Casual Physics Enjoyer

Obvious is a word for fools.

Last week, I had been trying to solve the first exercise problem in a mathematical physics book.

Problems early on in books are the easiest. And yet, I had spent four days days on it. I got nowhere. I have two degrees in mathematics, some research experience, and I still couldn’t get it.

I tried googling the answer, but nothing was really clear. All the explanations hinged on one supposedly obvious assumption (isometries in Euclidean space were affine maps), that everyone seemed to sweep under the rug. No one could explain why. Thinking it was my fault, I fell into a crisis of self confidence. Everywhere I looked, I couldn’t find why this assumption was true.

I got desperate.

Without any other options, I emailed a professor who used to teach me as an undergrad ten years ago. He is master of his craft, and one of the most brilliant people I’ve had the pleasure of learning from. I remembered ten years ago that he said something that was connected to the problem that I was trying to solve. You probably know his name, but for privacy reasons I will not say it here.

‘Hey Prof, I’m really struggling with this one question here, and if it’s obvious, then I must really be missing something’.

He explained why this one assumption was true. It involved multiple long lines of crystal clear, insightful reasoning. It turns out, there was a deep meaning to where this assumption held and why. And it took a whole page to explain the nuance.

As for my question on whether this was meant to be obvious, his reply:

‘It isn’t’.

This happens a lot. Don’t let people convince you that things are obvious.