Math PhD student here. It seems to me that mathematical ability is a nebulous concept. I’ve noticed in courses I taught that grades tend to reward conscientious students who can “play the game” and do formal manipulations even if they don’t really understand what’s going on. Courses tend to move fast enough that very few students can keep up with all the concepts, so the ones who have trouble playing the game and don’t keep up with all the concepts have trouble.
Personally, I had little patience for that. I seldom memorized formulas. Either I knew them from repeated use or I just derived them on an exam. I always felt odd when I had to apply a technique or formula I didn’t understand. I would say that love of learning seems to have played a significant role. When I truly want to learn something and take pleasure in doing so, I’ll devour the subject. I have trouble making progress in topics I feel forced to learn.
I’ve noticed in courses I taught that grades tend to reward conscientious students who can “play the game” and do formal manipulations even if they don’t really understand what’s going on.
Calculus 2 is where I hit the limits of my conceptual abilities. I am very bad at “playing the game” in this way, so I haven’t moved beyond that yet.
I think it’s wrong to put too much emphasis on a contrast between “playing the game” and “understanding the material”, though. My feeling is that if I became better at playing games, paying attention to detail, being more conscientious about my work, then I would also improve my conceptual understanding after a while.
My feeling is that if I became better at playing games, paying attention to detail, being more conscientious about my work, then I would also improve my conceptual understanding after a while.
Indeed, the mathematical profession itself relies on this for the training of its members, because it doesn’t know how to train conceptual understanding directly—as described candidly by Ravi Vakil:
[Y]ou’ll go to talks, and hear various words, whose definitions you’re not so sure about. At some point you’ll be able to make a sentence using those words; you won’t know what the words mean, but you’ll know the sentence is correct. You’ll also be able to ask a question using those words. You still won’t know what the words mean, but you’ll know the question is interesting, and you’ll want to know the answer. Then later on, you’ll learn what the words mean more precisely, and your sense of how they fit together will make that learning much easier. The reason for this phenomenon is that mathematics is so rich and infinite that it is impossible to learn it systematically, and if you wait to master one topic before moving on to the next, you’ll never get anywhere. Instead, you’ll have tendrils of knowledge extending far from your comfort zone. Then you can later backfill from these tendrils, and extend your comfort zone; this is much easier to do than learning “forwards”. (Caution: this backfilling is necessary. There can be a temptation to learn lots of fancy words and to use them in fancy sentences without being able to say precisely what you mean. You should feel free to do that, but you should always feel a pang of guilt when you do.)
I seem to be unusual (among people attracted to advanced mathematics, but perhaps not so much in the LW cluster) in being mostly unable to tolerate such an approach.
My inability to deal with this approach is a good part of why I switched away from number theory after about three semesters of graduate school (I got my PhD in another area of math). The expectation that students would learn the advanced material via “fake it till you make it” was endlessly frustrating to me and actively bad for my learning and mental health.
To be sure, there’s some of this in most areas of math, but my admittedly limited impression is that the situation is worse in number theory and algebraic geometry than in some other fields.
In synthetic approaches to mathematical subjects, it’s not necessarily meaningful to ask what a mathematical object “is”, or “what’s going on”. It’s not about things being less than rigorous—rather, all that matters is the axioms and rules of inference you get to use in that particular area. ISTM that extending “tendrils of knowledge” can be modeled as making such ‘synthetic’ inferences, whereas backfilling involves finding different models of the same theories, to make conceptual understanding more feasible.
I’ll let you in on a secret: almost everyone hits the limit in Calculus 2. For that matter, most people hit the limit in Calculus 1 so you were ahead of the curve. That doesn’t mean no one understands calculus, or that you can’t learn it. It just means most students need more than one pass through the material. For instance, I don’t think I really understood integration until I learned numerical analysis and the trapezoidal rule in grad school.
There’s a common saying among mathematicians: “No understands Calculus until they teach it.”
Math PhD student here. It seems to me that mathematical ability is a nebulous concept. I’ve noticed in courses I taught that grades tend to reward conscientious students who can “play the game” and do formal manipulations even if they don’t really understand what’s going on. Courses tend to move fast enough that very few students can keep up with all the concepts, so the ones who have trouble playing the game and don’t keep up with all the concepts have trouble.
Personally, I had little patience for that. I seldom memorized formulas. Either I knew them from repeated use or I just derived them on an exam. I always felt odd when I had to apply a technique or formula I didn’t understand. I would say that love of learning seems to have played a significant role. When I truly want to learn something and take pleasure in doing so, I’ll devour the subject. I have trouble making progress in topics I feel forced to learn.
Yes, I’ll be discussing the points that you raise (in the context of other things) in my subsequent posts. Thanks for your interest.
Calculus 2 is where I hit the limits of my conceptual abilities. I am very bad at “playing the game” in this way, so I haven’t moved beyond that yet.
I think it’s wrong to put too much emphasis on a contrast between “playing the game” and “understanding the material”, though. My feeling is that if I became better at playing games, paying attention to detail, being more conscientious about my work, then I would also improve my conceptual understanding after a while.
Indeed, the mathematical profession itself relies on this for the training of its members, because it doesn’t know how to train conceptual understanding directly—as described candidly by Ravi Vakil:
I seem to be unusual (among people attracted to advanced mathematics, but perhaps not so much in the LW cluster) in being mostly unable to tolerate such an approach.
My inability to deal with this approach is a good part of why I switched away from number theory after about three semesters of graduate school (I got my PhD in another area of math). The expectation that students would learn the advanced material via “fake it till you make it” was endlessly frustrating to me and actively bad for my learning and mental health.
To be sure, there’s some of this in most areas of math, but my admittedly limited impression is that the situation is worse in number theory and algebraic geometry than in some other fields.
This is a really good quote, thank you.
“Young man, in mathematics you don’t understand things, you just get used to them!”—John von Neumann
In synthetic approaches to mathematical subjects, it’s not necessarily meaningful to ask what a mathematical object “is”, or “what’s going on”. It’s not about things being less than rigorous—rather, all that matters is the axioms and rules of inference you get to use in that particular area. ISTM that extending “tendrils of knowledge” can be modeled as making such ‘synthetic’ inferences, whereas backfilling involves finding different models of the same theories, to make conceptual understanding more feasible.
I’ll let you in on a secret: almost everyone hits the limit in Calculus 2. For that matter, most people hit the limit in Calculus 1 so you were ahead of the curve. That doesn’t mean no one understands calculus, or that you can’t learn it. It just means most students need more than one pass through the material. For instance, I don’t think I really understood integration until I learned numerical analysis and the trapezoidal rule in grad school.
There’s a common saying among mathematicians: “No understands Calculus until they teach it.”
Well, yes.
I didn’t understand a lot of math I aced until much later.
This may just be that you don’t really understand any area of math well until you’ve taught it.
I’ve known professors who decided that the best way to learn a new topic was to teach a class in it.