As for the life-to-life comparison, I actually think my answer would be in the neighborhood of 100. More than 10. Less than 1000. I’d view public policy the same way: all things being equal, I’d be roughly indifferent between a policy that would prevent 10,000 miscarriages and one that would prevent 100 childhood deaths — this would be about what I would use in trying to efficiently allocate NIH resources. Far more than ten times as many people die (as fetuses) of miscarriage than of malaria, but I consider the latter a greater public health problem. I’d pay more to prevent a miscarriage than to prevent a broken arm. But less than I would pay to prevent a violent rape. There are plenty of behavioral experiments and studies one could do to check whether other humans (policy makers, parents, etc.) share my valuations. But I have some anecdotal evidence that I’m not too far out of the mainstream.

Can I derive my number from a set of incontrovertible axioms? Well, no. But I don’t think you can either. Here’s why your derivation is sketchy. I think there is a difference between value and potential value. If a fetus grows to maturity, its value will be greater to everyone (including its future self) than it is now. But when all you have is a bunch of cells — or just a boy and a girl and beautiful moon — well, you have potential life, potential value. And of course, the vast majority of potential value is never realized. More “possible worlds” are not realized—at least, we only get to witness one. Most possible existence never comes to exist. Most “might have beens” never are. But summing up all the excluded “might have beens” corresponding to every action is impossible and unproductive. (It reminds me of those crazy conundrums from philosophy class: “If you have the power to will an additional billion humans into existence and you don’t do it, are you worse than Hitler? Is God, therefore, worse than Hitler? What if, by willing a billion humans out of existence you could will an additional two billion into existence? Would you do that?”)

Explaining precisely why death is bad (and precisely when the “bad” occurs) has been a puzzle for philosophers for a long time. Quantifying losses from death is also difficult. I’m not going to claim to have solved this fundamental problem.

Religiously speaking, it’s even harder. It’s impossible to know how the extent to which any individual spirit will be better or worse off if a particular fetus dies. (Will the spirit go to another fetus? Or miss out on this life altogether? Will this be better or worse for the spirit in the long run?) Once all quantities are incalculable by mortals and potentially infinite, economic analysis becomes harder for most of us to do well. You can pray and ask God how to allocate funding between miscarriage prevention and malaria research, but if you don’t get an answer, you’ve got to think it through yourself.

So why is it that humans view a the loss of an infant that existed as more tragic than the loss of an infant that might have existed but didn’t? Not easy to answer philosophically. But it’s very clear that we feel and behave that way, and that we don’t want people who don’t feel this way running our country. Whether a lost one-gram fetus should be viewed as an “infant that existed” or an “infant that might have existed” is hard to argue with economics alone, but it’s clear that most people treat it as somewhere in the middle.

When I thought you were going to try to economically justify your five-to-one ratio, I was rather interested — I thought you might have a genuinely new idea for approaching a famous philosophical problem. But arguments for one-to-one are old hat, easy and usually silly. You just _declare_ that the value of the fetus (or a recently fertilized egg cell, or potentially fertilized egg cell, or potentially produced and subsequently potentially fertilized egg cell) is equal to the entire value of its potential future life to itself and all others and leave it at that. And with zero effort you have reached a conclusion that virtually nobody actually agrees with in practice.

Who knows the resumé of the unborn?

@131: The thought experiment doesn’t take into account the Mormon sentiment (doctrine or folk religion, you decide) that the spirit would simply be reassigned to another body — that man cannot ultimately thwart the will of God. Had Marilyn aborted Silus, then Peggy will have a chance to raise Zachary.

All: interesting discussion… my own thoughts on abortion run along what President Clinton is supposed to have said on the matter (and I’m paraphrasing): abortion should be safe, legal, and rare.

I wasn’t asking for you to evaluate societal loss. Just personal loss. How much of your lifetime net worth would you pay to be alive? There is very little sci-fi required for that. You say you’d pay alot, but then seem to reject the metric because it implies too high a value to a fetus. Well it sounds like you are working from conclusions backwards. That’s common, but it isn’t good practice.

Here’s an easier one. How much would you pay to not die next year? Is that less sci-fi for you? We should expect that people would value a whole life at least as much as the last X years of it. So that would be a useful lower bound. We can actually make guesses on that judging from people’s _behavior_ in risky situations.

Unfortunately, by the way, people are pretty bad at answering these questions. Which is why it would be nice to have some data on how they actually behave. Hence we look at data on how people act to preserve their own lives and how much money they spend to do so.

Your burning building example is too difficult to answer for almost any comparison. The imprecision makes it comical. Since you are so fond of the burning building example, tell me how many fetuses it would take for you to rescue them over an eight year old girl. 100? 1000? 10000? 10? I doubt you’ll answer :)

But the hypothetical is also pointless because the number we want is not how _I_ value those two lives, but how those two (or one hundred and one) people (or spirits) value their own lives (since societal welfare is an aggregation of individual welfare). You see, abortion is imposing an externality on the fetus, and that is the inefficiency we wish to correct. The 2-6 million number for people’s life evaluations is coming from people’s valuations of their own life based on their behavior, rather than asking people questions about rescuing a person vs. rescuing a briefcase full of money from a burning building — which is about how much other people _say_ they care about you.

You suggest $20,000 as a value of a fetus not being aborted as a reasonable approximation. I think you are vastly underestimating the value of that unborn child. But I don’t expect to change your mind. Abortion just doesn’t seem to be a topic that lends itself to people changing their minds.

Wow. I have to imagine the universe without my having been born and figure out how much worse that would be for me (whatever that means…) Despite having seen “It’s a Wonderful Life”, most of us do not much experience imagining ourselves not having been born. Retrospectively, I guess I’d pay a lot to make sure my parents had intercourse on the night I was conceived, but, generally speaking, I don’t think that preventing a night of intercourse is equivalent to taking a full-grown life, although my only experience thinking about this comes from having seen “Back to the Future”…

Look, I was trying to measure the way people actually think and feel about the relative valuations, for public health purposes. That’s why I was trying to compare apples to apples (one-gram-fetus stranger to an eight-year-old stranger, or a one-gram-fetus daughter to an eight-year-old daughter, or a one-gram-fetus son to a eight-cell-embryo son — lots of people have experience making life decisions on behalf of loved ones). And I was hoping that our resident economist could teach me something about that. Now it seems you are instead trying to do some utterly bizarre philosophical movie-plot gymnastics that can only lead to a one-one equivalence, which is simply not the way actual humans think and feel about the issue. That burning building is looking better and better… :)

How about practical, common ground approaches to combating infanticide? Obama has a public record of support for killing infants who survive abortions. That places him somewhere to the left of Chairman Mao. “Righteous wind” indeed.

Yes, Obama has a very liberal record on abortion, but (as many posts here have said in one way or another), you can be against abortions for convenience and still make the case that the decision should be up to a woman, her doctor, and her conscience. Still, for those of us that both really like Senator Obama and also wholeheartedly support the church’s position on abortion, his so-called ”extreme” stance on abortion is disconcerting, though he does have a record of supporting policies that help reduce abortions, like increasing access to affordable birth-control. How many abortions are the result of poor women making a poor choice, getting pregnant, then feeling abortion is the only way out of a hopeless situation?…So on abortion even, [Obama] represents an opportunity for moving forward that the tired pro-life/pro-choice paradigm just doesn’t offer (the either/or of that debate doesn’t get us anywhere folks). How might we move forward? By advancing policies that will reduce the demand for abortion. I think both ”sides” can agree to that, though I have seen no leadership by Republicans on this issue. They just want to ban the procedure, which ultimately does not solve the root problems at all.

I wish I could be as confident as you in supporting Obama, and I say this as someone who not only will be voting for him tomorrow, but as someone who thinks there is a lot of wisdom to what you say about his potential to lead America in the direction of a practical, common ground approaches to combating abortion. But I remain conflicted, because I strongly suspect that the counsel we have received from our church leaders does not allow for this conclusion. Not that I imagine all general authorities think alike when it comes to voting for president, or that they all intend their statements on abortion to be taken as literal voting guides; and moreover, even if such were the case, it wouldn’t necessarily command my vote. But voting for sucha clearly pro-choice candidate, and trying to convince myself on basis of his random comments that there is a real alternative there, does trouble me–a whole lot more than I expected it to, now that it comes down to it.

More here, if you’re interested.