Nobody understands quantum mechanics

Why it stays with me

Feynman said this in his lectures The Character of Physical Law, and he was one of the people who understood quantum mechanics best. His “sum over histories” approach is at the heart of how The Grand Design explains the universe.

He didn’t mean that the theory is vague. It makes some of the most precise predictions in all of science. He meant that it refuses to fit into everyday pictures of how things behave.

I find that reassuring. If quantum mechanics feels strange to me, I’m in good company. The lesson is to trust the mathematics and the experiments, and to accept that intuition built for everyday life won’t always work for the very small.