Irreplaceability and the Desire-Account of Love

Lovers do not relate to their beloveds as seats of valuable qualities that would be replaceable for anyone with relevantly similar or more valuable qualities. Instead, lovers take their beloveds to be irreplaceable. This has been noted frequently in the current debate on love and different theories of love have offered different explanations for the phenomenon. In this paper, I develop a more complex picture of what is involved in lovers taking their beloveds to be irreplaceable. I argue that in order to account for the beloved’s irreplaceability, a theory of love must meet two conditions: it must explain the subjective aspect as well as the moral aspect of the beloved’s irreplaceability. I show that current theories of love fail to meet these conditions, either one or both of them, and I offer an alternative account that does - an account according to which love is understood as a special kind of desire for the beloved as a person. The aim of this paper is twofold: first, to give a more nuanced picture of the beloved’s irreplaceability, acknowledging in particular that there is a moral aspect to the phenomenon that has not been attended to thus far; second, to introduce and motivate a new desire-based account of love.


Introduction
Lovers do not relate to their beloveds as seats of valuable qualities that would be replaceable for anyone with relevantly similar or more valuable qualities. Instead, lovers take their beloveds to be irreplaceable. This has been noted frequently in the current debate on love and different theories of love have offered different explanations for the phenomenon. 1 In this paper, I develop a more complex picture of what is involved in lovers taking their beloveds to be irreplaceable. I argue that in order to account for the beloved's irreplaceability, a theory of love must meet two conditions: it must explain the 'subjective aspect' as well as the 'moral aspect' of the beloved's irreplaceability. I show that current theories of love fail to meet these conditions, either one or both of them, and I offer an alternative account that does -an account according to which love is understood as a desire for the beloved as a person, which I spell out as a desire for 'deep conversation' with the beloved. The aim of this paper is twofold: first, to give a more nuanced picture of the beloved's irreplaceability, acknowledging in particular that there is a moral aspect to the phenomenon that has not been attended to thus far; second, to introduce and motivate support for this desire-based account of love.
In the first section, I outline what it means for a lover to relate to their beloved as irreplaceable and in what sense this is also a moral relation. In the second section, I discuss three currently prominent ways of explaining the beloved's irreplaceability and argue that they fall short. In the last section, I sketch a desire-account of love that fits the criteria and that I take to be attractive even independently of the irreplaceability challenge.

The Subjective and the Moral Aspect of Irreplaceability
Imagine a small child, Ada. Ada's parents are offered a deal to replace Ada for another child, Eva. Replacing Ada for Eva would mean that instead of Ada, the parents would now share their lives with Eva. Ada and Eva are very similar: in fact Eva has all the qualities Ada's parents value and care for in Ada. But Eva also has some desirable qualities that Ada lacks and will not acquire any time soon -among other things, Eva is a better sleeper. Further, her parents are assured that Ada would not be harmed in the replacement process: she would be welcomed by a new family where she could flourish, and in any case, she is too young to realise what is going on.
Despite this assurance, it seems that if Ada's parents were willing to accept the deal and replace Ada for Eva as a result of comparing their respective qualities in this way, we would doubt that they loved Ada. The intuition here seems to be that if they loved Ada, they would want to continue sharing their lives with Ada independently of how Ada's qualities compare to Eva's (which is not to say that they would not want Ada to have some of Eva's qualities). 2 And so they would not accept the deal, at least not because of the above kinds of comparative value judgments. 3 Another way of expressing the thought would be to say that loving parents care for their children as particulars rather than (merely) as in principle replaceable instantiations of some type of value. And this is not just a feature of parental love but seems to be true of the other forms of interpersonal love, too: romantic lovers, close friends, siblings who love each other and so on, all seem to relate to their beloveds as irreplaceable in some, further specifiable sense.
2 It is compatible with not wanting to replace Ada for Eva that the parents would want Ada to have some of Eva's valuable qualities that Ada currently lacks. The intuition is not that lovers would never want their beloveds to gain some new qualities, but only that lovers would not consider their beloveds replaceable for other persons on the basis of comparative value judgments. 3 Perhaps there could be other reasons they would adopt Eva and give Ada to a different family: perhaps they believe that Ada would flourish more in a different family, and so they might decide to part with Ada even if it would break their heart. I am not claiming that loving parents would never decide to part with their child. This also explains why, when lovers are grieving over the death of their beloved, they cannot just get 'another one' in the way one can get another copy of a book if the first one gets lost. Receiving another copy of a book we lost often amounts to a full compensation, where 'compensation' is understood as a kind of cancellation of the loss, so that we are as well off as before the loss in all relevant respects. Consequently, after having been fully compensated, we usually stop feeling aggrieved about the loss, and (unless we are told further specifics of the case) we also ought to stop feeling aggrieved, rationally speaking. Sometimes, only partial compensation is possible: perhaps the lost copy had some notes scribbled on the margins that we would have liked to keep, and so while receiving a new copy cancels out some of the loss, it does not cancel out all of it. In that case, our feelings about the loss often would and rationally should react in proportion to the compensation.
In the case of grieving lovers, however, neither full nor partial compensation seems to be possible. The reason is not just that it tends to be difficult for lovers to find another person who shares all of their beloved's relevant qualities. To return to Ada and Eva: if Ada's parents had adopted Eva after Ada's death, this could not cancel out their loss of Ada in the way a new copy of a book can (sometimes) cancel out the loss of the first. For we would neither expect Ada's parents to stop grieving over Ada upon Eva's arrival, nor would we think of them as irrational if they did not stop grieving. Eva could not even count as a partial compensation for Ada, for we would neither expect nor rationally require the parents' grief to respond in proportion to the extent Eva 'covers' Ada's properties. In fact, we would be bewildered if it did.
This is not to say that adopting and coming to love Eva could not help the parents in dealing with their loss. In general, saying that lovers could not get compensated for losing their beloved does not mean that they would never fall in love again, and if they did, the joy associated with that might eventually make it easier to live with their loss. But learning to live with a loss is not the same as having been compensated for it in the above sense.
It often takes lovers some time before they are able to even conceive of loving again after losing a beloved. But we can also imagine that an acutely grieving lover wants to fall in love again, hoping that this will help with the pain, as just outlined. For that purpose, it would not matter whether the new beloved is qualitatively similar to the lost one or not. It is also possible to imagine a grieving lover who specifically desires to meet a qualitative replica of their lost beloved, however, and this is not necessarily incompatible with the nocompensation-claim either. One explanation might be that the lover hopes to be deceived into believing that the replica is in fact their beloved. In that case, the grief would indeed disappear -though not because the replica is a compensation for the lost beloved, but because the lover (deludedly) takes the replica to be the beloved. In a state of desperation, one might well prefer to be deceived than to continue bearing the truth. Another possibility is that, while fantasising about this scenario, the lover does not realise that 'receiving' a replica will not compensate them for their loss. Love is not necessarily always a fully self-aware state, and just as we can be unaware of being in love with someone, so we can be unaware of what our love involves (at least for some time). Now, relating to a person as irreplaceable is not necessarily unique to the attitude of love. It also does not fully explain a lover's grief. People who do not love Ada in the same way her parents do might still agree that there is no compensation for losing Ada, and not just for the parents, i.e. the lovers, but in some sense for themselves and 'the world at large' either. At least, this is how we often think about another person's death: independently of our specific relations to them, we think that when a person dies, something of value has been lost to the world that not even a qualitative replica of them could replace. But while non-lovers can see and also be affected by this irreplaceable loss, they won't generally grieve over someone else's death in the way a lover does. The impossibility of compensation, of replacing the value that is lost, does not injure them in the way it injures the lover.
It seems, then, that we take there to be such a thing as objective irreplaceability: the kind of irreplaceability persons have qua persons, for instance. 4 But the irreplaceability a beloved person has for a lover goes beyond that. The beloved is irreplaceable for the lover in the sense that the lover will be personally injured by their loss -they won't know how exactly to go on living afterwards, and they will say things such as 'for nothing now can ever come to any good'. 5 I call this the 'subjective aspect' of the beloved's irreplaceability for the lover, because it seems to (also) depend on the lover and the attitude they have towards the beloved qua lover, and not (just) on the objective nature of the beloved. Another way of putting it is that the beloved is irreplaceable for the lover in a sense in which they are not irreplaceable for non-lovers.
Taking their beloveds to be irreplaceable is also morally significant for lovers, however. Take Ada and Eva again: as before, Ada's parents are offered a deal to replace Ada for Eva and they are assured that Ada will not suffer any harm from the replacement. The parents love Ada, and as lovers in their right minds, they would refuse the deal, as we have said. But if there was a situation in which they were not in their right minds and they accepted the deal -in a moment of severe confusion, say, or emotional numbness where they are unsure or not aware of their own love 6 -they would not only be extremely dismayed as soon as Ada was gone and they came to their sense (given that they do love Ada). They would also feel guilty about having accepted the deal.
Since we have stipulated that Ada's parents are assured that there would not be any harmful consequences, their guilt could not be about harming Ada. 7 We could even compare the following two scenarios: in the first, Ada's parents decide to part with Ada because they believe Ada would be better off in a different family. They might be heartbroken about parting with Ada, but -assuming they genuinely believe this is overall better for her -they would not necessarily feel guilty about parting with her. In the second, Ada's parents accept the replacement deal on the basis of comparative value judgments about Ada and Eva in a moment of confusion, but afterwards they learn that Ada is not only not harmed but better off at the new family. Here, unlike in the first scenario, if they love Ada, it is plausible that they would still feel guilty -and since the only difference is that they momentarily related to Ada as replaceable, their guilt must be directed specifically at this.
One might wonder whether 'guilt' is really the correct term for the feeling in question. Perhaps the parents feel bad in a normative sense simply because they did not live up to their love in this situation. In accepting the deal, they did not behave in a way an ideal lover would, and lovers often want and expect themselves to be ideal lovers. This sense of failure or disappointment with themselves may well be there, too, but it is not the whole story. For the feeling I have in mind is directed at the child in particular: when coming to their senses after accepting the deal, the parents feel as if they had somehow wronged Ada by momentarily relating to her as replaceable. Apart from other emotions such as disappointment and heartbreak, they also experience this sort of moral dismay, and 'guilt' does seem to be the right term for this. This is what I call the 'moral aspect' of the beloved's irreplaceability: the fact that lovers also believe that relating to their beloved as replaceable would be some form of wronging them and that they therefore ought not to relate to them as replaceable. At least not insofar as they relate to them as lovers. If their beloved happens to also be their doctor or their lawyer, they may be replaceable for the lover in that function.
Note that again, in certain contexts, this might also be true for non-lovers. The objective irreplaceability a lot of us take persons to have qua persons is also morally significant for us, independently of how we are related to a particular person. For example, when a person dies, not only do many of us believe that something of value has been lost that not even a qualitative replica could replace, but we are morally disturbed if someone sincerely suggests otherwise. There seems to be something morally wrong about relating to another person as entirely replaceable (in thought and in action). At least in contexts in which the value someone has as a person is at stake, and not their value as a doctor, lawyer, or some such, many of us believe that we ought not to consider and / or treat them as (entirely) replaceable. However, whereas this is not part of the attitude of non-lovers per se, believing that one ought not to relate to one's beloved as replaceable in a moral sense of 'ought' is part of the attitude of love. (I come back to this contrast.) A theory of love that wants to explain the beloved's irreplaceability -i.e. that wants to make rational sense of why and in what way lovers relate to their beloveds as irreplaceableshould be able to explain both the subjective as well as the moral aspect of the phenomenon. In the following, I refer to these as conditions one and two, respectively. And in the course of discussing three prominent accounts of love and irreplaceability in the next section, I will further refine the picture we have thus far.

Three Accounts and Where They Fall Short
Before I start, it is helpful to briefly note what love cannot be if we take the phenomenon of the beloved's irreplaceability seriously: love cannot be an attitude that is fully explained and justified by value judgments about the beloved's beauty, wit, or other such valuable qualities. For if to love another person means no more than judging them to be beautiful or funny, say, and desiring and caring for them as a result, then why shouldn't lovers be willing, in principle, to replace their beloveds for persons with relevantly similar or better qualities, and desire and care for them instead? In fact, according to the quality theory, it seems that lovers should be thus willing, in both an expectant and a rational sense of 'should'. But (analogously to the compensation-scenario above) we neither expect lovers to be willing to replace their beloveds, nor judge them to be irrational if they are not. In fact, as we saw in the previous section, we expect lovers not to be thus willing and if they are, we either doubt that they are actual lovers or we doubt whether they are in their right minds. The quality theory not only contradicts but implies the polar opposite of what we have said so far. So we should rule it out. 8 One response might be to distinguish between deontic and non-deontic reasons in this context. 9 Deontic reasons for some attitude x both justify and rationally require x, whereas non-deontic reasons for x only justify but do not rationally require x. If the beloved's valuable qualities only provide the lover with non-deontic reasons for love, they justify the lover's love without rendering the absence of love irrational. So if, in a relevantly similar situation, the lover did not respond with love, the lover would not thereby be irrational. This way, we can explain why we should not be surprised and why it would not be irrational, if lovers refuse to replace their beloveds on the basis of comparative value judgments (despite their love being based on and justified by value judgments that are in principle open to comparison).
The distinction between deontic and non-deontic reasons does not solve the irreplaceability problem for the quality theory, however. On this picture, while there would not be anything wrong with a lover refusing to replace their beloved in the above fashion, there would also not be anything wrong with a lover who did not refuse. Both options are equally rational and compatible with love here. But the second option is not in fact compatible with love, so the irreplaceability problem remains. The three accounts of love I discuss in the following are alternatives to the quality theory that try to address this problem.

Volitional accounts
I turn to volitional accounts first, according to which love does not imply any value judgments but is a purely volitional phenomenon. Harry Frankfurt (2004Frankfurt ( , 2006 offers the most developed of these accounts, so I focus on his. But my main point applies to volitional theories in general. 10 According to Frankfurt, love is unconditional care for the beloved, and value judgments about the beloved are neither necessary nor sufficient for this kind of care. Love has causes, but no reasons, in the sense that from the lover's point of view, there does not have to be anything about the beloved that speaks in favour of and justifies her love. Instead of having reasons, love generates practical reasons, insofar as it determines the lover's final ends: to care for something unconditionally means to value its continued existence and wellbeing as a final end, rather than instrumentally or, more generally, non-finally (where 'valuing some- 8 Delaney's (1996) distinction between the grounds and the object of love is sometimes cited as a possible response on behalf of the quality theory. However, even if we agree that the beloved's qualities are only the grounds in the sense of the reasons for love, whereas the object of love is the beloved themselves, the problem still arises: the qualities of the beloved would have to make the attitude of love intelligible on this picture, i.e. they would have to explain and justify it; and if taking the beloved to be irreplaceable is a part of love, they would also have to explain and justify this aspect of love. But the objection is precisely that pointing to the qualities alone cannot explain this aspect of the attitude of love. See Clausen (2019: 350) for a similar objection. 9 See Jollimore (2017:Sect. 2) for discussion in the context of love. See Little (2013) for a general defence of the distinction. 10 For recent defences of volitional accounts, see e.g. Jacobson (2016) and Han (2021). See also Smuts (2014) for further discussion of 'reasons-' and 'no-reasons-accounts' of love.
thing' just means being disposed to act on its behalf or to promote it in certain ways, rather than judging it to be valuable in some respect). 11 This also provides an explanation for the beloved's irreplaceability. For whatever we value as a final end is irreplaceable to us -in fact, this is partly what it means to be a final end. Consider non-final ends first. Among the non-final ends are means to other ends, and something we value as a mere means is valuable to us only insofar as it produces the end. 12 It does not matter to us as the particular thing it is. The same is true of other non-final ends: we do not value them as the particular things they are, but only relative to other ends. Hence, it makes sense for us to be willing to replace them for anything that stands in the same relation to these other ends (for example something that produces them just as or more effectively). But something we value as a final end, we do value as the particular thing it is and not just as a placeholder for something else. And this entails that we take it to be irreplaceable: nothing but this particular thing will do for us. So Frankfurt's account meets condition one: it can explain the subjective aspect of the beloved's irreplaceability. 13 However, it does not have the resources to explain the moral aspect of the phenomenon -it does not meet condition two. Think about the parents in the above scenario again who, in a moment of confusion, agree to replace their child even though they love their child. According to Frankfurt's account, by accepting the replacement deal, the parents would be disregarding their own final ends. To that extent, they would be practically irrational. But at most this amounts to some kind of 'wronging' of themselves. Why should it make them feel guilty towards their child? Why would they feel as if they had done something wrong to their child by relating to her as if she were replaceable?
Since their love is not a reflection on how valuable they believe their child to be -since it is in fact compatible with their love that they think of their child as objectively valueless -it seems that at least qua lovers, the only reason they have for relating to their child as irreplaceable in thought and action is the fact that they happen to find themselves in this particular psychological state, a state which makes them want to do so. In other words, there is no further normative standard that comes along with loving their child that could explain their guilt towards her. 14 11 Cf. my discussion of Frankfurt in Kreft (2021: 205-6). 12 Means are not the only type of non-final end. There are non-final ends that are not valued as means, and yet, their value depends on some other, finally valued end. Kolodny (2003: 150) mentions the example of human remains. 13 One might worry that it doesn't actually capture the subjective aspect: as we saw in Sect. 1, non-lovers might also relate to the beloved as irreplaceable, and one plausible explanation would be that they, too, take the beloved to be a final end. But in that case, there wouldn't be any difference between non-lovers and lovers regarding the beloved's irreplaceability. A possible response on behalf of Frankfurt would be to say that whereas non-lovers relate to the beloved as a final end insofar as they judge the beloved's continued existence and wellbeing to be a final end, lovers relate to the beloved as a final end insofar as they themselves pursue the beloved's continued existence and wellbeing as a final end. I outline this distinction in greater detail in Kreft (2021: 205, 208, 210). 14 Perhaps one could consider some sort of error theory in response: even if lovers do not have any reasons for feeling guilty towards their beloveds for relating to them as replaceable, they might still mistakenly but systematically believe that they have such reasons. In this context, however, this defence would seem ad hoc and not independently motivated.

Relational accounts
I now turn to accounts that keep some key ideas of the quality theory. According to relational accounts, love does imply value judgments, but the judgments in question are about the beloved's relationship with the lover and their particular ways of interacting. Niko Kolodny (2003) argues that to love a person is to believe that one has a valuable type of relationship with them, for instance. More recent examples are Katy Abramson's and Adam Leite's (2011) view that love is a reactive emotion, or Hitchem Naar's (2017) view of love as based on subject-relative reasons.
In all of these approaches, lovers would not be willing to replace their beloveds for persons with similar or even better 'intrinsic' qualities, because their love is a response to what has happened between them and their beloved in particular. The properties relevant for explaining and potentially justifying love are these relational ones. In the following, I argue that such accounts have trouble meeting both condition one and two. With respect to condition two -the moral aspect -the problem is not that they do not introduce any normative standards at all, but that they do not introduce the right kind of standard.
I start with Kolodny's relationship theory. Insofar as relationships are constituted by historical events connecting the relata in question, they are unique to the relata. But we have some kind of unique relationship with many (if not with all) persons and, clearly, not all of these unique relationships explain and / or justify love. Hence, according to Kolodny (2003: 150-1), only particular types of valuable relationships are relevant -the ones that count as romantic relationships, friendships, familial relationships, etc. But if these types of values end up doing the explanatory work, why should lovers not be willing to replace their beloveds for persons with whom they share equally or more valuable relationships? 15 Once more, imagine parents who lose a child. If they have another child at some later point, their relationship to this new child will be equally valuable to the relationship they had with the child they lost. Still, as mentioned in Sect. 1, the second child will not be a compensation for the first one: it is not as if the second child cancels out the loss of the first, in the way a new copy of a book can (sometimes) cancel out the loss of the first. How could Kolodny's theory explain this? The parents are equally well off with regard to their participation in valuable relationships after they have a second child. So the new relationship should compensate for the loss of the first -and it might in fact do that, but that is not the same as compensating for the loss of their child. This remains unexplained, so condition one is not met. 16 It is also unclear whether Kolodny's account meets condition two. Take the parents in the previous example again, who love their child but agree to the replacement deal in a moment of confusion. According to Kolodny, they would deprive themselves and the child of the valuable relationship they share with their child, so they would harm both themselves and the child. However, not every harm constitutes a wrong, so not every harm explains and justifies guilt.
15 Kolodny (2003: 147) addresses a problem that looks similar to this one but is in fact different. It seems to be a consequence of the classic quality theory that lovers would be irrational if they did not love everyone whose qualities are relevantly similar to their beloved's. This is a further reason against this quality theory, and it speaks in favour of Kolodny's account that it does not face this problem. According to Kolodny, lovers should love everyone with whom they share a similarly valuable relationship, which seems to be the right result. However, this is different from the irreplaceability problem. 16 See also Naar (2017: 8) and Matthes (2013: 39, 53) for similar points.
Even if the harm did constitute a wrong, however, for instance because the reasons for inflicting it were insufficient, it is not clear that Kolodny's theory can give the right answer for why. What distinguishes this case from other cases in which people end valuable relationships for insufficient reasons? It seems that his theory cannot explain what is specifically wrong with treating one's beloved as replaceable and why lovers qua lovers would feel guilty about this in particular (rather than generally about having ended the relationship with their beloved for insufficient reasons).
Abramson & Leite (2011) and Naar (2017) offer a different approach. According to them, love is (or is at least in some ways analogous to) a 'reactive attitude' in Peter Strawson's (1962) sense of the term. 17 A paradigmatic reactive attitude is gratitude: we feel and have reason to feel gratitude towards someone if they have done something nice to us, but not if they are just a nice person in general. Similarly, the thought goes, we love and have reason to love another person only if they have acted in certain valuable ways towards us -simply being a person with valuable qualities in general is not enough. So just like gratitude, love is not just a form of valuing of the beloved, but something we in some sense also owe to someone under certain circumstances, or that we should give to them. 18 It is this second aspect that explains the beloved's irreplaceability: in this picture, the beloved is irreplaceable to the lover in the same sense the person to whom we owe gratitude is irreplaceable to us. Just as we owe gratitude to particular persons who have treated us well and cannot pay this debt by giving gratitude to someone else, no matter how qualitatively similar this other person is or how well they have treated us, we owe love to particular persons and cannot pay this debt by giving love to someone else instead -again, no matter how qualitatively similar they otherwise are or in what lovable ways they have treated us. (If this other person has treated us in lovable ways, too, then we owe them love, too. But that just means that they are irreplaceable for us, too.) Since what matters in this picture is what actually happened between two persons, the earlier replacement scenarios are ruled out.
Still, I think this does not capture the right sense in which lovers relate to their beloveds as irreplaceable. In Sect. 1, I argued that lovers value their beloveds as irreplaceable: when they lose their beloved, they grieve (in part) because they have lost something that is of irreplaceable value to them. But if the beloved is irreplaceable to the lover in the same sense as someone we owe gratitude to is irreplaceable to us, we cannot explain why losing the beloved injures the lover in this way. Valuing and owing are different relations, and in this account, the latter carries the explanatory weight. The fact that the lover also values the beloved for having treated the lover in lovable ways is neither necessary nor sufficient for explaining the beloved's irreplaceability here: the owing relation is enough to explain it, and without reference to owing, the account would not fare any better than the initial quality account with respect to explaining irreplaceability. So condition one is not met.
What about condition two? On this picture, if the parents in the earlier example replace Ada for Eva in a moment of confusion, they would fail to give Ada what they owe her -if 17 Abramson & Leite argue that love is a reactive emotion: it is a response to the beloved's virtuous behaviour towards the lover. According to Naar, love is not necessarily directed at virtuous behaviour towards the lover, but all sorts of behaviour towards the lover that the lover finds lovable. See also Protasi (2016: 20) on what she calls 'experiential' properties 'that could not exist or be experienced without the lover having interacted with the beloved'. 18 Abramson & Leite might not want to say that we strictly owe love to our beloveds, but something weaker, namely that we should love the beloved, morally speaking. When I speak of 'owing' in the following, I mean it in a broad sense that includes this weaker claim. not love itself (since they still love her), then loving care and attention. This is a reason to feel guilty. But it does not sufficiently explain the parents' guilt. We can imagine that before the replacement takes place, Ada's parents come to their senses and reverse their decision. In that case, they would not have stopped giving Ada what they owe her, and yet, they would still feel guilty simply for having related to her as replaceable for a moment. 19

Objectivism
An objectivist account such as David Velleman's (1999) explains the beloved's irreplaceability by reference to the beloved's objective end-hood. Velleman agrees with Frankfurt that lovers take their beloveds to be ends in themselves. However, unlike Frankfurt, he thinks that they take them to be objective ends in themselves. On his picture, love is grounded in the same value judgment as respect (in the Kantian sense of Achtung) -namely in the judgment that the beloved is a person, in the sense of a bearer of the value of personhood. Persons qua persons are objective ends in themselves and as such, are objectively irreplaceable. Insofar as love is a relation to the beloved as a person, lovers relate to their beloveds as objectively irreplaceable. This is what distinguishes love and respect from other attitudes: when we relate to others in other ways -as objects of emotions such as joy or fear, say, or as our colleagues, bus drivers, doctors, etc. -we might also relate to them as persons but this is not constitutive of these kinds of relations. By contrast, on Velleman's account, it is partly constitutive of both love and respect that they relate to their objects as persons.
According to Velleman, the only difference between love and respect is that whereas love is a seeing of the other as a person, respect is just the theoretical acknowledgement of their personhood. 'Seeing' is not necessarily meant metaphorically here: even though personhood is not something that could be directly visible, Velleman (1999: 371) takes it to be indirectly visible in the way someone walks and talks, the way they hold themselves, and so on. It also 'disarms our emotional defences' (1999: 361) towards the person seen, and so, fittingly, whether or not we actually come to see someone else's personhood is not under our control ('fittingly', as it makes sense that we cannot control when our emotional defences are disarmed). This explains why we do not always love everyone we respect (even though on his picture, it seems that we would have reason to love everyone we respect 20 ) and it also explains why, unlike respect, love cannot be morally required.
Velleman's account captures something important which the previous two did not: it explains why the beloved is irreplaceable not just for the lovers, but also for non-lovers, as outlined in Sect. 1. The beloved's irreplaceability and the irreplaceability any person has for us qua a person are intimately conceptually connected. It might be somewhat surprising that 19 Perhaps even contemplating not giving one's child what one owes them can seem sufficiently morally problematic to parents to explain their feelings of guilt. However, firstly, it is not clear that this would be an explanation in the sense of making rational sense of their guilt. Secondly, it would mean that relating to their child as replaceable is morally problematic in the same sense as contemplating not giving them what one owes them in other ways and contexts. But again, this does not seem to be sufficient: there seems to be something specifically wrong with relating to the child as replaceable. 20 Harcourt (2009) thinks this is a problematic consequence of Velleman's view. Harcourt argues that it commits Velleman to the claim that, ideally, we would love everyone (even if we are not morally required to love everyone, because we cannot help the way we see or do not see others). But this would mean that in an ideal world, there would not be any space for personal, exclusive love, and according to Harcourt, this would be problematic. The desire account I am proposing in the next section does not suffer from this problem. what explains the beloved's irreplaceability is a property that the beloved shares not just with some but with all persons. But since this property is responsible for every person being irreplaceable, the earlier replacement scenarios are immediately blocked. For a person to be irreplaceable means that they cannot be replaced by anything or anyone, not even other, equally irreplaceable persons. Respecters relate to others insofar as they irreplaceable, and so do lovers.
The account also meets condition two -the moral aspect -, because on this picture, what makes the beloved irreplaceable is itself also of moral value. In Velleman's Kantian framework, we ought to relate to objective ends in themselves as irreplaceable, in a moral sense of 'ought'. If being a lover means actually seeing that the beloved is an objective end in itself and thus objectively irreplaceable, it also implies believing that one ought not to relate to the beloved as replaceable.
The objectivist account depends on a broadly Kantian conception of persons as objective ends in themselves. It is beyond the scope of this paper to develop a proper defence of this conception, and it is not strictly needed for my current purposes. 21 The fact that a lot of us intuitively agree with this conception, as outlined in the passages in Sect. 1 on other people's deaths, and as many of our every day practices suggest, provides a sufficient basis for taking the approach seriously.
The problem with Velleman's account is that it does not meet condition one, i.e. it does not explain the subjective aspect of the beloved's irreplaceability. If love is a seeing of the beloved as a person, as compared to a mere theoretical acknowledgement of their personhood, we cannot explain why lovers grieve over the loss of their beloved in a way nonlovers who nevertheless respect the beloved do not: the distinction between seeing and theoretically acknowledging someone else's personhood does not capture this difference. The difference it captures is analogous to the difference between witnessing a car crash and reading about it on the news. The former is a more intense and shocking experience, an experience that might well disarm our emotional defences, to use Velleman's term. But the grief lovers feel when they lose their beloveds is not just a more intense and shocking form of the experience that the non-lover has. As outlined in the previous section, it is substantively different because it involves a personal injury. It is more as if one would be involved in the crash oneself.
Neither volitional, nor relational, nor objectivist accounts are able to explain both the subjective as well as the moral aspect of the beloved's irreplaceability. Frankfurt's account meets condition one, but fails to meet condition two; the relational accounts do not meet either condition satisfactorily; and Velleman's theory meets condition two, but fails to meet condition one.
I understand persons as independent thinkers and agents. They have a perspective on the world, meaning they have a perspective on what is 'true and good', and they have the capacity to direct their behaviour accordingly. We usually experience other human beings as persons quite naturally, even small babies; it can be difficult to 'snap out' of this way of experiencing them. We sometimes also see non-human animals this way. So we experience others as persons quite independently of what specific cognitive capacities we ascribe to them. Or at least, it seems that the cognitive capacities we believe are required for personhood do not have to be especially advanced. Of course, our experience of babies and (some) non-human animals as persons might not be factive, but that will not matter here. 22 There are several attitudes we can have towards someone as a person: we can simply acknowledge their personhood, and we can also see their personhood in Velleman's sense. But apart from this, I suggest that we can also desire them as a person: we can desire them insofar as they are independent thinkers and agents; that is, we can desire to engage with them as independent thinkers and agents and to relate to them in this fundamental respect.
What is it to desire to engage with someone as an independent thinker and agent? I suggest it is to desire to engage with their perspective on the world: it means, among other things, wanting to understand their fundamental beliefs, values, ends and desires, wanting to be understood by them in return, and wanting to further develop these attitudes together with them. I say 'fundamental' because our perspective on the world is comprised of the attitudes that explain why we see the world in a particular way, and of the desires and ends that ultimately move us, in contrast to relatively superficial beliefs about bus schedules and so on, or relatively superficial desires for, say, ice cream that are easily given up. We desire, as I shall say, to be in 'deep conversation' with them -'deep' because it is about these fundamental attitudes, and 'conversation' instead of 'communication' or 'interaction', in order to highlight that it is a normative exchange about 'the true and the good' rather than just an exchange of information.
To love a person, I propose, is to desire to be in this kind of deep conversation with them. Being involved in deep conversation with another person also means trying to understand 'the world' together with them -after all, it is a conversation about one another's perspectives on the world. So on this picture, love does not only come along with a desire to understand the beloved, but it makes lovers curious in a more general way. This is a Socratic element of the account, and we might fear it means it is overly intellectualistic. Deep conversation can take different forms, however. As mentioned, not just any kind of communication or interaction between two people would count -it needs to be about one another's fundamental attitudes towards the world and it is a serious attempt to develop these attitudes together. But it does not have to be verbal in a way we might imagine a classic conversation. It can also be emotive or physical in the sense of involving gestures, looks, and touch. Sometimes, our fundamental attitudes are only semi-conscious anyway, and in that case gestures, looks and touch might even be better than words at conveying them to one another. In certain situations, throwing a baby up in the air and catching it, or looking at a beetle in the grass together, or having sex can all be forms of deep conversation. 23 22 See Kittay (2005) for a defence of a conception of personhood independent of specific cognitive capacities. It would also be worth exploring whether one can conceive of being a thinker and an agent independently of specific cognitive capacities. 23 In Anna Karenina, there is a scene in which Kitty's nurse Agafya Mikhailovna tells Kitty that her son Mitya recognised her (i.e. Agafya) for the first time that day, and Kitty smiles in response: 'She smiled We might conceive of the different types of interpersonal love as desires for different forms of deep conversation: romantic love could be seen as a desire for an all-encompassing conversation, involving both speech (in the more narrow sense of the term) and touch; close friendship as a desire for a more restricted form of deep conversation; parental love as a desire for a deep conversation that is attuned to the particular needs of the child's developing perspective on the world, and so on. Even within the course of a particular love relationship, the form deep conversation takes might change over time.
This does not sufficiently capture love yet. We would need to add that love is a noninstrumental desire for deep conversation, for instance. Furthermore, the desire must be for an open-ended conversation: if the desire is to be in deep conversation for a day or a night only, it would not count as love. 24 (In fact, we might even think that lovers hope that there may never be an end -love, while it persists, wants to stretch out into the future without limit. 25 ) Finally, the desire is not going to be unimportant in the sense that it does not really matter to the lover whether it gets satisfied or not. The desire to have ice cream for desert is usually unimportant -whether or not we get ice cream does not usually matter much to us, and so it tends to be relatively easy to deal with the desire being frustrated. But to count as love, the non-instrumental desire for an open-ended conversation with another person about their perspective on the world will be one of the few desires we really care about and hope to be satisfied. And if that is impossible, for example because it is not reciprocated, it is a legitimate reason for pain and sadness. 26 We would need to further specify these conditions. But for my current purposes, what is important is that, if we conceive of love as a desire for someone as a person, we can explain both the subjective as well as the moral aspect of the beloved's irreplaceability. Just as in Velleman's picture, lovers relate to their beloveds as persons here, and this explains why they believe that they ought not to treat their beloveds as replaceable in a moral sense of 'ought'. But unlike in Velleman's account, lovers do not just see but desire their beloveds as persons, and this explains why they experience the loss of their beloved substantively differently from the way in which non-lovers experience the beloved's loss. Because of their desire, lovers are personally affected by the beloved's loss in a way non-lovers are not. The beloved is objectively irreplaceable as a person to lovers and non-lovers alike, but because the lover wants something from the beloved -because they desire to be in deep conversation with them -the lover is subjectively vulnerable to this objective irreplaceability. because (…) she knew in her heart that he not only recognized Agafya Mikhailovna but knew and understood everything, knew and understood much else that no one knew and she, his mother, had herself learned and begun to understand only thanks to him. For Agafya Mikailovna, for his nanny, for his grandfather, even for his father, Mitya was a living being who required only maternal care; but for his mother he had long been a moral creature with whom she had a whole history of spiritual relations.' (Tolstoy, 2006(Tolstoy, [1873: 783) This could be read as an illustration of how one can be in deep conversation with a baby, where words are still irrelevant. 24 Although this does not rule out the possibility of being in love for a short period -one night, say. What it means to be in love for one night does not mean desiring to be in conversation for only a night, but to experience a desire for open-ended, deep conversation, albeit a desire that only lasts for one night. The time limit is not part of the content of the desire, in other words. 25 See Marušić (forthcoming) on the endlessness of love.
Apart from meeting both conditions, this account also has other advantages. For instance, since deep conversation can only take place if both partners want it, the account can explain why love typically comes along with a desire to be reciprocated. It also leaves room for the possibility of unrequited love, however: the desire for reciprocation might not be fulfilled. 27 The account also combines some of the insights of the views discussed in the previous section: lovers take their beloveds to be ends in themselves here, as in Frankfurt's account; and insofar as they relate to their beloveds as persons, they essentially also relate to them with the kind of personal stance in which the Strawsonian reactive attitudes make sense. But since love is understood as a certain kind of desire here, this account is phenomenologically more adequate than the others. For wanting to be close to the beloved in these ways seems to be a crucial part of love that the others do not capture. Lovers hope for a particular sort of shared future with their beloveds, a joint development of their perspectives on the world, and love is not necessarily directed at a shared past as in Kolodny's account.
It has been argued that we can love others without wanting to be close to them. Velleman (1999: 335), for instance, writes that 'it is easy to love someone whom one cannot stand to be with. (…) This meddlesome aunt, cranky grandfather, smothering parent, or overcompetitive sibling is dearly loved, loved freely and with feeling: one just has no desire for his or her company.' 28 Depending on how we read 'desire for his or her company', this is compatible with my account. One can desire to be in deep conversation with someone in the above sense but not desire to be in physical proximity or even to be in touch very often. Sometimes, we can love someone and at the same time desire not to be in touch with them in any way, but I think this only happens when we have conflicting desires. One possible reason for this conflict might be that we believe that we ought not to give in to our desire for the beloved.
So there are two types of relevant cases here: in one case, we desire to be in deep conversation, want to give in to and follow the desire, but do not necessarily desire to be in constant touch with them. The conversation we desire might just not be of that form. In another case, we also desire to be in deep conversation, but we are conflicted. In the latter case, unlike in the former, the desire not to be in touch with the beloved is contrary to one's love, it tries to outdo the desire that comes along with love. But not wanting to give in to one's love is still compatible with being in love on my account.
The only thing that is not compatible with it is not desiring to be in deep conversation with someone, that is, not desiring to understand their perspective on the world and be understood by them in return, and not wanting to develop together in this respect. If we do not really care what our meddlesome aunt or our cranky grandfather thinks, feels and desires in the fundamental sense spelled out above, then we might still be fond of them and concerned for their wellbeing, but on my account we do not really love them and we are not vulnerable towards them in the way lovers are towards their beloved. 29 (Sometimes, we are 27 See Protasi (2016) on why a theory of love should leave room for the possibility of unrequited love. 28 See also Martin (2015). 29 In Yongming Han's (2021) account, love is the final desire for the beloved's wellbeing (see p. 14, et al.). Wouldn't this suffice to explain the lover's vulnerability towards the beloved? No, because it seems to me that we can have Han's sort of desire even for people we do not love and towards whom we do not feel vulnerable in the required sense. In fact, arguably, we have a final desire for the wellbeing of everyone we respect as a person, since this is implied in valuing them as ends in themselves (although valuing them as ends does not necessarily mean that we desire that we be the ones to help them pursue their wellbeing). In order to explain also unaware of our love for someone and we only realize when they are gone that we loved them, because we are struck by our grief for them.) Finally, we might ask why we love the persons we love and not others. Why do we desire to be in deep conversations with these particular people, rather than others whom we also respect as persons? Since this is a separate issue from the one discussed in this paper, I am not going to give a detailed and systematic answer here. I am sympathetic to the view that this desire does not arise for any specific reasons, at least not for reasons that go over and beyond the reasons we have for respecting other people (i.e. that we perceive them to be ends in themselves on account of their personhood). 30 Instead, we can consider certain psychological explanations: perhaps it is enough to say that our desire for deep conversation with certain persons is explained by the ways in which we have learnt to communicate, how well we can read someone else's expressions and who is consequently able to 'open and move' us. When we do have this desire for someone, however, we start attending to and caring for them in the ways lovers typically do.

Conclusions
I have argued that in order to explain why and in what sense lovers relate to their beloveds as irreplaceable, a theory of love has to explain both the subjective and the moral aspect of the beloved's irreplaceability. I argued that three important approaches to love and irreplaceability fail to explain either one or both of these aspects: volitional theories cannot explain the moral aspect of the beloved's irreplaceability, relational accounts offer the wrong kind of explanation for both aspects, and the objectivist account fails to explain the subjective aspect.
As an alternative, I introduced an account according to which love is a desire for the beloved as a person. Just as on the objectivist approach, it conceives of love as a form of relating to the beloved as an objectively irreplaceable person -love is a sister attitude to respect here. But instead of merely seeing, it desires the beloved as a person. Given an understanding of persons as independent thinkers and agents who have a perspective on the world, on what is true and good, this means that love is a desire for what I called 'deep conversation' with the beloved. This account can explain both the subjective and the moral aspect of the beloved's irreplaceability. It is also attractive independently of this: while it takes on and is able to explain important insights of the previous accounts, it is phenomenologically more adequate. 31 Funding Open Access funding enabled and organized by Projekt DEAL. the vulnerability that is typical for lovers, the desire that is essential to love cannot be wholly selfless. Lovers qua lovers also want something for themselves. 30 In that sense, I agree that love has non-deontic reasons. And I agree with Han (2021) to the extent that I do not think the selectivity of love necessarily pushes us towards a reasons-view of love, especially not if these reasons are understood as deontic. 31 My thanks to Felix Koch, Berislav Marušić and Andrew Stephenson for invaluable comments on earlier drafts. For very helpful discussion thanks also to various audiences at the Einstein Ethics Group and at HU and FU Berlin. Finally, my thanks to two anonymous reviewers for their insightful comments and suggestions.