There’s more going on here

At a new faculty orientation, a professor encouraged us rookies to teach intro courses and to keep coming back to teach them periodically. I didn't fully appreciate what he said at the time, though I remembered it, even though I left academia a couple years later.

Now I think I have an idea what he was referring to. There's a LOT of stuff swept under the rug, out of necessity, when teaching intro courses. The students think they're starting at the beginning, and maybe junior faculty think the same thing, but they're really starting in medias res.

For example, Michael Spivak's Physics for Mathematicians makes explicit many of the implicit assumptions in a freshman mechanics class. Hardly anyone could learn physics if they had to start with Spivak. Instead, you do enough homework problems that you intuitively get a feel for things you can't articulate and don't fully understand. But it's satisfying to read Spivak later and feel justified in thinking that things didn't quite add up.

When you learn to read English, you're told a lot of half-truths or quarter-truths. You're told, for example, that English has 10 vowel sounds, when in reality it has more. Depending on how you count them, there are more than 20 vowel sounds in English. A child learning to read shouldn't be burdened with a college-level course in phonetics, so it's appropriate not to be too candid about the complexities of language at first.

It would have been easier for me to teach statistics when I was fresh out of college rather than teaching a few courses while I was working at MD Anderson. As a fresh graduate I could have taught out of a standard textbook in good conscience. By the time I did teach statistics classes, I was aware of how much material was not completely true or not practical.

I was thinking this morning about how there's much more going on in a simple change of coordinates than is apparent at first. Tensor calculus is essentially the science of changing coordinates. It points out hidden structure, and creates conventions for making calculations manageable and for reducing errors. That's not to say tensor calculus is easy but rather to say that changes of coordinates are hard.

Related post: Coming full circle

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