[quote name='Drocket']Healing is a lot more complicated than that. Yes, the blood will clot, eventually (but not as fast as it would if you could feel: when you're injured, your body releases chemicals to make your blood clot easier, and sends white blood cells to the area to help cut off the bleeding), but its simply not going to heal correctly. The cells in the area will keep growing and will eventually wind up covering up the hole (in a mis-mash sort of way, almost certainly leaving a giant scar), but it won't be the directed healing that's induced by pain (which increases bloodflow near the region injured once the clot is formed and causes the cells to reproduce faster.)
Healing is not a simple process by any measure. Its one that involves a lot of different systems, all of which act in response to the pain stimulus. This is why leprosy is such a damaging disease. Ultimately, leprosy does little more than dim your perception of pain - and without a lot of medical care, its essentially a death sentence.[/quote]
I know absolutely nothing about leprosy. I know that in cartoons and comedies they have limbs falling off, which I would guess doesn't happen. That's the extent of my knowledge. I do know there are rare instances of children born without the ability to feel pain (these children often die due to not knowing what is harmful), and their wounds heal like everyone else. I know a little about that, and that's what I've essentially been thinking of when arguing this portion.
It has no brain, granted, but who says that a brain is necessary? As you said, jellyfish have no brain either, yet they react to a lot of different stimuses in an 'intelligent' fashion. As for emotions and consciousness - prove that they don't have them (and actually, a lot of scientists and philosophers would be interested if you could prove humans have them, beyond random chemical interactions in the brain.)
I think you miss the point. The chemical basis of emotions and feelings do not mean they don't exist, and I would be suprised if you could find scientists who argue feelings and emotions don't exists, regardless of their cause.
And the evidence to indicate plants think and have consciousness is essentially zero. They have reactions, repair damage etc., but there is nothing to support your argument that I'm aware off, one I doubt you yourself believe.
The point I'm making is what you've admitted: there ISN'T a line where you can easily say "this is an animal, and that's not." We have some stuff that we can classify as animals, some stuff we can classify as plants, and a whole big fuzzy area in between.
But, again, the whole fuzzy area is occupied by things that aren't in the vegetarian debate anyway. Salmon, pork, beef etc. are well beyond that. Jellyfish (which may enter into the debate in some cultures) may be completely lacking in emotion and consciousness, and in that sense be similar to a plant, but they are biologically a world apart.
The question revolves entirely around the existance of 'souls'. If you don't believe in the existance of souls, then human 'thought' is nothing more than a chemical process. A complex chemical process, but a chemical process never-the-less. Why should the chemical process involved in human thought be special, while the chemical processes in carrots isn't?
I don't see what this has to do with chemical processes or souls. You and I live life everyday, we feel and have emotions, whatever the basis to that (and I don't believe in souls), they exist in us and without question in many animals (I have pet rats who ignore food at the prospect of human attention, I know iguanas have occasionally refused to eat, to the point of starvation, when given up by a previous owner etc.). The very fact that we can sit here, with different opinions and reactions, shows that, and whatever basis it has does not change that.
At best the question of plant awareness and thought is relegated to the highly unlikely, like most other unproved things with practically zero evidence.