If he changes his opinion, which I understand to be models of the brain in this case, and each iteration improves the model, then that is perfectly fine. It would be bad if someone did not change their view in case of inconsistent evidence.
For political opinions sure, but if he's changing his opinions so often ...
When you're a big scientific figure, I think that you have some extra responsibility to the public to only say things you're very confident about. Or otherwise very clearly communicate your uncertainty!!
