How exactly does one phenomena completely preclude the other, though? There's phenomena that support a wide variety of theories on the subject. Just like we can say there's no fundamental support for personality apart from the brain's physical and chemical structure, because there are personality changes when said structure is altered, others say that the brain transmits stimuli in two ways, both from the soul and from the outside, and when its structure is altered, it may then become unable to interpret certain stimuli from either side, while not affecting the soul, kinda like Frumple said. None of the current methods and technology available can fully prove either hypothesis, so believing things are one way or another until then, is essentialy a matter of belief :v
Except a lot of people seem willing to take belief as fact, not unlike certain religious fundamentalists. Two sides of the same coin, one intentionaly interpreting available incomplete evidence as absolute, other disregarding available evidence altogheder, but not fully proven wrong either, and in the end we have Stephen Fry trying to fistfight the ghost of Martin Luther, while I'm throwing popcorn at them.
What I'm saying is, we need to keep trying to learn more things while keeping our minds open to all possibilities, so we don't end up throwing away certain hypothesis away simply because it doesnt fit exactly into what little we know.
And, as we've seen time and time again, Occam's Razor is about as infallible as plastic surgery on Michael Jackson.
FAKEEDIT: ninjas