This essay by the same person who answered the mathoverflow post greatly expands on the ideas in the post. https://arxiv.org/pdf/math/9404236.pdf https://arxiv.

This essay by the same person who answered the mathoverflow post greatly expands on the ideas in the post. https://arxiv.org/pdf/math/9404236.pdf https://arxiv.org/pdf/math/9404236.pdf It’s a great read for young people interested in mathematics and influenced me while in undergrad deciding to persue a PhD in math. Thurston, the author, was one of the best mathematicians of his time.