https://m.youtube.com/watch?v=bM9bYOBuKF4

The closest is at https://youtu.be/bM9bYOBuKF4?t=148 "That's the statement of the hypothesis, but it's a model, it's not completely true, no models are completely true. They're approximations to the world. The question is, for what purposes are they a good approximation. As far as I'm concerned, they're a good approximation for almost every purpose."

I think you've combined that with the aphorism commonly associated with George Box - https://en.wikipedia.org/wiki/All_models_are_wrong .

If the interview on YouTube contains your quote, then please link to or give the timestamp. I only skimmed the closed-captions.