I suppose the main issue is the brain is a huge consumer of oxygen and nutrients. (One stat I read said that it uses 30% of our energy, thus - the reason why high intelligence is a rare occurence in the animal kingdom, you’d better have a really good evolutionary advantage to put that sort of need onto the system). I suppose one could take advantage of the “drowning reflex” which allows chilled brains (cue zombie jokes) to survive 10 minutes to half an hour without oxygen.
The trope has been beaten to death in SF. IIRC, one of the Gil Hamilton ARM stories by Larry Niven uses it, wasn’t there some stupid movie (The Island?) where clones were raised as a future receptacle for rich people to transplant their brains; several other such stories over the years…
The law does not have a provision for this simply because it is currently impossible. When it is a real situation, there will be laws drawn up, or else the courts will decide in lieu of the legislators.
No doubt the obvious will prevail - the brain is the source of all personality, it seems to us. Therefore, just as brain death determines the termination of the person, even if their heart, liver, kidneys, etc. live on… the person is legally dead when the brain stops functioning. So yes, it will be a body transplay.
(I think it was another Gahan Wilson cartoon, the older couple talking to the brain floating n the tank - “We were wondering if you want us to sell the motorcycle?”)
There was also a SF story about this, a while ago, where the brain transplant worked, it seems to be the brain’s personality in the new body - then the doctor observes the patient making the sign of the cross backwards, Eastern Orthodox style - like the donor body used to, not the current brain’s standard procedure.
of course, there are more interesting situations; what if we can regenerate deteriorating brain with new brain cells grown from stem cells? What effect does this ahve on the personality? What if over time your personality and memory fades with the old cells, so you the 2,000 person don’t remember what happened 1,000 years ago? What’s the statute of limitations? What if we could cure behaviour like rape or murder by adding missing parts to the brain? Is the cured person with complete memory still legally responsible, or was that a disease and so not guilty by reason of mental defect?
For example, what is the legal status of a clone?
Is it a child of the source person who initiated the replication?
Or is it like an identical twin, legally a child of the source’s parents and entitled to a child’s share of the parents’ inheritance? Are the Source’s parents then obligated to provide child supporrt, be the legal guardian, or does the source person have that role?
Or since the source is effectively the complete set of parents of the clone, having initiated the life and being the source of both sets of chromosomes, should a clone get a double share of the source “parent’s” inheritance over regular children, who are half the source parent’s and half their partner’s?
I hope a lot of future judges have a serious science background. God knows there’s a lot of screwey decisions related to science and patents today…