UPDATE: I think Mike Almeida is right. The response I lay out won’t work.
Suppose you have the option of saving a drowning child. Further suppose that Lewisian Modal Realism is true. Here are your options.
SAVE THE CHILD
You save the child. However, consider what is true about the pluriverse if you save the child. If you save the child, then there is a concrete world very much like this one up to the point of you saving the child where a counterpart of you let’s the child drown.LET THE CHILD DROWN
You let the child drown. However, consider what is true about the pluriverse if you let the child drown. If you let the child drown, then there is a concrete world very much like this one up to the point of you letting the child drown where a counterpart of you saves the child.
Notice that it seems to turn out that the sum total of children saved from drowning will be the exact same in the pluriverse whether you save the child in the actual world or not.
Lewis discusses this odd consequence in On the Plurality of Worlds (pp. 123-128). Here’s one way to frame all of this as an argument against modal realism.
The Moral Argument Against Modal Realism
- If Modal Realism is true, then the sum total of children saved in the pluriverse is the same whether you save the child or not.
- If the sum total of children saved in the pluriverse is the same whether you save the child or not, then it is morally permissible to let the child drown.
- Therefore, if modal realism is true, then it is morally permissible to let the child drown.
- It is not morally permissible to let the child drown.
- Therefore, modal realism is not true.
This is just one candidate way to extract the argument that Lewis discusses. For example, he notes there is a prudential version of the argument (p. 124). Let’s go with the moral version. What I want to say on Lewis’ behalf will work equally well for either version.
Lewis’ main response to the moral version of the argument seems to be to reject (2) by rejecting what he calls “pure utilitarianism” (p. 127). However, I’m surprised that Lewis didn’t take a different strategy (or at least throw it out there as a potential option).
Fast forward to the next chapter where Lewis criticizes Linguistic, Pictorial, and Magical Ersatzism. One of his main complaints with at least Linguistic Ersatzism and Pictorial Ersatzism is that they (according to Lewis) rule out the possibility of indiscernable worlds.
I take it that Lewis thinks that there are at least as many concrete worlds for every way this world could have been, but for all we know there could be a few extra. There may be, for all we know, a world that is completely indiscernable from this one. Everything that happens in this world happens in some other world that is indiscernable from this one.
If concrete modal realism doesn’t rule this out, then we shouldn’t accept (1). Modal realism (by itself) doesn’t guarantee that the sum total children saved in the universe will be the same whether you save the child or not. If you’re in one of these extra worlds, then your actions really have a determinate impact on the total number of children saved in the pluriverse.
If you’re in one of these extra worlds, then your actions really have a determinate impact on the total number of children saved in the pluriverse.
I’m pretty sure that’s not true, Andrew. The reason is that the number saved is certainly infinitely large. One more or less does not affect the number saved. But that aside, it really doesn’t matter to this moral argument how many extra (indiscernible) worlds there are. No matter what you do, you cannot add or subtract from the number of children saved in logical space; that’s just impossible. All you can do is choose which world to actualize. So think of it this way. Lay out all of the worlds there are on a board. On that board we have all of the worlds in which children that are saved and all of the worlds in which they are not. Now supposed your asked to move one of the worlds close to you. You get to pick. No matter which one you move close to yourself, the board is the same. You’ve just moved some pieces around.
That’s pretty much all we can do.
Heller has a paper on exactly this objection to Modal Realism. You should check it out.
“The Immorality of Modal Realism, Or: How I Learned to Stop Worrying and Let the Children Drown”
Mark. Thanks for the paper link. I actually have read it, and I think it’s awesome.
Mike. You’re absolutely right. This response won’t work.
“No matter what you do, you cannot add or subtract from the number of children saved in logical space; that’s just impossible. ”
Why think this? I thought Andrew’s point was that this claim about the static, unchangeable nature of the pluriverse as a whole is a further claim that goes beyond the minimal claim that there’s at least one concrete world for each way a world could be.
In other words, where’s the contradiction in the following picture: every possibility obtains once, and then there’s one extra concrete world in addition (which might end up duplicating any one of the other worlds). We are in the extra world, and our choices influence which way it ends up. Hence — on this view — our choices affect the total number of lives saved in the pluriverse (modulo complications involving infinities), and is not just a matter of self-location or shifting the pieces around.
I can’t see how this is a valid argument. We all know someone letting child drown is possible. According to modal realism, all such possibilities are realized. But I really do not see how you go from say it’s possible and thus in some worlds actual to saying that it’s morally permissible? I mean, I can see how you might buy the moral claim, but nonetheless it certainly does NOT logically follow. We do not judge the the moral permissibility of an action by toting up the total number of times it occurs versus the times it does not occur. We judge whether an action is morally permissible simply by that person’s intention. That’s why planning or attempting to murder someone is wrong, even if you never actually do so. If modal realism is true, saving a drowning child child does not increase the global number of saved children, and in some possible worlds you let the child drown. But how does this change the permissibility of letting children drown?? His argument is that if modal realism is true then radical moral nihilism must be true, and since it isn’t, modal realism must be wrong; this is simply not logically sound. I’m surprised he presents this as a serious argument. He might as well had said that (1)if modal realism is true then being broke must not be bad because in some possible worlds you aren’t broke, (2)and since we know being broke is bad, modal realism must be false. Even if we accept (1), which is obviously silly, the fact that (2) contradicts (1) is completely irrelevant. Can you see what I mean?
Sorry, I meant (2) and since we know being broke is bad, (3) modal realism must be false. Otherwise (2) and the conclusion are not separated, or at least you might think so, in which case my argument wouldn’t make sense.
Hi Matthew,
The argument is logically valid. It is impossible for the premises to be true while the conclusion is false.
(I’m on the road right now….I’ll get back to some of your other concerns when I get the chance today)
I accept that if the premises are true then the conclusion is true. Sorry, I was just trying to say that the argument was not rationally sound. I (incorrectly) used the colloquial sense of logical.
Anyhow, nonetheless, it seems to me that you could still accept the premises a”true”, but not the conclusion, by simply not taking them at face value. I mean, think the moral nihilist could say everything is moral permissible, but still accept that “some things are not morally permissible” by simply taking it to be a fact about how society operates or what have you. This doesn’t make the argument logically invalid though, like you said. Am I making sense?
Hi Matthew,
I finally settled in to our first destination.
Regarding the validity stuff – I thought that’s what you probably meant – just wanted to make sure.
One other point of clarification. We should be clear that Lewis agrees with you. He thinks this is a bad argument…he also seems to think it’s bad for much the same reasons you do (that is he thinks only some version of utilitarianism that ignored intentions would be able to get this argument of the ground)
That said…doesn’t it seem like it’s worth taking seriously given that a lot of people have argued (and very well I might add) for the sort of utilitarianism that would motivate one of the crucial premises of the argument? Here I’m just defending the idea that we should take it seriously. One of the major problems for this kind of utilitarianism is that it seems to ignore the role that intnentions play in moral evaluations, but utilitarians have come up with good things to say here. For example, some make the distinction between rightness and wrongness on one hand and blameworthy and praiseworthy on the other.
You have some other points here. I’m going to think more about them.
You know what? Now that I think about it…the most plausible versions of act utilitarianism make use of the distinction I mentioned in my last comment between right and wrong on one hand and praiseworthy and blameworthy on the other…those versions can probably make the same sort of moves that have already been discussed here…they can say that there is something wrong with persons who don’t save children at the level of praise/blame even if the action is permissible because of the way the numbers pan out.
Hm, I see your point. I guess I just thought that the claim that letting children drowning is even possibly permissible is obviously false, even if from a bird’s eye view it makes no difference (I suppose I didn’t think about that). But your defense of utilitarianism makes sense, I think. Thanks for responding^_^.
You know what, I found an interesting article related to this issue. It’s Infinite Ethics on nickbostrom.com. You ought to read it.
I see that you’re not going to respond. Dang. Here, please search this if read this some time, http://www.nickbostrom.com/ethics/infinite.pdf. Seriously, it is very relevant to this issue and it’s interesting. Eh, oh well.
Hey Matthew,
It’s been a busy few days, and I haven’t had a chance to read what you suggested.
I’ll check it out when I get a chance.
Man, busy are you? I guess philosophy teachers must get a lot of work. Sounds hard anyway. Anyhow, how sure are you that act utilitarianism is correct? It can make some crazy recommendations. Like involuntary pleasure comas. Might need some work or something. But I don’t know.
Not sure that it’s true at all. I’ve never maintained that it’s true. Earlier in this thread, I just wanted to highlight we shouldn’t say that an argument is ridiculous (and not worth our attention) merely because it assumes the truth of act utlitarianism.
I myself don’t think that act utilitarianism is true. Originally, in the post I was trying to offer Lewis a better way to respond to the argument than merely rejecting act utilitarianism because act utilitarians have pretty sophisticated defenses of their view (like I mentioned in the comment thread) that make the view seem less ridiculous than one might initially think it is.
Oh, I see. So that’s what you meant. Sophisticated huh? Hmm. Do you think most positions have sophisticated arguments? Should that usually be true, or am I wrong? So basically, requires a lot of thought. But if you read the paper I suggested, it makes the point that utilitarianism (and many other popular moral theories) break down if the universe is infinite, which is empirically likely. So he basically says if the theory says (pending on our latest cosmological data) that it might be okay to do whatever you want, then it ought be rejected (and even the most hardened supporters would not accept this). He suggests some revisions to avoid this problem. What do you think?
Excellent. There’s a guy in the department here who was just talking about this objection to Utilitarianism the other day.