Believing in the existence of a soul is pretty much pointless. We don't know everything about the brain yet, but we know more than enough about it to know that it makes a soul, if it were to exist, obsolete. I was actually writing something about the soul not too long ago, so I'll just slightly alter it to make it fit the format of a discussion. Most of this was actually written to show that hoping for an afterlife is silly. I'll try to leave some of this out ("We don't want a debate about religion, do we?"), but since the soul is inheretly part of religion, and a religious concept, I hope you won't mind it much
BTW, this talks about the religious soul, not soul = life or whatever. Why would you call life "soul" when you can just call it "life"?
Have fun.
Okay, Let us start with a split brain. A split brain is when the corpus callosum (Simply put, the thing connecting the 2 halves of our brain) is damaged or cut. What this does is split the brain into 2 different parts, each with its own consciousness and memory.
In the following video you'll see someone who had his corpus callosum cut for medical reasons. You will notice how the left and right part function individually, unaffected by one-another. Note that this person's corpus callosum used to be intact.
http://www.youtube.com/watch?v=ZMLzP1VCANo
This is quite interesting, because this means that one brain can create 2 different memories, unaffected by one-another. So either this means that cutting the corpus callosum splits the soul into 2 halves, or recognising things (and therefore drawing logical conclusions based on these things) and memory isn't part of the soul.
Of course, amnesia, which isn't too rare, and which can be permanent, can also show you that getting brain damage either damages the soul, or that memory isn't part of the soul. Damaging a spiritual something through non-spiritual means seems rather weird, doesn't it?
Now, there might be people who claim that the brain connects the soul to the body, and that damage in the brain therefore damages communication. To counter this, I will now be showing you how changes in the brain can change the personality. I said change, not reduce. Just, a completely different personality.
1st, let us consider growing up. If you're young, you have a different personality than when you grow up. You all know puberty. Your personality during puberty also changes because of hormones (taking hormones can change your personality, I hope you're all aware of that). So, are hormones suddenly also a link between the soul and the body? Do hormones change your soul?
Now, you might think that hormones just irritate you, causing you to act differently or something, so on to the brain.
Traumatic brain injury, which basically is just damage to the brain, can have some nasty effects. One of them is a change in emotions and personality. Now, it's hard to find a specific video of this. Probably because I doubt anyone would want to record the personality of someone when you don't know he'll be suffering from brain injury. But nevertheless there are quite a lot of witness testimonies and informational videos dealing with this sort of problem. Do you really think that people (who do not have anything to do with religion whatsoever) would make videos like this if this were a lie? I'll show one, but just searching for "traumatic brain injury" and "personality" on you-tube gives you quite a lot of other videos.
http://www.youtube.com/watch?v=20JbO_ABo1s
So this basically demonstrates that changes in the brain can change, not reduce, the personality. So, either less communication with the soul (or mistranslated information due to damage of the brain) causes a change in personality, or the brain is the personality. Applying Occam's razor would show us that 2 is most likely the true one, because there are less hypotheticals, or even none at all.
Now this also undermines the concept of wanting to go to heaven, if damage to the brain causes mistranslation (which just sounds silly), then that would mean that not the person who's walking here on Earth, but something with a different personality, would go to heaven if the person would follow the guidelines of the religion. Note, I use Heaven here as whatever place you wish your soul would go to.
On to feelings or emotions. Hormones can obviously change these (mood swings during pregnancy, for example), and so can drugs, But I'll be focussing on the brain once more.
We are actually able to change how a person is feeling by implanting electrodes into the brain. Changing the settings can completely change the way this person is feeling. ( http://www.youtube.com/watch?v=JOl83Wku_rg ). Not that this is surprising at all, but this just means that how you feel is again not part of the soul.
And this is not all. Just consider dementia. As for example Alzheimer's progresses, the person affected by it is less able to recognise people, usually to the point where they are only barely able to recognise the people who are very close to them, or even no-one at all. This is very significant, as this means that the soul is not able to recognise even your relatives. If you were to meet them in an afterlife, you wouldn't even recognise them.
For even more examples, just check out the effects of lobotomy, drugs, traumatic experiences, strokes, insomnia, brain cancer, migraine, and so on.
(anti-heaven rant, if you just want to discuss the soul, ignore this.)
So, to summarise, we have concluded that the soul does not include:
Your memory. So, who you were is not included in your soul. If your soul goes to heaven, it will have no memory of what you did and who you were
Your personality and emotions. So if your brain goes to heaven, it won't act like you did, it won't be you.
Your conclusions based on observations. This includes your believes (for example, you would not believe if no-one told you about it, and you read nothing about it, would you?). So whilst belief might be a defining characteristic which will decide whether or not you get to go to heaven, it will all be gone when you go there.
What the soul could still be is stuff like imagination and free will. These have all been found to be the effect of the brain, but there's no point in discussing these, as there's no point in trying to make sure for example, your imagination goes to heaven, when all you imagined doesn't. (And yes, it doesn't, remember the amnesia argument).
And now you might be claiming that what's on your brain gets transferred to your soul and goes to heaven once you die, or something similarly. But that would mean that if you lose your memory somewhere along the way, or your personality changes along the way, or Alzheimer's gets to you, who you previously were never gets to go to heaven or hell, It was all in vain. This is especially frustrating in the case of dementia, as growing old meant you ruined your chances of having a soul which was more like who you were. Wouldn't this mean that committing suicide when you're at the prime of your life would be the best option, as your personality, memory and everything would still be optimal?
And what about little kids then? If their soul was what was on their brains, they won't be able to contribute much to heaven, would they? How about the soul of a foetus? That sounds like a rather pathetic thing to send to heaven in this case. And yet those who are pro-life seem to want to defend this soul at all costs...
But most importantly, this still doesn't solve the split brain problem. Do You suddenly get 2 souls along the way? Do both brainhalves form 2 different souls?
And what about people who are braindead? What would happen there? How about half braindead? Lobotomy?
So honestly, this funny little hypothesis creates more questions than answers, and would just be a way of trying to validate the irrational.
And then there's always the argument which claims that when you die, you die, but at a given point in time, you will be resurrected. But this just doesn't make much sense. When you die, your brain decomposes, it exists no longer. The same goes for the rest of your body.
But say that your deity somehow does magically reassemble everyone. I assume you expect eternal life after resurrection, but then wouldn't suicide at a young age once again be the best thing to do?
To recap, if a heaven exists, you're trying to send something which obviously isn't you, something which you could care less about, to some happy place. Why bother? Why not just forget about the after-life and make sure you enjoy your life here on Earth?
This is also one of the problems I have with reincarnation. If what you reincarnate to doesn't remember who you used to be, what's the point in trying to make sure that whatever you reincarnate to isn't, say, a rainworm?
(end of anti-heaven rant)
Also, to Ben, I believe we're nothing but chemicals and electronics. Many dumb things cooperating can form an intelligent entity, just think of flocks of birds or groups of sardines. Of course, with the brain, this happens at a more massive scale (way more neurons) and there's more communication. So no, thoughts and feelings have no actual substance beyond the chemical and electrical functions that cause them. They ARE the chemical and electrical functions which cause them.
Wallman out.