I’ve been thinking about a pedagogical question lately. When teaching introductory classes, why do we spend so much time on history, especially the bits of history wherein the ancients (or not so ancients) end up being very, very wrong?
In physics and astrophysics alone, I can think of:
- The geocentric models of the universe
- Aristotle’s view of gravity (wherein heavier things fall faster)
- Lord Kelvin’s ideas about the sun is powered (via thermal collapse) — and the subsequent young age of the earth.
- The Luminiferous Aether.
- Einstein’s “greatest blunder,” the cosmological constant, and for that matter, the entire concept of a static universe (the “perfect cosmological principle,” as it was known).
- Van Maanen’s suspiciously large proper motion measurements.
- Kapteyn’s (and Herschel’s) sun-centered model of the Milky Way.
- Penzias and Wilson’s attempts to get rid of the signal that turned out to be the Cosmic Microwave Background (virtually everyone includes the detail about the bird poop).
and that’s just off the top of my head.
We (and by “we” I mean physics professors everywhere — apologies to those who break the mold) teach these things because we say that it’s only by learning about the mistakes of the past that we can avoid repeating them. Sure, I suppose that’s true. Mistakes are, after all, part of the scientific method.
Take the aether (please!). In almost every class I’ve ever taught (and certainly in every class I took), when we start talking about relativity, the aether appears out of nowhere, and disappears just as quickly. We never introduce aether until the instant before we talk about how the Michelson-Morely experiment demonstrated the constant speed of light. In other words, we introduce a new concept just to say that it’s wrong!
Or consider how long we spend on the geocentric model of the solar system, a philosophical point to which we return when we talk about Kapteyn. “Don’t assume that we’re special,” we intone sagely. “History has proven us wrong in the past!” And there’s a legitimate lesson there, to be sure.
However, I can’t help but feel like there’s also something a little smug about the whole practice. “See here, there was a great genius who discovered something important, but he or she was wrong about something. Weren’t people dumb? How grand it is to live in such an enlightened age!”
There are those who want to point to those stories from the past as object lessons about assuming that we’re right, but that just adds fuel to the worship of questioning conventioning wisdom. Further, the lessons of history (in principle, at least) give us powerful arguments against the pseudoscience of today. But do they really? I’d be interested in hearing from other educators — or students for that matter. What do you really take away from these discussions?