularly important in the field sciences where the scientist is often making observations about what you might call a "natural experiment," which may have occurred at some point in the past. If you have but a single hypothesis it might be easy to find evidence than in your view validates the hypothesis (causes the effect). The example that Chamberlin uses is the origin of the Great Lakes. You could have a hypothesis that the lakes were gouged by glaciers and you could find plenty of evidence that supports your hypothesis. But you would still be (partially) incorrect. A better thing to do is to list many potential explanations of your phenomena and then test them all. What you may find is that there is a different "right answer" (or that there are multiple causes). The Great Lakes were occupied by glaciers, true, but they were river valleys before the glaciers, and some of them were river valleys because they were low areas as a result continental rifting that occurred more than a billion years ago. Only by proposing and testing multiple hypotheses could you find the best possible explanation.

So how does this apply to the common cold? I came down with a severe sore throat suddenly on Wednesday afternoon. I formed several working hypotheses as to the cause and the progression of the sore throat:
  1. strep throat
  2. a cold
  3. the intestinal flu that was rampant in husband's hometown
  4. tonsillitis
  5. just a plain jane vanilla sore throat
I devised experiments to test each hypothesis (i.e. watch the progression of symptoms)
  1. If strep then I would develop a high fever. If I develop a fever, I would get a strep culture.
  2. If a cold, my sore throat would dissipate when the post-nasal drip ceased and the nose blowing took over.
  3. If the flu, well, that one would be pretty obvious, don't you think? Intestinal symptoms should start within 24 hours of the beginning of the sore throat.
  4. If tonsillitis, I'm not sure. I've never had it.
  5. Plain-jane: sore throat would disappear without development of other symptoms.
So, many cups of Throat Coat tea and quiet hours on the couch later, I am happy to report that the method of multiple working hypotheses suggests that what I've got is merely a cold. And there's today's history of science lesson and personal anecdote all rolled into one. Here's hoping you all stay healthy.

5 comments:

Astroprof said...

Colds are annoying. Being exposed so much to colds from so many students, I guess that I shake them off rather quickly. Still, I get pretty grumpy when sick. The last one, though, worked itself into a sinus infection.

Get to feeling better.

Writer Chica said...

Hope you are feeling better. Glad to hear that it was just a cold. Thanks for the history lesson. Again, you ARE my main link to the scientific world.

ScienceWoman said...

To writerchica: that's quite a compliment!

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