In theoretical neuroscience, I've recently had to become more familiar with renormalization groups and coarse-graining methods when investigating potential power law and critical behavior in neural systems. The ideas started in quantum field theory because people invented quantum field theory. In the renormalizable theories, you only have to fix a finite number of parameters in order to do that. It got a bit of a bad reputation because it's kind of like making sense of infinity minus infinity, but really it was perfectly respectable all along.