My favourite arguments against person-affecting views

1. Introduction

According to person-affecting views (PAVs) in population ethics, adding happy people to the world is morally neutral. It’s neither good nor bad.

Are PAVs true? The question is important.

If PAVs are true, then the EA community is likely spending way too much time and money on reducing x-risk. After all, a supposed major benefit of reducing x-risk is that it increases the chance that lots of happy people come into existence. If PAVs are true, this ‘benefit’ is no benefit at all.

By contrast, if PAVs are false, then the EA community (and the world at large) is likely spending way too little time and money on reducing x-risk. After all, the future could contain a lot of happy people. So if adding happy people to the world is good, reducing x-risk is plausibly very good.

And if PAVs are false, it’s plausibly very important to ensure that people believe that PAVs are false. In spreading this belief, we reduce the risk of the following non-extinction failure-mode: humanity successfully navigates the transition to advanced AI but then creates way too few happy people.

So it’s important to figure out whether PAVs are true or false. The EA community has made efforts on this front, but the best-known arguments leave something to be desired. In particular, the arguments against PAVs mostly only apply to specific versions of these views.[1] Many other PAVs remain untouched.

Nevertheless, I think there are strong arguments against PAVs in general. In this post, I sketch out some of my favourites.

2. The simple argument

Before we begin, a quick terminological note. In this post, I use ‘happy people’ as shorthand for ‘people whose lives are good overall’ and ‘miserable people’ as shorthand for ‘people whose lives are bad overall.’

With that out the way, let’s start with a simple argument:

The simple argument

1. Some things are good (for example: happiness, love, friendship, beauty, achievement, knowledge, and virtue).

2. By creating happy people, we can bring more of these good things into the world.

3. And the more good things, the better.

C1. Therefore, creating happy people can be good

C2. Therefore, PAVs are false.

2.1. The classic PAV response

Advocates of PAVs reject this simple argument. The classic PAV response begins with the following two claims:[2]

The Person-Affecting Restriction

One outcome can’t be better than another unless it’s better for some person.

Existence Anticomparativism

Existing can’t be better or worse for a person than not-existing.

Each of these two claims seems tough to deny. Consider first the Person-Affecting Restriction. How could one outcome be better than another if it’s not better for anyone? Now consider Existence Anticomparativism. If existing could be better for a person than not-existing, then it seemingly must be that not-existing would be worse for that person than existing. But how can anything be better or worse for a person that doesn’t exist?[3]

So each of the two claims seems plausible, and they together imply that premise 3 of the simple argument is false: sometimes, bringing more good things into the world doesn’t make the world better. Here’s why. By creating a happy person, we bring more good things into the world. But our action isn’t better for this happy person (by Existence Anticomparativism), nor is it better for anyone else (by stipulation), and so it isn’t better for the world (by the Person-Affecting Restriction).

By reasoning in this way, advocates of PAVs can defuse the simple argument and defend their claim that creating happy people isn’t good.

2.2. The problem with the classic PAV response

Now for the problem. The Person-Affecting Restriction and Existence Anticomparativism don’t just together imply that creating happy people isn’t good. They also together imply that:

(a) Creating miserable people isn’t bad.

(b) Creating barely happy people isn’t worse than creating different, very happy people.[4]

Here’s why the Person-Affecting Restriction and Existence Anticomparativism together imply (a). Suppose that we create a miserable person. Our action isn’t worse for this miserable person (by Existence Anticomparativism), nor is it worse for anyone else (by stipulation), and so it isn’t worse for the world (by the Person-Affecting Restriction). So creating miserable people isn’t bad.

And here’s why the Person-Affecting Restriction and Existence Anticomparativism together imply (b). Suppose we have a choice between (i) creating a set of barely happy people, and (ii) creating an entirely different set of very happy people. Suppose that we create the barely happy people. Our action isn’t worse for the very happy people (by Existence Anticomparativism), nor is it worse for anyone else (by stipulation), and so it isn’t worse for the world (by the Person-Affecting Restriction). So creating barely happy people isn’t worse than creating different, very happy people.

But each of (a) and (b) seems false. It certainly seems like creating miserable people is bad, and that creating barely happy people is worse than creating different, very happy people. And that suggests that at least one of our premises is false: either the Person-Affecting Restriction or Existence Anticomparativism. Although these claims each seemed appealing at first, they together imply some very counterintuitive conclusions, so at least one of them must be incorrect.

And if at least one of these claims is incorrect, then the classic PAV response to the simple argument is undercut. After all, the classic response uses both the Person-Affecting Restriction and Existence Anticomparativism to object to premise 3 of the simple argument. If at least one of those claims is incorrect, then the objection to premise 3 no longer works, and so premise 3 (‘the more good things, the better’) is back to looking pretty compelling. And since premises 1 and 2 are hard to doubt, the simple argument as a whole is back to looking pretty compelling.

How might advocates of PAVs respond now? They could modify Existence Anticomparativism. The original claim is: ‘Existing can’t be better or worse for a person than not existing.’ Advocates of PAVs could replace it with ‘Existing can’t be better or worse for a person than not existing.’ Then Existence Anticomparativism and the Person-Affecting Restriction would no longer together imply that creating miserable people isn’t bad. But if advocates of PAVs make this response, then they’ll have to find some way to explain the resulting asymmetry: if existing can’t be better for a person than not existing, why can it be worse?[5]

And in any case, modifying Existence Anticomparativism doesn’t help PAVs avoid the other counterintuitive conclusion: creating barely happy people isn’t worse than creating different, very happy people. Advocates of PAVs will have to find some other way of dealing with that. This other counterintuitive conclusion is the famous non-identity problem for PAVs, and I’ll discuss it more below. Before that, let’s consider another argument against PAVs.

3. Tomi’s argument that creating happy people is good

This argument comes from my colleague Tomi Francis.[6] Suppose that a hundred people already exist. You’re considering creating ten billion extra people. You have three options: A, B, and C. In A, the hundred already-existing people have welfare level 40, and only they exist. In B, the hundred already-existing people have welfare level 41, and the ten billion extra people also have welfare level 41. In C, the hundred already-existing people have welfare level 40, and the ten billion extra people have welfare level 60.

One hundred peopleTen billion different people
A40-
B4141
C40100

Here’s the argument. B is better than A, because B is better than A for the hundred already-existing people, and the ten billion extra people all have happy lives. And C is better than B, because moving to C makes a hundred people’s lives slightly worse and ten billion people’s lives much better. And betterness is transitive: if an outcome X is better than an outcome Y, and Y is better than an outcome Z, then X is better than Z. So since C is better than B, and B is better than A, C is better than A. And C and A are identical except for the extra ten billion people living happy lives in C. Therefore, it’s good to add happy people, and hence PAVs are false.

Tomi’s argument presents a new challenge to PAVs. The argument doesn’t employ any premise like ‘The more good things, the better,’ and so it can’t be defused by the Person-Affecting Restriction and Existence Anticomparativism.

3.1. A PAV response

How might advocates of PAVs respond to Tomi’s argument? One possibility is to claim that betterness is option-set dependent: whether an outcome X is better than an outcome Y can depend on what other outcomes are available as options to choose. In particular, advocates of PAVs could claim:

  • B is better than A when B and A are the only options

  • B is not better than A when C is also an option.

And advocates of PAVs could defend the second bullet-point in the following way: when C is available, B harms (or is unjust to) the ten billion extra people, because these extra people are better off in C.[7] And this harm/​injustice prevents B from being better than A.

3.2. A problem with the PAV response

That’s a possible response. I don’t think it’s especially convincing. Choosing B doesn’t seem especially unjust to the ten billion extra people, given that they enjoy the same good welfare level as everyone else. Certainly, it doesn’t seem like the kind of injustice that should lead us to choose A instead, thereby not creating the extra people at all and making the already-existing people worse off.

And choosing B harms the extra ten billion people only in a technical sense of the word, according to which a person is harmed if and only if this person is worse off than they could have been. But this technical sense of the word ‘harm’ differs significantly from our ordinary sense of the word, as is made clear by the following example. Suppose I could give a total stranger £0, £10 or £11. In the technical sense, I’d harm this stranger if I gave them £10, since I leave them worse off than they could have been. But I needn’t be harming them in the ordinary sense, and the same goes for the ten billion extra people in B. Their lives at welfare level 41 could be lives of moderate happiness, with little suffering.

In sum, I think Tomi’s argument presents a real challenge to PAVs.

4. The non-identity problem

Now let’s get back to the non-identity problem. Here’s a recap of how that goes. If the Person-Affecting Restriction and Existence Anticomparativism are both true, then creating a barely happy person is not worse than creating a different, very happy person. That conclusion seems implausible, and so casts doubt on the premises. How might advocates of PAVs respond?

One response is to bite the bullet. Advocates of PAVs can embrace the implausible-seeming conclusion, and thereby hold on to the Person-Affecting Restriction and Existence Anticomparativism. But that’s not as straightforward as it seems, because here’s another, independent argument from Tomi against the implausible-seeming conclusion.

4.1. Tomi’s argument that creating happier people is better

Suppose that Adam already exists. You’re considering creating Eve or Steve. You have three options: D, E, and F. In D, Adam has welfare level 99 and Eve will be created with welfare level 100. In E, Adam has welfare level 100 and Eve will be created with welfare level 99. In F, Adam has welfare level 99 and Steve will be created with welfare level 1.

AdamEveSteve
D99100-
E10099-
F99-1

Here’s the argument. D is equally good as E, because D and E just swap Adam’s and Eve’s welfare levels, and Adam and Eve are equally morally important. And E is better than F, because E is better for Adam, and it replaces worse-off Steve with better-off Eve. And betterness is transitive in the relevant sense: D is equally good as E, and E is better than F, so D is better than F. And Adam’s welfare level is the same in D as in F; the only difference is that D replaces worse-off Steve with better-off Eve. So creating a very happy person is better than creating a different, barely happy person. Since the combination of the Person-Affecting Restriction and Existence Anticomparativism implies the contrary, at least one of these latter two claims must be false.

4.1.1. A PAV response

So advocates of PAVs can’t just bite the bullet on the non-identity problem. They also have to reckon with Tomi’s argument. How might they do that?

One possibility is to shift gears. So far, we’ve been arguing about the axiological facts: facts about what’s good and bad, better and worse. But advocates of PAVs can claim that it’s the deontic facts that are central to morality: facts about what’s morally permissible and morally required. This shift in gears gives PAVs a little more room to manoeuvre, since one might well think that we’re not always morally required to do what’s best. In particular, PAVs could concede that creating better-off Eve is better than creating worse-off Steve, but nevertheless maintain that we’re morally permitted to create worse-off Steve. Or PAVs could concede that creating happy people is good, but nevertheless maintain that we’re morally permitted not to create them (in cases where all else is equal). Now let’s consider these views.

5. Deontic PAVs

At the start of this post I wrote that, according to person-affecting views (PAVs), adding happy people to the world is neither good nor bad. I can now be more precise and call these ‘axiological PAVs’. Related but distinct are deontic PAVs, which say that (in cases where all else is equal) we’re morally permitted but not required to add happy people to the world. As I noted above, retreating to purely deontic PAVs offers a means of escape from some of the arguments of the previous sections.

But there are other arguments that tell against deontic PAVs. To explain these arguments, let’s first distinguish between two kinds of deontic PAV. Consider the following case:

One-Shot Non-Identity

(1) Amy 1

(2) Bobby 100

Here option (1) is creating Amy with a barely good life at welfare level 1. Option (2) is creating Bobby with a wonderful life at welfare level 100. The first kind of deontic PAV – a narrow view – says that each option is permissible. We’re morally permitted to create the person with the worse life.[8] The second kind of deontic PAV – a wide view – says that only (2) is permissible. We’re morally required to create the person with the better life.[9]

I’ll sketch out arguments against each of these views in turn. This paper presents the arguments in more detail.

5.1. A trilemma for narrow views

Here’s a problem for narrow views. Consider:

Expanded Non-Identity

(1) Amy 1

(2) Bobby 100

(3) Amy 10, Bobby 10

Here we’ve added a third option to One-Shot Non-Identity. The first two options are as before: create Amy with a barely good life at welfare level 1 or create Bobby with a wonderful life at welfare level 100. The new third option is to create both Amy and Bobby with mediocre lives at welfare level 10.

Narrow views imply that each of (1) and (2) are permissible when these are the only available options. What should they say when (3) is also an option? I’ll argue that they must say at least one of three implausible things, so that narrow views face a trilemma.

Option (1) remains permissible

The first thing they could say is that option (1) – creating Amy with a barely good life at welfare level 1 – remains permissible when we move from One-Shot Non-Identity to Expanded Non-Identity. But that claim implies:

Permissible to Choose Dominated Options

There are option sets in which we’re permitted to choose some option X even though there’s some other available option Y such that (i) everyone in X is better off in Y, (ii) everyone who exists in Y but not X has a good life, and (iii) Y is perfectly equal.

That’s because (1) is dominated by (3): (3) creates only people with good lives, it leads to perfect equality, and it’s better than (1) for Amy: the only person who exists in (1). It thus seems implausible that (1) is permissible.

Option (3) is permissible

Here’s something else that narrow views could say about Expanded Non-Identity: option (3) – creating Amy and Bobby with mediocre lives at welfare level 10 – is permissible. But that claim implies:

Permissible to Prioritise Creating Mediocre Lives:

There are option sets in which we’re permitted to choose some option X even though there’s some other available option Y such that X is much worse for the only person in Y and mediocre for the only person in X but not Y.

That’s because (3) is mediocre for Amy and much worse than (2) for Bobby: Bobby’s welfare level is 100 in (2) and 10 in (3). And we can imagine variations on Expanded Non-Identity in which Bobby’s welfare level in (2) is arbitrarily high. The higher Bobby’s welfare level in (2), the more implausible it is to claim that we’re permitted to choose (3).

Only option (2) is permissible

Now we can complete the trilemma for narrow views. If neither of (1) and (3) is permissible in Expanded Non-Identity, it must be that only (2) is permissible. But if only (2) is permissible, then narrow views imply:

Losers Can Dislodge Winners:

Adding some option X to an option set can make it wrong to choose a previously-permissible option Y, even though choosing X is itself wrong in the resulting option set.[10]

That’s because narrow views imply that each of (1) and (2) is permissible in One-Shot Non-Identity. So if only (2) is permissible in Expanded Non-Identity, then adding (3) to our option set has made it wrong to choose (1) even though choosing (3) is itself wrong in Expanded Non-Identity.

That’s a peculiar implication. It’s a deontic version of an old anecdote about the philosopher Sidney Morgenbesser. Here’s how that story goes. Morgenbesser is offered a choice between apple pie and blueberry pie, and he orders the apple. Shortly after, the waiter returns to say that cherry pie is also an option, to which Morgenbesser replies, ‘In that case, I’ll have the blueberry.’

That’s a strange pattern of preferences. The pattern is even stranger in our deontic case. Imagine instead that the waiter is offering Morgenbesser the options in Expanded Non-Identity.[11] Initially the choice is between (1) and (2), and Morgenbesser permissibly opts for (1). Then the waiter returns to say that (3) is also an option, to which Morgenbesser replies, ‘In that case, I’m morally required to switch to (2).’ The upshot is that the waiter can force Morgenbesser’s hand by adding options that are wrong to choose in the resulting option set. And turning the case around, the waiter could expand Morgenbesser’s menu of permissible options by taking wrong options off the table. That seems implausible.

Summarising the trilemma

Now the trilemma for narrow PAVs is complete and I can summarise. If these views say that (1) is permissible in Expanded Non-Identity, they imply that it’s Permissible to Choose Dominated Options. If they say that (3) is permissible, they imply that it’s Permissible to Prioritise Creating Mediocre Lives. And if they say that only (2) is permissible, they imply Losers Can Dislodge Winners. Each of these implications is seriously implausible.

5.2. A sequential choice problem for wide views

Now let’s consider wide views. Recall that these views say that we’re morally required to create the better-off person in cases like One-Shot Non-Identity:

One-Shot Non-Identity

(1) Amy 1

(2) Bobby 100

Wide views thus avoid the trilemma above. They can say that only (2) is permissible in Expanded Non-Identity without implying Losers Can Dislodge Winners. However, wide views have trouble with sequential choice. To see how, note the following. Because wide views are a class of deontic PAV, they imply that each option is permissible in the following two cases (where ‘—’ represents creating no one):

Just Amy

(1) Amy 1

(2) —

And:

Just Bobby

(1) Bobby 100

(2) —

Now suppose that we face these choices one after the other in a case that we can call:

Two-Shot Non-Identity

We make a choice in Just Amy, lock that choice in, and then move on to Just Bobby.

Suppose that we choose to create Amy in Just Amy and then later decline to create Bobby in Just Bobby. In that case, we’ve done something with effects on Amy and Bobby equivalent to the effects of choosing (1) in:

One-Shot Non-Identity

(1) Amy 1

(2) Bobby 100

In each case, we’ve created Amy at welfare level 1 and declined to create Bobby at welfare level 100. Wide views imply that choosing (1) in One-Shot Non-Identity is wrong. So what should wide views say about creating Amy and then later declining to create Bobby in Two-Shot Non-Identity?

Here are two things that wide views could say:

Permissive wide views

We’re always permitted to create the worse-off person and to later decline to create the better-off person in cases like Two-Shot Non-Identity.

Restrictive wide views

We’re never permitted to create the worse-off person and to later decline to create the better-off person in cases like Two-Shot Non-Identity.

I’ll take these two classes of view in turn. I’ll then consider views that chart a course between them.

5.2.1. Permissive wide views

Here’s a problem for permissive wide views: they make permissibility depend on factors that seem morally irrelevant. To see how, suppose that Amy’s and Bobby’s existence will be determined by the positions of two levers. By leaving the left lever up, we decline to create Amy. By pulling the left lever down, we create her at welfare level 1. By leaving the right lever up, we create Bobby at welfare level 100. By pulling the right lever down, we decline to create him. We first decide whether to create Amy, lock in that decision, and then decide whether to create Bobby.

Two-Shot Non-Identity with Levers

As it stands, the case is Two-Shot Non-Identity, and our permissive wide view implies that we are permitted to pull the left lever (thereby creating Amy) and then pull the right lever (thereby declining to create Bobby). But now suppose that someone lashes the two levers together so that our only options are pulling both levers or neither. Then our predicament is transformed into One-Shot Non-Identity and our permissive wide view implies that pulling both levers is wrong. That’s a strange combination of verdicts. Pulling both levers should either be permissible in both cases or wrong in both cases. It shouldn’t matter whether we can pull them one after the other.

5.2.2. Restrictive wide views

So consider instead restrictive wide views, according to which we’re never permitted to create the worse-off person and to then later decline to create the better-off person in cases like Two-Shot Non-Identity. Perhaps the latter choice is made wrong by the former, or perhaps each choice is permissible but the sequence is not.

These views also make permissibility depend on factors that seem morally irrelevant. This time the factor is what one chose in the (possibly distant) past. To see the problem, suppose that a friend is considering having a child and comes to you for moral advice. Per restrictive wide views, you not only need to ask your friend the usual questions about the child’s likely quality of life and how the child might affect existing people. You also need to ask your friend about their past procreative choices. If in the past your friend had a child with a worse life than this new child would have, your friend must have the new child to avoid wrongdoing. And now reversing the order of the cases: if in the past your friend declined to have a child with a better life than this new child would have, your friend must not have the new child. This latter implication seems to me especially counterintuitive. The new child’s life could be wonderful, but if your friend previously declined to have a child with an even better life, your friend is not permitted to create them. Restrictive wide views imply that there are cases in which we are not even permitted to create a person who would enjoy a wonderful life.

5.2.3. Intermediate wide views

Given the defects of permissive and restrictive views, we might seek an intermediate wide view: a wide view that is sometimes permissive and sometimes restrictive. Perhaps (for example) wide views should say that there’s something wrong with creating Amy and then later declining to create Bobby in Two-Shot Non-Identity if and only if you foresee at the time of creating Amy that you will later have the opportunity to create Bobby. Or perhaps our wide view should say that there’s something wrong with creating Amy and then later declining to create Bobby if and only if you intend at the time of creating Amy to later decline to create Bobby.

Views of this kind give more plausible verdicts in the previous cases – both the lever case and the enquiring friend case – but any exoneration is partial at best. The verdict in the friend case remains counterintuitive when we stipulate that your friend foresaw the choices that they would face. And although intentions are often relevant to questions of blameworthiness, I’m doubtful whether they are ever relevant to questions of permissibility. Certainly, it would be a surprising downside of wide views if they were committed to that controversial claim.

But in any case, there’s a more serious objection waiting for all forms of intermediate wide view: like permissive and restrictive views, they make permissibility depend on factors that seem morally irrelevant. We can prove this by contradiction. Assume for reductio (i) any kind of wide PAV, (ii) that permissibility doesn’t depend on lever-lashing, and (iii) that permissibility doesn’t depend on past choices. Consider again Two-Shot Non-Identity with Levers.

Two-Shot Non-Identity with Levers

When the levers are lashed together, the case is One-Shot Non-Identity and so wide PAVs imply that pulling both levers is wrong. If permissibility doesn’t depend on lever-lashing, then it’s also wrong to pull both levers when they aren’t lashed together. So we can infer: if in the past we’ve pulled the first lever, it’s wrong to pull the second lever. And if permissibility doesn’t depend on past choices, then it’s also wrong to pull the second lever in cases where we didn’t previously pull the first lever. So pulling the second lever is wrong simpliciter. But pulling the second lever is declining to create Bobby, and so we get the conclusion that we’re required to create Bobby, contrary to deontic PAVs. Since we began by assuming a wide PAV (one kind of deontic PAV), we’ve reached a contradiction and so we must reject at least one of our assumptions. Those who want to hold on to any kind of wide PAV must admit that permissibility depends on lever-lashing or on past choices. Those who want to avoid this dependence must reject every kind of wide PAV.

In sum, wide views sometimes remain undecided even when we know all the facts about who lives and how well. Their verdicts wait on the answers to questions that seem morally irrelevant: questions like ‘Did you miss the opportunity to have a happier child many years earlier?’ and ‘Will you carry out your choice by pulling two levers or one?’.

5.3. Summarising the case against deontic PAVs

My argument against deontic PAVs is a garden of forking paths. The first fork is One-Shot Non-Identity: narrow views are those deontic PAVs that permit us to create the worse-off person, and wide views are those deontic PAVs that require us to create the better-off person.

The fork for narrow views is a trilemma in Expanded Non-Identity. These views imply Permissible to Choose Dominated Options, or Permissible to Prioritise Creating Mediocre Lives, or Losers Can Dislodge Winners.

The fork for wide views is a sequential choice problem. Setting aside objections to specific instances of wide views, these views make moral permissibility depend on facts that simply don’t matter to anyone whose interests are at stake, like what you chose in the (perhaps distant) past and whether you make your choices by pulling two levers or one.

6. Conclusion

It’s important to figure out whether person-affecting views (PAVs) are true or false. If PAVs are true, we should be spending less on reducing x-risk. If PAVs are false, we (and the world at large) should be spending more on reducing x-risk, and we should be wary of the potential post-AGI failure-mode of creating way too few happy people.

I think that PAVs are false, but I also think that extant arguments against PAVs are weak. In this post, I’ve sketched out some arguments that I like better. I began with the simple argument and laid out problems for the classic PAV response. I then explained two arguments from Tomi Francis. These arguments imply that it’s good to create happy people, and better to create happier people. I then considered two kinds of deontic PAV – narrow views and wide views – and presented arguments against those. Narrow views face a trilemma in my Expanded Non-Identity case. Wide views run into trouble in my Two-Shot Non-Identity case.

  1. ^
  2. ^

    See Narveson (1967) for an early version of this response.

  3. ^

    Broome (1999, p.168) makes this argument. Greaves and Cusbert (2022) respond.

  4. ^

    The fact that the Person-Affecting Restriction and Existence Anticomparativism together imply (b) is known as the ‘non-identity problem’.

  5. ^

    Nebel (2019) offers one explanation.

  6. ^

    See his paper for more detail.

  7. ^

    See (for example), Roberts (2011), Meacham (2012), and Frick (2022).

  8. ^
  9. ^
  10. ^

    This condition is the negation of Podgorski’s (2021, 362) Losers Can’t Dislodge Winners.

  11. ^

    It’s a very unusual restaurant.