What is the mind? Is it a product of the brain, or does it come from somewhere else? Is there a ghost in the machine? A number of things have brought this source of controversy to my mind recently. One is that I just finished the second season of Ghost in the Shell: Stand Alone Complex (not as good as the first season). The Ghost in the Shell franchise is largely an exploration of the implications of mind/brain duality and how it may actually become a reality as technology improves. Another is that I'm still reading Gödel, Escher, Bach: An Eternal Golden Braid by Douglas Hofstadter, a book that (among many other things) is largely about the origin of consciousness. Yet another is that there was a great party at the Mind/Brain Institute here at Hopkins last Friday. The final thing is that over the weekend I have gotten into some arguments with anti-choice people on YouTube (I know, bad move). First, a disclaimer -- here are the things that I believe, after a lot of reading and thinking:

• The mind exists as a result of things that happen in the brain.
• As it stands now, the mind cannot exist without the brain.
• It is conceptually possible that the mind could be 'liberated' from the physical hardware of the brain, but it would require some other equivalent physical hardware. The most computationally difficult and brute-force version of this would be to accurately simulate a physical brain on a computer.
• Humans are not the only conscious animals on this planet.
• Not all humans have the same level of consciousness. For instance, a baby in the womb or even a newborn is not likely conscious in the sense that adults or older children are. Probably many animals are more conscious than a one-year-old.

The alternative view, as far as I can discern it, is that the mind is something special that sort of "sits on" the brain, but can be liberated from it should the brain fail (read: die). This consciousness (or "ghost") can then go on to lead an afterlife. This is an extremely common perception, though it's highly unlikely, and it is the basis of some very common and heated controversies. It leads to statements of belief (contrasted with mine above) like this:

• As soon as a zygote is formed, it has a soul and is a person. It has feelings and cries out in pain if aborted, thinking "Why does my mommy not love me?"
• Humans have a soul and are special. Animals do not, and are not essentially 'special'.
• When the body dies, the soul lives on. Its future can contain things like heaven, hell, joining with the universal consciousness from whence it originally came, and so on.

This is why anti-choicers insist that abortion is murder. They will swear up and down to you that abortion is taking a "life", but try to pin them down on what "life" is and why it's more valuable than the life of the mildew in their shower or the pregnant woman, and they start to stutter and dive into circular logic. We can pose some difficult questions that will reveal this:

• What is an aborted foetus's soul like in Heaven? Does it remain always a baby? Does it grow into an adult?
• Do people with life-long brain dysfunction on earth (say, from Down's Syndrome) become different, more intelligent, and function better when relieved of their physical brain?
• Do people who have suffered head injuries on earth that allow them to survive but damage their ability to function, or people who have survived a stroke regain full function in the afterlife?

These questions are designed to bring attention to conflicting beliefs held within the same mind. That is, if one believes that a head injury causes its mental effects via damage to the brain, and not because it allows a demon into the soul, the rest of the ghost-in-the-machine belief system comes into question. The latter explanation is still accepted by some uneducated people (think rural west Africa) and crazy people in the developed world. The questions make it harder for people to rest assured that they hold reasonable beliefs on the nature of the brain and that these beliefs do not jeopardize their religious convictions. What are your views on the subject? Do you disagree with me? Can you think of similar and better questions to bring out this sort of thing?