[quote="grannymh, post:6, topic:305711"]
In addition, CCC 355- 357 explains God's basic design of human nature
Where do the fixed electrochemical signals come from? What do these signals actually do?
The HowStuffWorks.com page on nerves discusses it pretty well. The Wikipedia entry on action potential discusses how this works in more technical detail.
Neural networks, real and artificial, are capable of amazingly complex behavior.
This is interesting. What is our consciousness, wherever it is, conscious of?
Let me think about that one... ;)
Who has seen a disembodied soul in order to know what it has or has not?
Actually, Aquinas delved into this, as other posters have replied. He discussed the different functions of soul in a way that prefigures modern neuroscience. The "sensitive soul" perceives the world through the sense organs (so souls without sense organs don't sense; the CCC entry on heaven says that in heaven, souls use "intuitive vision," not sight as we understand it). Aquinas said the "vegetative soul" moved through the body (so a soul doesn't move independently of the body). Lastly, he said that the "rational soul" contained our mental function.
In the 800 years since he wrote, cognitive neuroscience has shown us that mental function is dependent on the physical state of the brain, as stated above. Suffice it to say that following Aquinas, if a soul uses the physical nervous system to think and feel, a soul without a nervous system doesn't think and feel.
I do not mean to be silly....but it is hard for me to go from picturing a free floating disembodied soul to the end of the Creed in Sunday's Holy Sacrifice of the Mass.
The reason I bring it up is that frequently in popular culture, such as children's cartoons, when someone is shown as dying, a translucent figure that looks just like the person who just died rises up. Sometimes, they have wings like an angel. Other times they're shown rising (if they're going to heaven) or sinking (if they're headed to hell). But this pop culture image, which I think is similar to many people's conception of what happens when we die, is simply not what the Church teaches.
We die because we are mortal. Because our spiritual soul is immortal, we say at the end of the Creed:"I look forward to the resurrection of the dead and the life of the world to come. Amen"