A society which would allow such a binary situation as shown in this thought experiment should have a revolt in which such inhumane decisions are not required.
If the thought experient is designed to determine “what do each of us value more in a human being”, you *could* just ask that.
I do not know enough about their families. I do not know enough about their roles in society beyond what was presented here. Perhaps the religious extremist also has a job in which he has a large family to support and one of those in his family will do far greater things than the cosmologist.
Perhaps the cosmologist will die at the age of 61 regardless of treatment.
The same can be said in the opposite direction.
In short, not enough information here to decide with.
But if I had to: I would ask them. They know themselves best. Can they not speak for themselves?
You’re right of course This kind of thing is “mind candy” and a “friend sorter”. “What’s your favorite color?” “Do you like gum?” “Would you willingly kill a human being based on a thought experiment? If so, which one and why?”
Be careful: The cosmologist might have a friend who is experimenting with a gravity wave machine and will create an artificial gravity bubble in the basement underneath where you’re standing and skew it in his favor