Over at the Republic of Math, Gary Davis launched a preemptive strike on Thursday's upcoming #mathchat topic: "Does the nature of mathematics change as students get older or is it only the teaching methods that change?". His conclusion? Neither. I would tend to agree with this, but I'm going to play devil's advocate here and argue a different perspective.
Looking at this from the overall historical perspective, the "nature of math" has not changed very much over the years. The concepts at the core of mathematics, like quantities and patterns, are the same as they were thousands of years ago. The teaching methods for encouraging development also remain fundamentally the same as students age. Teachers seek to identify a student's present level of understanding and design learning activities that will bring that understanding to the "next level". From this perspective, neither the nature of math nor methods of teaching change over time.
However, there's something interesting in how this #mathchat topic is phrased. The question is not "does the nature of math change over time?" but rather "does the nature of math change as students get older?". If we concede the former point about the nature of math remaining the same over time from a historical perspective, the phrasing of the #mathchat topic hints at an alternative interpretation. Redirecting this question to the reader:
Did the "nature of math" change as you got older?
My answer to this is "Yes". The "nature of math" became more and more refined as I was exposed to new mathematical ideas. In particular, my preconceived notions about "the nature of math" were shattered into pieces when I learned about this guy:
Around the turn of the 20th century, Russell, Whitehead and Hilbert were attempting to build a solid foundation for mathematics using logic and set theory. This is more or less how I thought of the "nature of math" prior to college. I thought that if I only understood the basic rules of the "math game", I could figure out anything I needed to from applying those rules in a logical manner. It turns out I was wrong.
In 1931, Gödel published his famous Incompleteness Theorem. This result proved that the kind of system that Russell, Whitehead and Hilbert were attempting to create would either be incomplete or inconsistent. Likewise, this theorem single-handedly destroyed the concept of "the nature of math" that I had built up over the years. In its place I started to form a new concept about the "nature of math". Gödel had taught me to start looking at mathematics from outside the box.
Some other works that altered my notions about the nature of math were Turing's proof that the Halting Problem is undecidable and Cantor's Diagonal Argument. There are many parallels between all three of these results. What really resonated with me was the metacognitive component to these proofs. The nature of math had shifted from thinking about how I could play within the rules of the game, to thinking about how those rules could be bent or broken. Instead of "thinking about math", I started "thinking about how I thought about math".
This change in my perception of the nature of math not only influenced my future learning, but also changed how I thought about previous topics. The Republic of Math article mentions trigonometry, which is one of those areas that I was forced to revisit with this new perspective. As Gary notes in this and previous posts (here and here), there are lots of problems with trigonometry's reliance on triangles. Under my new "nature of math", the assumption that triangles needed to lie in a Euclidean space was no longer a safe assumption to make.
My background as computer programmer also altered my conception of trigonometry. Because trig functions and square roots can be computationally expensive, I developed a habit of avoiding them whenever possible. Most of the time I can get the data I need from a dot product instead of working with angles. Instead of using the distance between points, I'll often use the square of the distance as my metric. I'd learned to not just solve the problem, but to reflect on how I was solving the problem and try to optimize that process.
This brings me to the second part of the #mathchat prompt, which is "do teaching methods change as students get older?". Earlier I discussed the notion that the teacher should identify a students level of comprehension and guide them towards the "next level". With this trigonometry example, we can see that this model is overly simplistic. Math is not linear. Instead, the teacher must not only identify the student's current conception, but also which path that student is following so they can encourage them in that direction. If students are starting to think about trigonometry in terms of vector dot products, guide them towards linear algebra. If students are starting to think about triangles on spherical surfaces, guide them towards non-Euclidian geometry. Experienced educators like Gary are probably very adept at this. However, I think the reality of the situation is that most math teachers are not.
From the perspective of this student, the "teaching methods" did not change as I got older. With one exception, my math teachers adhered rigidly to the following procedure:
- lecture to blackboard for entire class period
- assign dozens of homework problems
- test on material
- rinse and repeat
How many math classes have you taken that followed this pattern? How many did not? There is an urgent need for the kind of teacher training Gary describes, where the focus is on personalized student development. Too many teachers are caught up in teaching the content, when they should be facilitating student learning instead.
Does the nature of mathematics change as students get older or is it only the teaching methods that change?
Yes, a student's model of the "nature of math" can change as that student grows older and discovers new results from the field of mathematics. I also think it's arguable that the "nature of math" is not necessarily static, as presumed above, but that Gödel's Incompleteness Theorem fundamentally changed the "nature of math" by using mathematics as a tool for analyzing itself -- giving birth to metamathematics.
No, teaching methods do not change as the student grows older, but they do vary from teacher to teacher. In general, I think the "typical math teachers" need to take a cue from Gödel and start thinking more outside the box. The mathematics classroom needs to shift from its lecture/homework/test/repeat cycle, where math is essentially taught using an "argument from authority", to an experimental environment where students are encouraged to question the information they receive.