Thank you for the link! Very interesting read. I kinda knew about this stuff but reading about it in sources like the nlab would always confuse me. This, on the

Thank you for the link! Very interesting read. I kinda knew about this stuff but reading about it in sources like the nlab would always confuse me. This, on the other hand, feels very accessible. Incidentally, I studied algebraic geometry with a functorially oriented professor; one day, in passing, he said something along the lines of not wanting to use the axiom of choice in the proof of some result. At the time I didn't understand and I didn't ask for clarification, but the puzzlement stayed with me for a while. Having read this, it looks like his remark might have been related to this kind of stuff (e.g. chapter 12).