> But the question in a hypothetical sense does seem quite valid and hard.
I appreciate this sentiment, and tend to think likewise. However, the situation is a hypothetical. In the end, perhaps most important is the practical decisions we make, which is almost never situations like the ones you describe above, but more like "what cause should I donate to"? In that sense, it might be hard to discern between different causes in the Givewell top lists, but picking either of those at random is probably a good heuristic that already beats a fairly widespread heuristic of just giving to something like Make-A-Wish, if you're starting from the point of donating €x to a charity.
I appreciate this sentiment, and tend to think likewise. However, the situation is a hypothetical. In the end, perhaps most important is the practical decisions we make, which is almost never situations like the ones you describe above, but more like "what cause should I donate to"? In that sense, it might be hard to discern between different causes in the Givewell top lists, but picking either of those at random is probably a good heuristic that already beats a fairly widespread heuristic of just giving to something like Make-A-Wish, if you're starting from the point of donating €x to a charity.