Here's my current (originally April 2020; updated March 2021) views on 3Blue1Brown's math videos:
- he puts in a lot of effort into the visualizations, so they look pretty. these visualizations are actually pretty good ones (i.e. not just pretty, but actually helpful).
- the videos contain real math, not the kinds of fake math that you see in a lot of math/physics popularizations. (so to give an example, i think numberphile is much worse in this regard.)
- i think he also stresses the intuition for some things (that many books don't). here are some examples of that in his neural networks videos: https://issarice.wordpress.com/2019/01/06/2019-01-06/
- he doesn't emphasize enough that actually learning math requires so much hard work and so much time. i think it creates this kind of illusion of understanding/competence in viewers that i think is harmful. it's not worse than in other popularizations of technical subjects, but it's still bad. sure, you could say that this is a problem with the audience rather than his videos -- for the motivated student who knows that actually understanding math requires lots of practice, his videos can be a great supplement to a textbook and tutor. but i have high standards for pedagogical material, and often complain about textbooks too for not containing enough intuition, so i feel i am being fair here.
- i think what i don't like is when people over-praise his videos, because they aren't really a substitute for actually getting down and going through the details (which his videos don't cover). i don't like the fact that when people bring up math pedagogy at all, they bring up 3blue1brown, rather than something else (say, Michael Nielsen or terence tao or tim gowers).
- in the long run, i think this kind of adhd "you don't need to do any work to learn math!!!" videos could attract attention away from the most important sorts of math pedagogy. for example, a particularly bright and smart person comes into the field, and thinks working on that kind of thing is the most important goal. you know, like plausibly that already happened because something convinced grant sanderson to start making these videos, and it could have been a slightly crappier math visualization product. and by now there are several copycat youtube channels and people using his manim animation engine.
- i'm skeptical of viewers' ability to use videos as a tool to really further and retain their understanding. my guess is that like 99.9% of people just watch the video, then forget about it. there's no force that pulls people back to review the material, to continue thinking about it, to try to reinvent it, etc.
"""There's a flipside to this emotional connection, however. We've often heard people describe Sanderson's videos as about “teaching mathematics”. But in conversation he's told us he doesn't think more than a small fraction of viewers are taking away much detailed understanding of mathematics. We suspect this is generally true, that high affect videos usually do little to change people's detailed intellectual understanding. Rather, the extraordinary value of the videos lies in the emotional connection they create.""" https://numinous.productions/ttft/ -- I can't disagree with this. But do the viewers know this, or are they fooling themselves into thinking they are actually learning math? It's good that Sanderson himself is not deluded here, but I'm worried he is still deluding his viewers.