As a first step of the argument, observe that (most) experientialist theories cohere perfectly with welfare sentientism. First, note that no experientialist theory can be overextensive: by definition, experientialism implies that only what can be experienced may contribute to wellbeing, and as non-sentient beings cannot experience, no non-sentient being can have an experientialist welfare good. An experientialist theory may be incomplete. For example, a theory that maintains that only the experience of viewing Rembrandt’s The Night Watch is good is strictly speaking experientialist, but is clearly incomplete. Many have led good lives, had positive levels of welfare, suffered or have been harmed without ever having seen The Night Watch. However, most plausible experiential welfare goods are not particular experiences, but determinable properties that apply to all experiences. Most notably, any experience can be evaluated (though perhaps not fully evaluated) on a hedonic scale. This is not to say that all experiences are either pleasurable (enjoyable) or painful (contain suffering). Some experiences may be hedonically neutral, or anhedonic. But an anhedonic experience is a rather neutral good. So, a hedonist would, not implausibly, describe an entity that has such experiences as a welfare subject with neutral welfare. An experientialist who believes other features of experiences also contribute to wellbeing would have tools available to ascribe non-neutral welfare values even to such anhedonic experiences. Most importantly, however, since any experience can at least be evaluated in hedonic terms, any experientialist theory that includes hedonic levels as a welfare good will also not be incomplete. So, any experientialist theory that includes general determinable properties like hedonic properties as one welfare good, will cohere perfectly with welfare sentientism.Footnote 8

As discussed in Sect. 2, extra-experientialist theories of wellbeing can take a number of shapes. In order to see to what extent extra-experientialism is compatible with welfare sentientism, I review desire-satisfactionism, perfectionist theories, brute list theories, and a number of goods that typically make it on (extra-experientialist) brute lists: friendship, knowledge, and achievement, and finally I discuss hybrid theories that give experiential goods a central role.

Desire-satisfaction is incomplete

The nature of desire is a controversial subject, but at least on some plausible conceptions of desire, desires necessarily involve a certain phenomenology (see Schroeder 2006 for an overview). If that is true, in order to have desires, one needs to be sentient. However, a first problem for the compatibility of welfare sentientism and desire-satisfactionism is that while all desirers may be sentient, not all sentient beings are necessarily desirers. Any particular suggestion can be controversial, but it seems plausible that late-stage fetuses are sentient but lack desires, and that earthworms and simple fish may be sentient but lack desires (see, for example, Dorsey 2017, 692, ft. 10 for a similar claim). About this category of beings, desire-satisfactionism simply does not have anything to say. Consequently, desire-satisfactionism is incomplete: if welfare sentientism and desire-satisfactionism are both true, it would be puzzling why desire-satisfactionism only applies to a subset of welfare individuals.

As discussed above, there may be two solutions to incompleteness. First, we may simply conclude that for all beings that are not desirers, but are sentient, welfare levels are zero. This, however, would be deeply implausible. If a sentient fetus is physically hurt and feels pain, this is not good for her, and the same goes for any other non-desiring sentient being.

Alternatively, we may simply posit that a different theory, perhaps a hedonistic theory, applies to these creatures, while desire-satisfactionism applies to desirers. This would violate welfare invariabilism, and create a significant burden of explanation on the part of the desire-satisfactionist. But, what’s more, for creatures like sentient fetuses—creatures that do not have desires yet, but will get desires in the near futures—this implies an odd welfare dynamic (Lin 2017): if welfare hedonism is true of fetuses, but as soon as fetuses or babies start having desires desire-satisfactionism becomes true, wellbeing may start making odd leaps. For instance, if our first desires are not satisfied, a baby’s wellbeing level may drop from a sufficient level to a very low level by gaining the ability to desire. As Lin argues, this is odd, and difficult to rationalize.

Desire-satisfactionism is overextensive

There is a further problem for desire-satisfactionist accounts. While desires may necessarily be formed by sentient beings, the same does not hold for the satisfaction of desires. In fact, we may hold numerous desires for things that will, or can, only be satisfied after we die: the success of the lives of our children, how our will is executed, or recognition for our life’s work. When we hold a desire for our will to be executed in the way we intended, and this actually occurs, a desire is satisfied.

We may say that executing a friend’s will successfully will benefit the friend posthumously. This would appear to violate welfare sentientism—as the dead are no longer sentient. So, while the first problem poses an incompleteness problem for desire-satisfactionism and welfare sentientism, this problem shows that desire-satisfactionism may also be overextensive. In response, the desire-satisfactionist could exclude the satisfaction of desires that are satisfied posthumously. This would eliminate the overextensiveness problem, but would be ad hoc (see Parfit 1984, 495, for a similar argument). Recall that desire-satisfationism typically makes space for extra-experiential benefits—what Dorsey has called the “distance allowance”. If desire-satisfaction allows for disbenefit through frustrated desires that never enter one’s experience in general, it is difficult to see what is so special about death such that desires about posthumous events cannot affect a person’s wellbeing.Footnote 9

In response, a desire-satisfactionist can point out that we have assumed that when a desire is satisfied posthumously, the benefit must also take place posthumously. As plausible as this may seem, recently Dorsey (2013) and Bruckner (2013) have defended the view that the benefit of posthumous satisfaction of desires occurs during a person’s lifetime (see also Pitcher 1984; Luper 2004).Footnote 10 On this view, posthumous desire-satisfaction benefits a person at the time an event that occurs posthumously is desired by the living desirer. This would mean that posthumous acknowledgment of a person’s work is good for that person when that person is desiring that they will be acknowledged for their work. This would help make desire-satisfaction compatible with welfare sentientism. After all, it would not imply that welfare goods are held by non-sentient (dead) individuals. While this solution seems highly counter-intuitive to me, I grant that foot-stompingly denying its plausibility is not a fruitful way to tackle this position (though cf. Portmore 2007).Footnote 11 Rather, I point out two implications of this view that strongly speak against it.

A frequently raised objection against this view is that it implies backward causation—events in the future cause wellbeing states now—and consequently, is deeply implausible as a general feature of value. However, as Donald Bruckner (2013) has argued, this need not be the case. The events at time t 1 are not affected by t 2 , only their value for the person having the desire is: “This is not backward causation, but merely waiting to see how things turn out” (26). However, granting that this solution does not involve physical backward causation, it does imply a backward determination of wellbeing value (Scarre 2012 suggests “backward significance”): how good a particular moment is now, may be determined by future events. This has two problematic implications in the context of posthumous harm and benefit.

First, it seems plausible to think that all value can, in principle, be appreciated, that is, recognized, experienced, or perceived as good. However, if Bruckner and Dorsey’s suggestion is correct, there are substantial categories of wellbeing value that cannot possibly be appreciated in this way. If I have a desire that gets satisfied posthumously, and I have not told anyone about this desire, this creates a value for me that neither I, nor anyone else, could possibly recognize as such. For example, I may wish that my funeral is well-attended, but that uncle Derek does not come, because I secretly hold a grudge against uncle Derek. If uncle Derek indeed does not come, who could appreciate the value that this has created for me? The problem here is not so much that the value is not appreciated, because, in part, this may be what is at stake in the debate between experientialism and extra-experientialism. However, the problem is that it could not possibly be appreciated: the welfare subject is dead, and no one else knows of the existence of the desire that is satisfied. This gives the value a metaphysically mysterious character: if the purported value of a good cannot possibly be appreciated by anyone, why would we think it has value?

Second, the solution proves too much. As long as someone has future-directed desires, then their wellbeing is undetermined until the future has determined these desires satisfied or frustrated, or the success achieved or not. This may seem plausible for things that occur at our funerals, but if we accept that our desire-satisfaction about our funeral may make a difference to us during our lifetime, then we must also think that any desire that is satisfied (or frustrated) posthumously still plays a role in determining our lifetime wellbeing. For example, if Julius Caesar held a desire for posthumous recognition, then what is being said about Caesar during history classes (and whether he is discussed at all) still affects Caesar’s wellbeing. His wellbeing during his life thus still fluctuates based on the memory, recognition and appreciation of him by people today. This becomes particularly mind-boggling when people hold desires for the continued existence of the human race: if people hold these desires, a person’s wellbeing only becomes determined by the death of the last human. After all, the satisfaction of this desire only becomes determined once it is frustrated, and humans no longer exist. This means that ultimately, a person’s wellbeing is practically never determined. The question What is the degree of Nathan’s wellbeing? is not answerable, at least as long as Nathan has desires that still extend into the future. There is a well-known ancient Greek saying: “call no man happy, until he is dead”.Footnote 12 This may have some plausibility. However, the view that the satisfaction of desires contributes to wellbeing at the time the desire is held would imply that no person’s life can be called good until their last desire has been satisfied or frustrated. That seems to be an absurd stretch.

If these considerations are convincing, then posthumous desire-satisfaction cannot affect wellbeing during a person’s lifetime, and if it does, it must do so after someone dies, at which time, a person is no longer sentient. Consequently, posthumous desire satisfaction creates an overextensiveness problem for desire-satisfactionism.

Flourishing accounts

According to perfectionist, or flourishing, accounts of wellbeing, wellbeing consists in a number of irreducible goods that are connected in that they all contribute to the exercise of a person’s natural capacities, or the fulfilment of her nature. The problem for perfectionist accounts is that they are overextensive. There are some entities that have natures that can be fulfilled without having sentience. Most plausibly, most plants are like this: a plant can function in accordance with its nature, even though plants are probably not sentient.Footnote 13 If welfare sentientism is correct, the explanandum for flourishing accounts is the fact that there are many more entities that can flourish than there are entities that are sentient. Why, if flourishing is what ultimately matters to wellbeing, would it only matter to sentient beings? Plants, even if they are non-sentient, can flourish.

This question has received some attention in the related discussion about moral status. Nussbaum (2009), for example, discusses a version of this challenge in the context of moral consideration, in which she seems to doubt the sentience of mosquitoes:

It seems minimally bad to kill a mosquito, because it appears that a mosquito does not feel pain. It is easy for Singer [as a utilitarian] to explain this conclusion; it is more difficult for the capabilities theorist to do so, since the good resides in opportunities for flourishing, not in sentience alone (2009, 361).

Nussbaum agrees with the intuitive appeal of the utilitarian demarcation. Nevertheless, she believes that sentience is not a necessary condition, but rather one among a number of sufficient conditions for moral consideration. Nussbaum’s claim concerns a different target—the moral status of beings, rather than their wellbeing. Nevertheless, it illustrates the tension between the significance we attach to sentience and flourishing accounts of wellbeing.

If flourishing constitutes wellbeing, and welfare sentientism is correct, flourishing accounts need to explain why the flourishing of non-sentient entities does not constitute wellbeing for them, even though it does constitute wellbeing for sentient beings. Within the flourishing axiology, such a constraint does not appear to have any rationale. Above, I have suggested that the only solution to overextensiveness is to adopt an ad hoc restriction on whom the theory applies to—namely, flourishing only matters for sentient beings. This is unsatisfactory though. How can limiting wellbeing to sentient beings be compatible with an account of flourishing in which experience does not play any role? Perfectionist accounts seem to have no resources available to satisfactory answer this question.

Brute list theories

Brute list theories are theories of wellbeing that are pluralistic, but, different from desire-satisfaction and perfectionist accounts, not unified by a general principle. Their pluralist axiology allows experiential goods to be listed. Consequently, it is not the case that experience plays no role in their axiology. Any brute list that contains an experiential good (such as pleasure) as one item on the list is able to explain why all sentient beings are welfare subjects, as all are capable of having good or bad experiences. Any such list thus avoids the incompleteness concern. However, brute list theories would face similar problems as flourishing accounts of wellbeing if they contain items that apply to non-sentient beings. Whether they do depends on the list. We can look at a number of the most promising and common candidates: knowledge, achievement, and friendship.

A first problem for the coherence between welfare sentientism and these goods is that it is unclear whether sentience itself is required to obtain them. Consider Chalmers’s (1996) philosophical zombie. The philosophical zombie is able to do most of the same things that others can: for example, they can go to university, drive cars, and be in romantic relationships. However, they lack phenomenal experience. They are, in other words, not sentient. However, if Chalmer is right, it is unclear that his zombie cannot have knowledge—after all, the zombie is able to finish his university exams)—; achieve certain things—for all we know, Einstein may have been a zombie; or maintain friendshipsFootnote 14—his friends, after all, would not realize he is a zombie. If that is true, the coherence problem for brute list theories is clear: non-sentient entities hold welfare goods.

However, there is a further problem, which is similar in shape to the problem that faced desire-satisfactionism. In order to see this, we need to look at the different goods in turn.

First, consider friendship. Even if sentience is necessary for the formation of friendships, it is not obvious that the same applies to the holding of friendships. In particular, consider the question whether friendships survive death. There are different possible answers. A first is to suggest that it does. This seems intuitive, as we generally say that a funeral is visited by the friends of the deceased, not by their former friends. However, if so, it is clear that friendship is a good that presents an overextensiveness problem: if we keep our friends after death, the deceased have a welfare good. So, it will have to be explained why the deceased have no welfare, even though they do have a welfare good.

A second answer is to deny that friendships survive death, even though friendship is an extra-experiential good. This also seems to be a reasonable suggestion. This would solve the tension between the good of friendship and welfare sentientism: no dead, and thus non-sentient, beings would have friends. However, this solution gives too much significance to death in friendship, especially if we can think of the good of friendship as extra-experiential. Given that we usually think we can benefit from friendship even when we are apart from our friends and cannot experience one another’s companionship, it is not clear why death (another way of being apart) would end friendships. To see this, consider an example: a friend, Elizabeth, talks badly about another friend, Emma. As some extra-experientialists may believe, this by itself may harm Emma. Imagine that this happens at 12:41 on a Thursday afternoon. Now, as it turns out, Emma dies at 12:39. If that is true, on this view, Elizabeth’s gossip did not disbenefit the second friend after all, as it occurred after Emma’s death. But this seems odd. The harming of the friendship seems very similar in case the second friend would die at 12:45, 12:55, or 21:00, and it seems difficult to see why it would harm someone in these cases, but not in case a person dies at 12:39.

Another suggestion is to claim that friendship only benefits us when we experience the companionship of friendship, or think about our friends in some positive way. This would explain why only sentient beings can benefit from friendship, but this would turn friendship into an experiential good. So, if we want to see friendship as valuable in an extra-experientialist way, we would have to be committed to the view that friendships may benefit or disbenefit us after we die, and consequently, be overextentive with respect to welfare sentientism.

Now, consider achievements. As Gwen Bradford suggests “achievements are characterized by a process–product structure: all achievements have a process, which culminates in a product” (Bradford 2013, 205).Footnote 15 On her view, achievements are more valuable when they are more difficult, or have a more valuable product, which can be further explained by the human capacity to exercise her will.Footnote 16 While the exercise of effort and will (to overcome difficulty) may be possible only for sentient beings, the product of achievement may be achieved long after the individuals who have exercised their efforts have died (and stopped being sentient). If the product of an achievement contributes to its value, the achievement of this product must contribute to a person’s wellbeing long after they have died.

Consider, for example, the time and effort invested by a diplomat, who aims to achieve global cooperation on a significant goal—such as the reduction of pollution. She successfully brings together a number of international congresses, but none are successful. She dies, and, inspired by a letter she wrote on her deathbed, the international community comes together and signs the agreement the diplomat has always dreamed of. This achievement is obtained posthumously, so it certainly seems the achievement is achieved by someone who is no longer sentient.

Again, defenders of the wellbeing value of achievements have two moves available. First, they may claim that achievements only contribute to a person’s wellbeing if that person is alive to see the product. This would keep the compatibility of welfare sentientism with this value. However, it would be difficult to see what the rationale for this move would be without reducing the value of achievement to the value of the experience of achievement, in other words, reducing achievement to an experiential value.

Second, they may claim that posthumous achievement contributes to a person’s wellbeing, while that person is alive. This parallels the move of the desire-satisfaction theorist who claims that posthumous satisfied desires contribute to a person’s wellbeing at the moment she is desiring them. The problems it faces are therefore also the same: it entails that our wellbeing may be undetermined for very long stretches of time after we die (if ever), and it may imply principally unappreciatable value if people pursue private projects that no one knows about, but that nevertheless are achieved posthumously.

Finally, knowledge. Knowledge is extra-experiential because while beliefs are (plausibly) mental states, knowledge consists of a relation between this mental state and the world. Given a certain belief content (that X), the difference between knowledge (true belief that X) and false belief need not register in our experience in any way. For example, we may believe that our teenage child is quietly reading in their room, while they in fact have sneaked out to go to a friend’s party. Such situations may also occur about future-oriented beliefs. For example, I may believe that my children will have a bright future. When I pass away, and this belief is then determined to have been true, we end up with a similar problem as with friendship, achievement, and desire-satisfaction: either I hold the good of knowledge at the moment it is determined to be true, but this would imply I have a welfare good when I am no longer sentient; or we can maintain that it benefitted me while I was still alive, leading to similar problems as before: a person with future oriented beliefs will have an undetermined level of wellbeing for long after they die, and if these beliefs are held privately, they are principally unappreciatable.

Alternatives and hybrids

So far, I have argued that desire-satisfactionism faces a problem of incompleteness. And, all extra-experiential welfare goods that we have discussed face a common problem: overextensiveness. This latter problem can be generalized as follows:

(1) On extra-experientialist accounts of wellbeing, welfare goods may affect our welfare without entering into our experience (2) For an extra-experientialist theory that contains such a good, X, these theories either allow that X can be had by non-sentient beings or that X can be had by sentient beings after death (when sentience is gone). (3) In order to be coherent with welfare sentientism, theories that are overextensive must either adopt an ad hoc constraint, or require backward determination. (4) Neither of these moves is a satisfactory response to the dilemma.

So far, I have focused on extra-experientialist goods that are commonly included in philosophical theories of welfare. To what extent is this argument generalizable to all welfare goods? There is no guarantee that this argument will apply to all extra-experientialist goods, however, it is difficult to think of extra-experientialist goods to which it does not apply.

As a final example, I discuss how this argument even applies to experientialist-extra-experientialist hybrids that maintain that good experiences, such as enjoyment, are necessary for wellbeing, but take the value of this enjoyment to rely on (possible) relational factors. A prominent example is (Sumner 1996, ch.6) authentic happiness account of wellbeing according to which wellbeing is identical to life-satisfaction (or, happiness) except if the life-satisfaction is unauthentic, that is, when it is based on standards that are not autonomously formed, or based on false information that, if it were to come out, would affect a person’s evaluation of her life given a person’s own set of priorities. This view is extra-experiential. To use Sumner’s own example, a businessman may be happy because he has a happy marriage and successful business, not knowing that his wife is having an affair behind his back, and his business partner will betray him. According to Sumner, these latter facts make him worse off, even though he does not experience them. At the same time, though, Sumner’s view has a natural connection with sentience, and appears to fit well with welfare sentientism. In fact, it may even explain the necessity of sentience for being a welfare subject.Footnote 17

However, again, the same argumentative pattern applies: our degree of authentic happiness may change posthumously. While we are alive, we may be happy in light of expectations we have about the future, such as my children having a bright future in front of them after I die. Our happiness about this may turn out to be inauthentic (the future of our children is not bright after all).Footnote 18 This again, implies that a significant part of my wellbeing would be determined after my death, creating the possibility of principally unappreciable welfare value. For example, I may take satisfaction in the posthumous appreciation of my colleagues, that only becomes authentic when it actually occurs posthumously. If this is problematic in the case of desire-satisfactionism, then it would also be problematic for theories that suggest that the wellbeing value of happiness depends on relational properties that may be determined after we die.Footnote 19

Taking stock

We can now fully articulate the sentience argument for experientialism. A first central premise of the argument is that all and only sentient beings are welfare subjects. A second is that there should be a certain coherence between the question “Who is a welfare subject?” and “What constitutes wellbeing?”. In principle we should expect a theory that maintains that wellbeing consists in X to also maintain that all beings that have good X are welfare subjects. And if that theory states that wellbeing only consist in X, the welfare of all welfare subjects is described by X. In case of experientialist theories, this coherence holds perfectly if welfare sentientism is true. For other theories, this is not clear. First, theories that do not contain experiential goods—such as desire-satisfactionism, are incomplete. They can only describe the welfare of a subset of all welfare subjects. Second, extra-experiential theories are typically over-extensive. While these theories may be coherent with welfare sentientism, in order to be coherent, they either need to exclude certain entities that hold wellbeing goods in an ad hoc fashion, or they need to postulate a very particular way in which external circumstances affect our wellbeing, namely, that future circumstances affect our wellbeing today. The first is unattractive for obvious reasons, while the latter is unattractive because it has implausible implications. This is, to be sure, not a knock-down argument against these theories. However, it should count in favor of experientialist theories that they are able to answer the two central questions—“Who is a welfare subject?” and “What constitutes wellbeing?”—in a simple and unifying way, without having to make such unattractive postulations.