First off, let me just say this... Masamune Shirow is a genius, and Mamoru Oshii is amazing for putting Shirow's idea into an incredible anime film. Good stuff.
Ghost in the Shell brought up a number of interesting questions commonly associated with a number of our in-class discussions, although they're not always brought up. Some of those underlying themes are the questions that've been asked since the great age of technology began, as follows:
Can a "machine" be considered "alive?"
Can a "machine" have a "soul?"
I used quotations on purpose. Why? Most of the terms in quotations will have multiple definitions depending on who you talk to. What does one consider to be alive? What is a soul? These are questions that have been discussed far before the technology age began. Some of it has been argued with science, others with the traditions backing various religions. Personally, I don't think I could give you a definate answer to support what I think, but niether can you give me a definate answer to prove me wrong (and you can't say faith proves it; I'm not buying that excuse)!
Ghost in the Shell portrays technology in which they have been able to identify the existence of a person's soul. In most cases of definition, part of being "alive" means you must have a soul. Therefore, there can be a defined difference between a living organism and a machine. Machines can be created such that they have a soul within them as well, as if the soul was simply another manufactured product from a production line in a dark factory on a no-name street. This brings up a disturbing image of a future in which the soul is no longer considered a sacred or spiritual object, but rather a psuedo-physical one that can be crafted or destroyed. The thought of creating a machine and giving it a soul sounds promising to the lonely, but in order to gain something another thing must be lost. If a machine can gain a soul, what does it lose? What does humanity lose if machines gain a soul?
In addition, it's apparent that one's memories can be implanted, removed, or modified with the use of technology. It also seems possible that one's memories can be transferred to another location. As far as I understand it, it seems that the Major's brain is essentially organic, but that some of her psychological processes are mechanated. Does this mean some of her memories and brain functions have been cut-and-pasted into the mechanical subroutines of her mind? Such technology would be mindblowing (pun intended) and create a number of controversies almost instantaneously. If you could transfer your entire mind from an aged, dying body into a young, pseudo-human cybernetic body, you could continue living far beyond the normal lifespan of a human being. In addition, if your new mechanical body took some sort of damage that would normally kill a human being, you could just get some replacement parts (although in the movie it seems that the parts are not necessarily easy to get, as Batou had to get a replacement body for the Major/Puppet Master over the black market). Essentially, it could turn into an attempt to grasp at immortality.
Now let's couple this idea with genetics. What if we could manufacture a human body, organic in all senses of the word, and then transfer one's mind into it? You could continue your life this way, or perhaps live another life entirely. That sort of says something about reincarnation, now doesn't it?
Overall, Ghost in the Shell gave me a lot to think about. I saw it years ago, but I never watched it with this sort of mindframe before. I have to say I enjoyed the deep themes it displayed, and it'll keep me thinking for a while.
Now, a couple of other random thoughts that are essentially off-topic...
That tank was awesome. It gives a new meaning to the phrase "all-terrain vehicle." Those of you who have not had the chance to see the series, Ghost in the Shell - Stand Alone Complex should check out the mini tanks they use there if you liked the huge one in the movie. The little ones are called Tachikomas. They may appear in Ghost in the Shell 2 but I havn't seen that one... yet.
I... would like Batou's ridiculously huge cannon/gun. Sweet.