How could she do it to her friends and to her family and to the rest of those who needed her? How could such a smart kid commit such a dumb act and be lost to us? There is no place for this kind of thing in an ordered world---it should never happen. Why, without asking any of us, would this beloved young woman just go ahead and take herself away?
Those who characterize suicide as "selfish" tend to focus, as Nuland does, on its effect on those left behind, rather than on the pain of the suicide, and whether it is fair to expect her to continue living so that her friends will not be deprived of her company. (Note that it is also common for them to characterize the suicide in demeaning ways, such as "dumb," "stupid," or "cowardly.")
Duty, Self-Interest, Reasonable Generosity, and Selflessness
It is important to figure out what we mean when we call an act selfish. One possibility is that "selfishness" occurs when someone violates a duty to another. As I will explain, this is not the sense in which we usually use the term "selfishness." In addition, even under this definition, the act of suicide is not in violation of a duty.
Selfishness does not entail the violation of a duty. For instance, we might speak of someone as "selfish" if he does not share his popcorn with his friend. He owes no duty to share his popcorn, and the friend has no right to the popcorn, but we may nonetheless properly characterize his failure to share as selfish. "Selfish" must therefore have another meaning.
However, even though we must look elsewhere to figure out whether suicide is selfish, we can briefly touch on the question of whether suicide entails the violation of a duty. The identification of continued life as a duty must mean that, on the other side, others have a right to our continued life. However, it is very strange to think of someone as having a right to our company, care, or even presence in the world (with the exception of our children, as I have explained before). In most cases, bodily autonomy and self-determination are held to be more fundamental rights than any "right" to be free from the emotional pain of someone's absence. Given that bringing someone into existence is a serious wrong, I am not sure what distinguishes the suicide case from the escape-from-slavery case. In both cases, the agent removes himself from a horrible situation after a serious wrong has been done to him. In the process, he harms those with an interest in his remaining in the horrible situation (friends and family for the suicide, the slave owner for the escaping slave). But it would be very strange to say that the interests of the people left behind are sufficient to create a duty not to leave the horrible, unfair situation.
Taking Self-Interest as More Important than the Interests of Others
Another candidate for a definition of "selfish" might be taking the interests of oneself as more important than the interests of others. By this definition, we are selfish if we ever put our own interests ahead of those of others. But this definition must also fail, as it gives ludicrous results. Mainly, the definition fails to take into account that the interests of oneself and the interests of others may be of objectively different strengths. If I suffer a serious fall and yell to my neighbor to help me, I am putting my interests (in summoning an ambulance) ahead of my neighbor's interest (in not being bothered with my problem). But it is ridiculous to call my action selfish. Similarly, if I end a romantic relationship because I no longer love the other person, I am putting my interests in being free from a loveless relationship ahead of his interests in having my continued company. But, again, rarely would we characterize this personal decision as selfish. In fact, it would be selfish of my neighbor to refuse to help me (assuming he hasn't anything more important to do), or for my lover to demand that I remain in a loveless relationship. Therefore selfishness must refer to making a wrong judgment about the relative strengths of my own interests and that of others. One way to say this is that it is selfish, all things considered, to put a minor interest of my own ahead of a serious interest of someone else. Another way to put it, and one that captures more dimensions of the problem, is to say that it is selfish to fail to show that generosity that can reasonably be expected of people in a particular relationship.
When someone fails to share his popcorn with his friend, he is not violating a duty, but rather failing to show that level of generosity that can be reasonably expected of someone in a friendly relationship. The generosity that can be reasonably expected must take into account the magnitude of the sacrifice that is demanded, and the strength of the interest in whose name the sacrifice is to be made. If the sacrifice is slight or even roughly equal to the interest served, then, depending on the relationship, it might be selfish not to make it.
And this is the essential disagreement as to the selfishness of suicide: whether it is reasonable to expect someone to continue to live a miserable life for the sake of the feelings of his friends and family. I suspect that most people, like Dr. Nuland, cannot imagine that life could be so bad that one's suffering could outweigh that of one's friends left behind. These are the people that David Benatar characterizes as "cheery" (he means it as a swear). It may be impossible to accurately measure or assess the difference in suffering between the would-be suicide who remains alive despite wanting to die, on the one hand, and the friends and family deprived of the deceased suicide, on the other (but see my previous post on qualia of happiness). Almost certainly, it varies. (An interesting outcome of this way of looking at things is that, by this definition, the suicide of a person with no friends or relatives is not selfish at all, even if he is only experiencing slight suffering, whereas the suicide of a person with many friends and relatives may be very selfish, even if he is suffering severely.) But certainly it is a bit rich to assume that, in all cases, the suffering of the would-be suicide is outweighed by the possible suffering of his friends and family from being deprived of his company. In fact, in many cases it must be that it is selfish - even indecent - for a suffering person's friends and family to expect him to continue living, if his suffering is so serious that it outweighs their interest in his continued company.
Some people who feel that their lives are not worth living, and who would very much like to die, nonetheless continue living for the sake of saving their friends and family the sorrow that their suicide would entail. Is this merely what is expected of them? Or might we characterize their action in continuing to stay alive as particularly selfless? If selfishness is failing to exhibit even a reasonable minimum of generosity, selflessness must be exhibiting an especially high level of generosity, much more than is ordinarily expected. If one's suffering is so great that one prays for death every day, and yet continues to live to spare one's friends and family the pain of the lack of one's company, we must certainly say that for that person, merely living is a selfless act.
The Trap of Existence
Suicide is not easy, practically or ethically. One reason to avoid having children, as Benatar points out in his conclusion to Better Never to Have Been, is that even if one's child suffers so much that he wishes to die, he may be prevented from ending his suffering by generous ethical considerations, such as the worry that his suicide will cause pain to those around him. Benatar refers to this as a kind of trap: after suffering the harm of being brought into existence, we cannot end it without causing still more harm in the horrible, blighted, wretched universe into which we have been cast.