Monday, January 14, 2008

Using The Word "Believe" In The Science Classroom: AER January 2008

Comments and discussion in reference to Kristine Larson's January 2008 AER article entitled "This I Believe Understand: The Importance of Banning the B-Word from Science".

This month, AER published a paper by Kristine Larson on the use of the word “believe” (she refers to it as the “b-word”) in the science classroom. Larson’s article contains a discussion of the abundant misuses of “belief” in the lay presentation of science, including examples of “theological handwaving” by many of the successful popularizers of physics and astronomy.

Larson’s argument is that when scientists, science articles and science textbooks, use the words “believe” or “belief” (e.g. “Biologists believe that evolution is the best explanation for the development of life.”), it is confusing to the general public and to students. She says that the overuse of the word itself may contribute to a general sense of relativism among students: that science and religion are both “belief” systems, and you can’t know if either is right.

Larson demonstrates the entrenchment of the “b-word” in popular books, articles and textbooks. Her article’s main suggestion is that we should be removing the word from our explanations of science. I agree.

Science is in the business of developing models of the world. Accurate models are the ones that can survive repeated testing in experiments and against observations. For this reason, I think teachers should be constantly referring to the ideas of science (e.g. the Big Bang, General Relativity, Newtonian physics, etc) as models. Every time a model is discussed, we should refer to the observational/experimental evidence for it.

For several years now, I have consciously tried (as Larson suggests) to “ban the b-word” from my classroom speech. Rather than say: “Astronomers believe that…”, I find it better to say “Astronomy have confidence that…”. The distinction may seem small, but in the minds of students, semantics is important. In all of the science courses I teach (not just astronomy), I make it a point to go over several words that scientists use differently, such as “belief”, “theory”, “hypothesis”, “argument”, etc. I model my discussion after a chapter in a short book on science philosophy entitled "Just A Theory: Exploring the Nature of Science” by Moti Ben Ari. The chapter is called “Words Scientists Don’t Use: At Least Not the Way You Do” and is entertaining and accessible enough to assign as a reading for students.

When it comes to all the models that we sometimes hear referred to as “just a theory”, I have a favorite tactic: in addition to using the word “confidence”, I also point out the implications if these ideas were not accurate. Students (and people in general) often do not look for evidence that refutes their ideas or hypothesis, so I think it is important to constantly point out alternate outcomes and predictions.

For example, I like to point out that if general relativity were not an accurate model of nature, then global positioning systems would not work as well as they do. If special relativity were “just a theory”, then many of us could not flip the switch on the wall and expect the lights to turn on (since nuclear power accounts for a good portion of electricity generation in the US). If evolution through natural selection were not a good model of biology, then you might as well stop taking antibiotics.

When confronted with concrete applications of a model, I think that students will be more accepting later on when it comes to further implications of the same model. Accepting the expanding Universe model may be easier when students understand the observations that lead to it; even easier when they realize that redshift observations use essentially the same experimental (though not conceptual) physics that police radar guns use.

Larson’s article on the “b-word” ends with a bit of action research she did with a small class of non-major honors students. She gave her class the following open response question:

“You tell your roommate about this course, and they say "I don't believe in the Big Bang. It's just some stupid theory and there's no evidence for it. Besides, you can't believe in God and the Big Bang." How would you use what you have learned in this course to counter all parts of their argument?”

Larson’s description of the disappointing results is not surprising. Even though the question has explicit instructions to counter “all” parts of the argument, it seemed few of the tested students did so. Her sample comes from a non-major class on science and science-fiction, and she does not gives us many details about the class organization, goals, or pedagogical style, except that they discussed the concept of “non-overlapping magisterial” and the Big Bang model. Even so, I would not be surprised to see similar results in many intro astronomy courses. In the past, I have used questions not-unlike Larson’s on exams. Recently, however, I have used almost completely multiple-choice exams in astronomy. But, as Larson points out at the end of her paper, such assessments can easily fail to demonstrate whether or not a student can articulate the difference between a scientific theory and a belief.