The doctor has already used up a lot of his potential. But the baby has almost no potential. Well, that's not entirely clear... Let me be more specific: the

The doctor has already used up a lot of his potential. But the baby has almost no potential. Well, that's not entirely clear... Let me be more specific: the baby has some potential, but since it's too young, we don't know where on the Bell curve of potential it lies. Our change in expected value by throwing the baby overboard and making a brand new one is zero (at least once we casually discard the mother's grief, and the general distaste for throwing babies to sharks :) ). We have to evaluate this against throwing the doctor overboard and starting with a fresh baby - the doctor has already proven that he's somewhere near the top of the Bell curve, so in order to figure out the utility of that trade, we need to consider how much he's likely to accomplish over the rest of his life as compared to what an average baby will accomplish during theirs. Perhaps making the doctor 50 years old was a bit much, as it does raise questions about how much life he actually has left, and whether the (say) 20 years that he'll actually be practicing can be considered as useful as the 80 years the newborn has in front of it. I think there's still an argument to be made that 20 years of work from a highly qualified researcher is worth "more" than an average lifetime lived by an average person, but it's not crystal clear. Suppose I'd made the doctor a brilliant 25 year old making great strides in cancer research - would that make a difference to you?