Suicide is a difficult subject for many people. This is presumably partially down to the fact that suicide seems so alien or impossible to really imagine. What person in their right mind would do such a thing?
What is suicide?
For my purposes: suicidal behaviour is behaviour whose primary goal is to end the life of the subject. This means that some things that might be considered suicidal by some, are not. There are some classic examples here. One is the example of throwing ones self onto a live grenade. This action might be suicidal, but if the primary goal is to save the lives of comrades, then by my usage here it is not.
Furthermore, suicide attacks such as Kamikaze, suicide bombing, or the September 11 attackers are not suicide by my definition. They all have alternative primary goals. The death of the subject is pretty much incidental to those goals. Sometimes it is a desired side effect, other times an undesired one.
But I'm going to be principally talking about suicide where one's own death is the primary goal.
When is it rational?
To the left is a graph depicting a hypothetical life. The x-axis is time from birth to death. The y-axis is a measure of happiness of some sort. It is a sum of all the pros and cons for being alive at that given moment. When the line is above the axis, life is good and worth living. When the line is below the axis, life is hard and not worth living.
I think everybody would intuitively agree, however, that just because life is tough at period B, suicide would not be a rational response. It is a relatively short period of time, and it is followed by an overwhelmingly positive life for an extended period of time.
However, at the start of period D, life becomes bad, and is going to get worse and worse and worse ending only at the subject's death. The most obvious explanation for this would be a terminal illness of some kind. We might argue, that if a subject knows the shape of their graph, that it might well be rational to kill themselves at or around stage D.
Is it irrational?
So how can it ever be rational? How can we be sure of our projections into the future to make the decision to end it once and for all? With emphasis on the 'for all'. As ever we have to turn to projected probabilities. If we are acting rationally, we need to estimate the probabilities for the future.
Obviously mental health issues will distort our probabilities, which is why mental illness can be so life threatening.
But what if the subject is very sick at stage B, with a physical illness? One that is so bad it makes one wish one was dead. The subject should work out what are the chances of recovery, and what are the prospects for life once recovery is complete. Hopefully, they will see the first graph as being a realistic possibility and will therefore not kill themselves.
But physical discomfort can be very coercive, and can affect our rational minds just as much as mental anguish.
Is it moral?
Let's re-examine stage B. At stage B it might still be rational to kill one self, though it might not be rational to commit suicide (remember my distinction?). For example, if one knew a secret that if revealed would cost many lives it might be moral to kill oneself to avoid revealing that secret if stage B represents a torture sequence (even knowing that stage C will be swell for us). This would be with the primary intention of saving lives, though, so it would not be the kind of suicide I'm discussing.
Can it ever be moral to commit suicide? Well, why is it immoral? I'm not going to entertain the 'subverting God's will' argument here. I think Hume covered that quite well. If you are curious you can search for Hume's Of Suicide to get the rebuttal to that kind of argument.
There are some obvious moral concerns though: What if you have dependents? What about your other duties and obligations?
These are all difficult issues to resolve, but I think that a moral subject can in principle put their affairs in order to minimize the harm their suicide might otherwise cause. And I think this all lies in tension with our right to life as we see fit (including its voluntary termination). Since suicide is death with consent, I cannot find it intrinsically immoral.
Society needs to adjust to account for this view, and I think it is doing - but slowly. Assisted suicide is becoming something that is accepted morally. For the immediate future, I think that people who want to die, who aren't terminally ill, will be considered mentally ill and thus society will resist their rights to die.
But mental anguish can be as bad as physical anguish, so if it is moral to let someone die to avoid pain, loss of dignity or other suffering - I think a case can be made to allow the mentally ill to die too. Naturally, we would want to try and help the mentally ill person have a good life instead of dying - but that isn't necessarily possible. Today, seriously mentally ill people that would rather die than continue living the way they do are forced to take suicidal actions which are uncontrolled and can result in greater suffering.
It's not an easy subject, but it is better for it to be talked about - than for it to be ignored. Lives are at stake. I recommend, as a starting point for anyone interested, to examine Stanford's Encyclopedia of Philosophy entry on Suicide. It goes into much greater depth than I have been able to.