That does not mean I think the scientific method is not a valuable tool. I just think it has limits. Of course arguments based on reason and objectivity are more likely to be correct than arguments based on superstition such as wearing lucky socks. That does not mean I think the scientific method is not a valuable tool. I just think it has limits.
Psychology can assume the first, though in practice assumes the second most of the time.
It should be noted that functionalistic positions would not change if it was somehow proven that no spiritual states existed or that mind was definitally not material. Well I'm an undergrad of religious studies and my main professor is a psychologist of religion if there ever was one. Philosophers, on the other hand, are a VERY hard sell. I changed my career plans after sitting on the advisment panel for a temporary spot at a dinky teaching college in Kansas. Philosophy is NOT a friendly field and don't fool yourself into thinking otherwise.