Friday, May 12, 2006

Deontology Meets the Mere Addition Paradox

One objection to utilitarianism is its difficulty in dealing with questions of population change. For example, is it desirable to add more people to a population if the new additions have lives that are (a) worth living but (b) not quite as good as the lives of those already living? The larger population would have higher total utility but lower average utility. (Set aside concerns about negative externalities from population growth. Holding the happiness of the already-living sharpens the philosophical question.)

Derek Parfit’s “Mere Addition Paradox” (MAP) shows how both total and average utilitarianism can lead to bizarre and (seemingly) unpalatable conclusions. This article by Kai Chan has the best explanation of the MAP I’ve found, all in the first three pages. Here’s my quickie explanation: Suppose you have an existing population with relatively high utility. Someone proposes an addition like that described above (new people with lives that are worth living but below the previous average). Should we favor the proposal? The obvious answer seems to be “yes,” or at least “there’s no reason not to.” Adopting average rather than total utilitarianism could allow you to resist this conclusion – but that’s precisely what’s bizarre about average utilitarianism. So the new group is added on. Once those people are in existence, someone proposes a slight redistribution of resources that will make the new people better off and the old people worse off, with an overall net positive result (the utility gains exceed the utility losses). This proposal, too, is difficult to resist. But now consider the addition of yet another group of new people, with lives worth living but less satisfying than the lives of those who already exist. Repeat until you have a very large population of people with lives barely worth living. This is what Parfit calls the “repugnant conclusion.”

Now, what I’m wondering is whether an analytically similar problem might afflict some deontologists (e.g., natural rights theorists) who think they’ve managed to dodge the problems of utilitarianism. Say you have a population of people whose rights are respected perfectly. And suppose the population could be increased through the addition of a new group of people whose rights are mostly respected, albeit with the occasional violation. On what grounds could the deontologist resist the addition of this group? These people would, presumably, prefer to live despite the occasional rights violation. And in any case, if the deontologist believes in a right of procreation (or opposes any intervention to stop procreation), then he would have to allow the entrance of the new group.

Next step: Once we have the larger population, suppose we have the opportunity, via some change in policy, to redistribute the rights violations so that the new group has fewer rights violation, the older group has more, and the total number and severity of rights violations has fallen. Now, here the deontologist might object: right violations are not interpersonally comparable. The lesser violation of the rights of some does not compensate for the greater violations of the rights of others. But I don’t think this position will withstand scrutiny. The deontologist would have to resist changes in enforcement policy that would, say, prevent 1000 forcible rapes while allowing one more act of shoplifting. Or, at a minimum, he would have to shrug his shoulders. Similarly, the deontologists would have to resist (or at least be indifferent to) any change in the form of government that would result in lesser protection of any person’s rights. In practice, I don’t believe deontologists actually think that way. (Notice, for example, the many deontologist anarcho-capitalists who favor abolishing the state in favor of private protection agencies, even though such a change would assuredly cause some people’s rights to be better protected while at least a few others’ rights suffered.) So I think that reasonable deontologists would have to accept the proposed redistribution in rights protection.

Now repeat the process. The endpoint will be a society with the maximum number of people that could be sustained at some minimal level of rights protection.

The problem, for both utilitarians and deontologists, results from an intransitivity driven by the distinction between actual and potential persons. For both groups, it seems strange to regard non-existent people as having morally relevant interests (for the utilitarians) or inherent moral rights (for the deontologists). Yet once such people do exist, their interests and/or rights suddenly matter. For utilitarians, that means weighing their interests against those of other real people. For deontologists, it means respecting and protecting their rights. That might seem to require no sacrifice of the rights of others – until we recognize that rights protection is costly, and therefore we can’t avoid trade-offs in rights protection. Within a given regime, the trade-off is felt in the allocation of law enforcement resources. Across regimes, the trade-off is felt in the choice of which regime to favor. To make the problem yet more vexing, the people who exist under each regime will differ (because, at a minimum, sensitive dependence on initial conditions means that different sperm will meet different ova).

For related thoughts about deontology versus consequentialism, see my post on lexicographic orderings.


Jadagul said...

Offhand, it seems like your deontology critique fails at the first step. Not everyone agrees, of course, but I don't think we have a moral obligation to create more people. Nor do I think we have a moral obligation to create fewer people (or go around offing the ones already here).

The paradox in MAP seems to come from the fact that at each step you have an affirmative duty to take the next step. Whereas, if I were arguing for the deontological position I'd just say that there's no best number of people; we should just try to observe and protect the rights of whoever exists. So the deontologist is only faced with the possibility that as population on its own goes to infinity, it gets harder to protect all rights and uphold all obligations; the utilitarian is faced with an apparent moral imperative to get to that point.

Glen Whitman said...

Jadagul -- Whether utilitarians are forced to take each step depends on whether they support total utilitarianism, average utilitarianism, or some kind of compromise position. But for my application of the argument to deontologists, I'm relying on an indifference relation: the deontologist cannot say that the addition of people is any worse. It might even be morally required if he supports rights of procreation or immigration. But indifference is enough to get us past that step of the argument. If B is at least as good as A, and C is strictly better than B, then C is strictly better than A.

"Whereas, if I were arguing for the deontological position I'd just say that there's no best number of people; we should just try to observe and protect the rights of whoever exists." Saying there's no best number of people is tantamount to claiming indifference about the number of people, so the argument goes through.

Richard Y Chappell said...

Interesting argument. I'd just like to point out that the original paradox isn't really anything to do with utilitarianism (the moral theory). It's a paradox for welfarist value theory, i.e. judgments of what consequences are "good" ("better", "worse", etc.), not what is right. A deontologist holds that there are moral side-constraints on the pursuit of these good consequences. They shouldn't deny that we can evaluate consequences as being "better" or "worse", even if they think it would be wrong for one to bring about the better result through rights-violating actions.

So all moral theorists are on an equal footing with regard to the MAP. They must all have some kind of value theory (assuming they recognize any duties or virtues of beneficence), and then the MAP comes in.

(R.M. Hare made some similar points, in sections I quote here.)

Admittedly, I've been assuming that everyone (no matter their moral theory) would accept a welfarist value theory. Perhaps someone might want to deny this, and instead adopt a rights-fetishizing value theory, whereby the "best" end result is that with the fewest rights-violations, no matter how poorly off the people are. That position seems awfully unmotivated to me, but if someone were to hold it, then your revised paradox could come into play.

Jadagul said...

I think Richard and I were, in part, trying to make the same point, although he did it much better. The fact that it's possible to move to a really bad situation without violating anyone's rights shouldn't come as a surprise to any deontologist (consider the circumstance where everyone volunatarily destroys all his property and mutilates himself. At least under certain strands of deontology, that's not a violation of anyone's rights, per se, but it is phenomenally stupid and leads to horrible consequences). You're acting as if a deontologist says "A is better than B iff there are fewer rights violations in A than in B," which I think is innacurate.

On reflection, I think situations like the MAP are the reason rights exist. I'm fundamentally a consequentialist (and a selfish consequentialist at that); I think that people have rights because that's the only way society can function well (and I respect rights because it makes me better of to respect rights than to ignore them). The MAP seems to be what happens when you follow 'naive utilitarianism': you try to increase welfare by a greedy algorithm, in a sense, without any concern for the potential long-term consequences. Institutionalized rights are the constraints on your welfare-maximization algorithm that keep it from derailing horribly, as it does here.

Glen Whitman said...

Jadagul -- I'm not sure you and Richard are saying the same thing. As I understand it, Richard is saying that everyone (utilitarian or not) must face the MAP if they have a welfarist value theory; it just so happens that deontologists don't let their value theory determine their moral theory. You, on the other hand, seem to be saying that deontologists are immune to the MAP.

In any case, I agree with your general perspective on rights and utility: rights are a convenient social convention for maximizing utility. Naive attempts to maximize utility directly would, paradoxically, lead to lower utility. That said, I don't think this position allows us to dodge the MAP. Why? Because if we're going to say, "X [e.g., rights] will maximize utility," we'd darn well better say what we think we're maximizing. Is it the average, the total, or something else? The answer will affect what kinds of rights we think have the best results, since what we deem "best" depends on the standard of value.

David Friedman said...

For an approach to the utilitarian problem, you might want to look at an old piece of mine:

"What Does Optimum Population Mean?" Research in Population Economics, Vol. III (1981), Eds. Simon and Lindert.

I propose a criterion that produces a partial ordering--a way of saying that some larger population futures are superior to some smaller, some smaller to some larger, and some pairs are incomparable.

Genius said...

I’m with maybev on this,
1) We are to a large extent operating under a misconception of what "a life worth living" is.

To put it simply you could sit there watching the world get better with each new lovely baby entering the world the world getting better each time - eventually you stop because the next baby makes the world marginally worse but by that stage the world is HUGELY better than the world now.
(the paradox implies you can keep adding only positive numbers and end up with a negitive total! obviously nonsense).

Also the paradox doesn’t occur like that in practice because you have to consider the sustainability of the model. (Another thing we intuitively include in our analysis).
For example environmentalists tell us that the world may be overpopulated - if that is the case the utilitarian may well want us to REDUCE our population even from the current level just to ensure that the planet can maintain a reasonable number of people in the status of a life worth living into the future as far as the mind can see.
these and a couple of other factors (like the investment to make a human) prop up the standard of hte lowest peopel in the optimal utilitarian world.

Genius said...

In fact, In the end, very very long run utilitarian objectives would totally dominate questions of whether we had one additional person now or not right now anyway.

I'm sure you can imagine a couple of them.

Just to cover my bases...
If you are not looking into the future then in the instantanious timeframe infinity lives are as good as any other because people don't consume any finite amount of resources over an instant (so you dont run out!).

unenlightened said...

Ethics is usually an attempt to make our vices into virtues, and measure the unmeasureable. What (for heaven's sake?) is the utility of existence? Did the rings of Saturn only become beautiful when we invented telescopes? Obsession with the satisfaction of desire, whether pursued collectively or competitively is no morality at all - it's economics and immorality. Perhaps we should minimise the total (or average) unhappiness instead by blowing up the planet. Perhaps we will, but the philosophy stinks, and the calculation is ridiculous. Cheers, bob.