Day of the Golem
Yesterday, we noted that Ramban takes the view that a human being has three separate souls (or "life-forces"): the growth-nature of a plant, the animate life of an animal, and a rational intellect superimposed on top of that. Ramban brings various proofs for his view, one of which is especially intriguing and relevant. He quotes the Gemara about Rava creating a man - a golem - which he sent to Rabbi Zeira. Upon discovering that this "man" could not communicate, Rabbi Zeira bid it to return to dust. Ramban does not elaborate upon exactly how this proves his point, but apparently it is because this golem must have possessed a nefesh habehemah, since it was animate, and yet we see that it did not possess a nefesh hamaskeles, since it could not communicate. Since it possessed one and not the other, this shows that they are distinct entities. (Note that it also shows that a man with an animal soul and no rational soul can exist after Creation.)
There is another important point to note with regard to this story of the golem. Rav Yaakov Emden, citing Chessed L'Avraham, deduces from Rabbi Zeira's destruction of the golem that it is permissible to kill it, and explains that this must be because it only has an animal soul, but not a human soul.
Note that this post still did not argue that according to Ramban, someone who is brain-dead has lost his rational soul. We will discuss that possibility in a forthcoming post. But it does seem clear that according to Ramban, it is theoretically possible to have a person who is just as alive as an animal, and yet is lacking a rational soul, and whom it is therefore halachically permissible to "kill," since he is not humanly alive.
In other news - for details of my forthcoming lectures at the Bridge Shul in Washington Heights on Feb. 13th, see this flyer.