Over the last few days, we have been exploring Ramban's view that a person's nefesh hamaskeles - rational soul - is distinct from his nefesh habehemah - animate soul. Ramban is of the view that a man who lacks a nefesh hamaskeles (such as Adam before he was given a rational soul, and a golem) is no different from an animal, and may be killed just like an animal.
Would Ramban consider a brain-dead person - someone who lacks even the brain activity necessary to regulate breathing, let alone any more complicated mental activity - to lack a nefesh hamaskeles? I think that he may well even consider such a person to lack a nefesh habehemah. But let's discuss the evidence that Ramban would consider this person to lack a nefesh hamaskeles:
- Nefesh hamaskeles means rational soul. Someone who is brain-dead has zero capacity for any form of rational mental activity. (I am well aware that later authorities ascribed all kinds of kabbalistic/mystical aspects to the soul. But Ramban only makes mention of it serving to distinguish man from animals in terms of the mental superiority that it grants.)
- Based on his argument from the golem, it seems that Ramban considers that one can assess whether someone has a nefesh hamaskeles via observing if they have the capacity for communication/ intelligence.
- All bodily functions - sufficient to produce a man who can function to the same degree as an animal - are controlled by the nefesh habehemah. There is no function in the body, in terms of breathing, eating, moving, etc., for which the nefesh hamaskeles is required. So the fact that a brain-dead person is breathing and has blood flowing through his veins is no indication whatsoever that a rational soul is present.
Some people are wondering why I am discussing the obsolete medieval views on various aspects of life/soul. First of all, this is for those who are not satisfied by standard rational arguments for brain-death, and want to see it rooted in traditional sources. Second of all, it is not so relevant that Plato and Aristotle are obsolete; the point is that Ramban accepted that a human body which is breathing, eating, etc., may not be rated as possessing the life of a human being. This is a value judgment, not a scientific judgment, and it is one which is very relevant to brain-death.
In summary, then, I think that it is clear that Ramban would maintain that a brain-dead person is considered to have already died as a human, and remains alive only as an animal (if even that), like a golem and like Adam before he received his rational soul. As such, according to Ramban, it would not only be permissible, but even mandatory, to take organs from such a man in order to save the lives of human beings.