Yeah I didn’t get that one at all. He did mention that they excluded the possibility of normal background activity, and it did seem there was some aural response function at work. He seemed particularly impressed that the response was only to meaningful sentences and not individual words, but I have no idea how that is supposed to support his case and “refute materialism”.
Hypothetically, I’d like to see a patient ask him, “So Doctor, you can guarantee that my mind will be unaffected by this brain surgery? No? Well, are there some aspects of my mind that you can guarantee will be unaffected? No? Well…”