IQ tests are pretty worthless, but leaving that aside, consciousness is an issue, and so is quality of life. Somebody without a higher brain does not have either. Terri has a brain stem and that’s it. In fact, maybe the example of IQ tests raise a good point: you need to be aware of the world around you to take one. Zero awareness is not a bad practical point to make that distinction.
There is no dispute to be had, in my mind, that Terri Schiavo is alive. Her body is plainly still functioning in an extremely limited way. Because her brain is gone, the individual who had Terri’s personality, or conciousness, or whatever term you like, however, has been dead for fifteen years. When people talk about life, generally speaking that is what they have in mind: thoughts. Not functions that continue automatically like breathing and a pulse. They want their conscious mind to continue to exist so they can be a part of, interact with, and appreciate the world around them. I don’t think it’s wrong to say it the way most people in the other threads have expressed it (their words vary of course): she is practically dead. If it’s better for me to split hairs, Terri Schiavo alive and everything that made Terri Schiavo “Terri Schiavo” is dead. The person is dead, the corpus happens to still be going by way of freak circumstances.
I disagree with your comment about Christopher Reeve’s speech. It’s not that hard to tell whether someone understands you or not even if they can’t speak to you. In fact, sometimes they speak to mask their understanding. 
No one is ‘demanding that she die,’ the issue is about allowing her to die. Even if you reject the evidence that’s what she would have wanted [the entire basis for the court rulings of the last five years], what remains for her, and objectively, who would want it if they were given the choice, ‘die or live like this?’ Same thing she’s endured for the last 15 years: some nagging health problems, no awareness of her surroundings, the feeding/hydration tube, the urine tube, digital stimulation to make her crap in her diapers, brain rotting in her head, no chance at recovering any level of consciousness. Quality of life is an important idea for people, and even unscientific TV polls show you’ll find few who would want to go on like this.
I do think consciousnes of the outside world is where most people draw the line, and while a number of people here seem to have issues with the idea of drawling lines, I think that’s reasonable. People in a lasting coma don’t have awareness of the world either.
Could you rephrase this? I don’t understand. Unless I’m very underinformed there is no legal point where the law says “they aren’t going to get better.” Nor is there a point where the law says “because they are not going to get better, you have to pull the plug.” Whoever is charged with making the decision gets advice from the doctors about whether the comatose person could get better or not and what is likely to happen. The law doesn’t enter into it except for the fact that everyone is entitled to refuse medical care, and if the person who is being treated is not able to make that decision, someone else does.
I don’t think anyone is making judgments about what kind of people should live or die; your OP implies someone is advocating euthanasia of the disabled and the question is “who is disabled enough?” That’s the same ‘rights of the disabled’ rhetoric some rightward elements have dishonestly tried shoehorn into this debate. It’s more about what kind of circumstances those people themselves would prefer to live or die in. I would rather be dead than live as Terri Shiavo is, and the next time I’m in New York in about a month, I’ll sign a document to that effect. So will my mother.
