It's controversial because of how specific the hypothesis is, now novel the physical mechanism would be if it existed, and how little evidence there is that it exists. I don't think it's controversial because people that evolution couldn't possibly explore that possibility space. The fact that evolution explores a very large possibility space doesn't mean that anything you can conceive of must exist. I mean humans aren't even capable of biological flight, and we know that has evolved multiple times!
Penrose has 2 different theories really. 1 is that there are quantum effects involved in consciousness.
2 is that microtubles are directly involved. He feels fairly strongly about 1. He doesn’t feel strongly about 2. He is very open to it being incorrect and just thinks it’s an interesting theory to explore.
