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by Chris_Newton 2174 days ago
As someone who very much relates to the GP’s anecdote, I might suggest determinants as a good example.

As an undergraduate studying maths, I encountered a standard theorem in one of my first courses, which says that about 947 different conditions are equivalent to a matrix having a determinant of zero. I dutifully memorised these. I also dutifully memorised the algorithm for how to calculate a determinant. I might even have remembered some verbatim proofs of some of the equivalences.

However, I developed absolutely no intuition about what a determinant is. I had book knowledge, but no insight. It was a long time ago now, but I’m fairly sure that when I graduated I still did not truly understand even this very basic (by undergraduate standards) subject. I think it was probably a few years later, when I came across some of the same theory but in a much more practical context at work, that most of the connections in that equivalence theorem first “clicked”.

Meanwhile, here is what a gifted presenter with the right illustrations can do in about ten minutes:

https://www.youtube.com/watch?v=Ip3X9LOh2dk

The 2,000 or so substantially identical comments below that video are very telling.

Given the understanding you’d get with that quality of presentation, the equivalences I mentioned above would have been obvious and constructing the proofs from first principles would have been straightforward.

3 comments

In the process of learning about a family of algorithms in machine learning I also gained some physical intuition of determinants (same diagram as 3Blue1Brown, but applied in a different context of "squashing and stretching" probability mass): https://blog.evjang.com/2018/01/nf1.html
Awesome example, thank you!
This is awesome, determinants were one of the things that I never really understood during my degree