Reading the Comics, October 14, 2014: Not Talking About Fourier Transforms Edition
I know that it’s disappointing to everyone, given that one of the comic strips in today’s roundup of mathematically-themed such gives me such a good excuse to explain what Fourier Transforms are and why they’re interesting and well worth the time learning. But I’m not going to do that today. There’s enough other things to think about and besides you probably aren’t going to need Fourier Transforms in class for a couple more weeks yet. For today, though, no, I’ll go on to other things instead. Sorry to disappoint.
Glen McCoy and Gary McCoy’s The Flying McCoys (October 9) jokes about how one can go through life without ever using algebra. I imagine other departments get this, too, like, “I made it through my whole life without knowing anything about US History!” or “And did any of that time I spent learning Art do anything for me?” I admit a bias here: I like learning stuff even if it isn’t useful because I find it fun to learn stuff. I don’t insist that you share in finding that fun, but I am going to look at you weird if you feel some sense of triumph about not learning stuff.
Tom Thaves’s Frank and Ernest (October 10) does a gag about theoretical physics, and string theory, which is that field where physics merges almost imperceptibly into mathematics and philosophy. The rough idea of string theory is that it’d be nice to understand why the particles we actually observe exist, as opposed to things that we could imagine existing that that don’t seem to — like, why couldn’t there be something that’s just like an electron, but two times as heavy? Why couldn’t there be something with the mass of a proton but three-quarters the electric charge? — by supposing that what we see are the different natural modes of behavior of some more basic construct, these strings. A natural mode is, well, what something will do if it’s got a bunch of energy and is left to do what it will with it.
Probably the most familiar kind of natural mode is how if you strike a glass or a fork or such it’ll vibrate, if we’re lucky at a tone we can hear, and if we’re really lucky, at one that sounds good. Things can have more than one natural mode. String theory hopes to explain all the different kinds of particles, and the different ways in which they interact, as being different modes of a hopefully small and reasonable variety of “strings”. It’s a controversial theory because it’s been very hard to find experiments that proves, or soundly rules out, a particular model of it as representation of reality, and the models require invoking exotic things like more dimensions of space than we notice. This could reflect string theory being an intriguing but ultimately non-physical model of the world; it could reflect that we just haven’t found the right way to go about proving it yet.
Charles Schulz’s Peanuts (October 10, originally run October 13, 1967) has Sally press Charlie Brown into helping her with her times tables. She does a fair bit if guessing, which isn’t by itself a bad approach. For one, if you don’t know the exact answer, but you can pin down a lower and and upper bound, you’re doing work that might be all you really need and you’re doing work that may give you a hint how to get what you really want. And for that matter, guessing at a solution can be the first step to finding one. One of my favorite areas of mathematics, Monte Carlo methods, finds solutions to complicated problems by starting with a wild guess and making incremental refinements. It’s not guaranteed to work, but when it does, it gets extremely good solutions and with a remarkable ease. Granted this, doesn’t really help the times tables much.
On the 11th (originally run October 14, 1967), Sally incidentally shows the hard part of refining guesses about a solution; there has to be some way of telling whether you’re getting warmer. In your typical problem for a Monte Carlo approach, for example, you have some objective function — say, the distance travelled by something going along a path, or the total energy of a system — and can measure whether an attempted change is improving your solution — say, minimizing your distance or reducing the potential energy — or is making it worse. Typically, you take any refinement that makes the provisional answer better, and reject most, but not all, refinements that make the provisional answer worse.
That said, “Overly-Eight” is one of my favorite made-up numbers. A “Quillion” is also a pretty good one.
Jeff Mallet’s Frazz (October 12) isn’t explicitly about mathematics, but it’s about mathematics. “Why do I have to show my work? I got the right answer?” There are good responses on two levels, the first of which is practical, and which blends into the second: if you give me-the-instructor the wrong answer then I can hopefully work out why you got it wrong. Did you get it wrong because you made a minor but ultimately meaningless slip in your calculations, or did you get it wrong because you misunderstood the problem and did not know what kind of calculation to do? Error comes in many forms; some are boring — wrote the wrong number down at the start and never noticed, missed a carry — some are revealing — doesn’t know the order of operations, doesn’t know how the chain rule applies in differentiation — and some are majestic.
These last are the great ones, the errors that I love seeing, even though they’re the hardest to give a fair grade to. Sometimes a student will go off on a tack that doesn’t look anything like what we did in class, or could have reasonably seen in the textbook, but that shows some strange and possibly mad burst of creative energy. Usually this is rubbish and reflects the student flailing around, but, sometimes the student is on to something, might be trying an approach that, all right, doesn’t work here, but which if it were cleaned of its logical flaws might be a new and different way to work out the problem.
And that blends to the second reason: finding answers is nice enough and if you’re good at that, I’m glad, but is it all that important? We have calculators, after all. What’s interesting, and what is really worth learning in mathematics, is how to find answers: what approaches can efficiently be used on this problem, and how do you select one, and how do you do it to get a correct answer? That’s what’s really worth learning, and what is being looked for when the instruction is to show your work. Caulfield had the right answer, great, but is it because he knew a good way to work out the problem, or is it because he noticed the answer was left on the blackboard from the earlier class when this one started, or is it because he guessed and got lucky, or is it because he thought of a clever new way to solve the problem? If he did have a clever new way to do the problem, shouldn’t other people get to see it? Coming up with clever new ways to find answers is the sort of thing that gets you mathematical immortality as a pioneer of some approach that gets mysteriously named for somebody else.
Zach Weinersmith’s Saturday Morning Breakfast Cereal (October 14) makes fun of tenure, the process by which people with a long track record of skill, talent, and drive are rewarded with no longer having to fear being laid off or fired except for cause. (Though I should sometime write about Fourier Transforms, as they’re rather neat.)
Margaret Shulock’s turn at Six Chix (October 14) (the comic strip is shared among six women because … we couldn’t have six different comic strips written and drawn by women all at the same time, I guess?) evokes the classic image of Albert Einstein, the genius, and drawing his famous equation out of the ordinary stuff of daily life. (I snark a little; Shulock is also the writer for Apartment 3-G, to the extent that things can be said to be written in Apartment 3-G.)