You seem to be claiming the 'mind' as some sort of intermediary between the physical and the immaterial spirit. I am intrigued by this idea and how you see it working.
Given the example in the OP what do you think happens to the spirit as a result of the physical tumour? Anything at all? Is this spirit self a version of 'you' that is free from all physical effects? Or just some? Is it a version of you that is free from behaviour affecting hormones (e.g. testosterone)? Free from disease (e.g. alzheimers)? Free from the effects of ageing? Free from the effects of all physical experience?
Is this spirit version of 'you' something that exists unchanged your entire life? If it does change then what things cause it to change and what things don't? How do you decide?
Well fuck, I don't know. I supose I could speculate for you, but I'm just making this shit up:
I'd see the mind as the gateway to the spirit. The mind is housed in the brain, lets say its a lense. If you mess with the brain, or mess with the glass in the lense, then what you see that has came through has changed. Not necessarily changed on the other side, but the result you see is different.
The physical affects the mind, so when the sprit is comming through that affected lense, it could be distorted. Here, comming through would be the outward expression of your behavior and/or the inward experssion of your thoughts, which too, can end up deciding your behvior. Its as if we're all a bunch of spiritual beings tapped into this physical world as a way to interact with each other and develop in preparation for the afterlife, which is entirely spiritual. I also see the spirit as emerging along with physical body, as if there isn't a place where the spirit sits around existing waiting for a body, but rather that the spirit emerges as the individual does.
So Fred (from the OP) seemed to not have a pedophilic spirit, but it came out as pedophilic after being distorted by his mind, because of the tumor in his brain. This assumes there's qualities to the spirit that affect our behaviors.
I do think the sprit could change too. As you get older and have interacted with so many people (other spirits) and learned so much, you grow spiritually too. You might even get more bitter. I see young children as less spiritually developed as adults. I think our spirits need this time here in the physical world, so they can interact with other spirits through the minds of the people as they physically interact. So yes, I'd see things like hormones and disease having an indirect effect on the spirit, as long as they affected your mind. So the stubbing of your toe, itself, would not affect your spirit, but how that impacted you mind, say through anger or something, could and/or would.
I suppose that underdeveloped spirits might have an afterlife similiar to underdeveloped people in the physical worlds do, a gradually limited view down to nothing at all. Too, maybe some of those monks have an overdevloped spirit that plays a more significant role in the afterlife.
I think that there are some genuinely bad people, as if they had an evil spirit or something, and visa versa. I don't know if they'd have started out predisposed that way, or if it would have been a result of how their spirit developed, or maybe a little of both.
What do you think constitutes a valid reason for the believing that a disembodied spirit is responsible?
I don't really take the stance that the spirit actually does exist. I honestly don't know. I approach it form the angle of, assuming it does exist, what would what we do know about our world mean for that. And I prefer to keep things consistant. So obviously the brain affects the mind... if the spirit exists, what would this mean for it... If the spirit doesn't exist, then this is just mental masturbation.
CS writes:
Yeah, but I don't have any reason to think the CIA's involved...
Well what
would constitute a valid reason for thinking that the CIA were using undetectable thought rays?
You changed it from invisible to undetectable.... how would the CIA even know if they were using undetectable rays?
"Have you fired the undetectable rays?" "I dunno, sir, but I'm not detecting them."
So I wrote out my reply, and then have been distracted awat from my desk a few times, and then have been going back and adding struff in here and there so hopefully its not too disjointed.