Robdemanc wrote:
We don't really know what consciousness is or whether it is a product of the brain. I often think that single celled organisims have a consciousness and they don't have a brain. If we say that consciousness is a product of the brain then we are saying that only animals can have consciousness. I don't think its as simple as that.
But we do know what happens to people if their brain is damaged or on drugs. Drugs that affect the brain can alter our entire personality. So can brain tumors, neurodegenerative diseases, or brain injuries.
An injury of the temporal lobe may increase aggressiveness, cause memory loss, and can render people unable to recognize faces and objects. If the right temporal lobe is damaged, they may also become uninhibited and engage in greatly inappropriate behavior such as public masturbation. Frontal lobe injury can completely change someone's social behavior. People may become less spontaneous, have trouble expressing language or completely lose their ability to speak, and may no longer be able to solve complex problems.
If the parietal lobe is damaged, people may lose their ability to read and write, can no longer tell left from right, can't draw anymore and become unable to focus on more than one item at a time. And so on. When we look at these injuries, we can tell exactly which part of the brain is responsible for which part of our thought, memory, personality and cognitive abilities. Now, what do you think happens if the entire brain shuts down?
If our ability to do simple math or recognize faces can't exist independently from our brain -- which is evident in the fact that we lose these abilities and parts of our personality when the corresponding brain area is destroyed -- we can conclude that our consciousness and personality in its entirety is a product of the brain and cannot exist without it either.