Before embarking on a philosophical study of suicide, it may be helpful to attempt at least a preliminary definition of it.  A definition that comes to mind is the following:

A. Suicide is any form of self-killing, where self-killing is understood as acting in  such a way as to bring about one's own death.
 Problem: consider the following three cases:

  1.  Jack gambles away his fortune.  So, he shoots himself.
  2.  Joe climbs the Alps without a guide and dies (accidental death).
  3.  Jim unwittingly drinks cafeteria coffee and dies.

Presumably, we agree that (1)-(3) are cases of self killing, but only (1) is a case   of suicide.  Hence, the definition is too wide.

B. Durkheim's definition of suicide:
Suicide is the death resulting directly or indirectly from a positive or negative act  of the victim himself, which he knows will produce this result.

4) Jim knows he'll be shot unless he betrays the underground; he doesn't betray and   is executed.
Presumably, (4) is not a case of suicide because Jim doesn't intend to die and doesn't see his death as a means not to betray.

Consider now these cases:

5) Joe takes poison and dies in order not to reveal secrets.

This is a case of suicide because Joe intends to die not to reveal secrets; that is,  he views his death as a means to achieve a goal (keeping the secrets), and known  means to intended ends are themselves intended.
NOTE: Some, e.g., Beauchamp, deny this is a case of suicide because Joe is coerced and consequently doesn't act of his own free will (his act is not his own). On this view, neither Socrates nor Seneca committed suicide.

 6) Jack throws himself on a grenade to save his buddies and the explosion kills him.

 Presumably, this is not a case of suicide because

C. Another definition of suicide: X commits suicide iff:

  1. X acts (or refrains form acting) in such a way as to bring about his own death.
  2. X intends by those actions to bring about his own death either because  he   wants his own death per se, or because he wants something which he  thinks can   be caused only by his death (not merely by the act which also causes his death as   a foreseen but unintended consequence).

The definition allows:



Before investigating suicide, a few points are also worth noticing:

         It's far from clear whether suicide is a cowardly act, as it is often claimed. For one thing, it take some courage to commit suicide because it requires overcoming a natural instinct for self-preservation. For another, in some situation involving extreme suffering continuing life would be (perhaps foolishly?) heroic. But morality does not require us to be heros at all costs.

         It's not clear whether the commandment "Don't murder" prohibits suicide.In many circumstances we are morally permitted to kill, as in war, in self-defense, in protecting life and limbs; the point is that not all killing amounts to murder.If I am allowed to kill you if I know that otherwise you're going to inject me with some horrible disease, why should I not be allowed to kill myself if I have that horrible disease?

         The issue of whether suicide is morally permissible is different from that of whether suicide is reasonable. Note that there are many unreasonable and stupid things that can be morally permissible.

         It is simply false that people who commit suicide are mentally ill, although no doubt some (and perhaps many) suicides are the result of mental illness. In many cases, the decision to commit suicide is reached with proper information and good reasoning.

         The idea that one should keep on living at all costs because there's always hope that things will get better is very problematic. Sure, it is possible that tomorrow someone will discover the cure for my horrible disease and give it to me. But our reasonable decisions are made on the basis of what is probable, not merely of what is possible. It's certaily possible that tomorrow I'll win the lottery, but it would be unreasonable of me to start making debts today because what is possible need not be probable.

         Although some, perhaps many, cases of suicide do show disregard for the feelings or the interests of family and friends, it's simply false that all do. Sometimes people commit suicide with the agreement of family and friends, and sometimes they take into due consideration not only their own feelings and interests but also the ones of others. Hence, suicide need not be a selfish act any more than most other acts.



Aquinas on suicide.

It's wrong to commit suicide (unless commanded by God!)  because:

Objection: What does "natural" mean? As the inclination to commit suicide is not uncommon, whay is it not natural?
Reply: "natural" as normative notion stemming from an Aristotelian (perfectionist) consideration of humans: one ought to strive for happiness (the actualization of human capacities), and suicide prevents that.
Duplication: but then the good is happiness, not life per se, and if one's life is wretched and with no hope for happiness, the reply fails.


Thought Question: how basic are property rights?Do they trump avoidance of severe pain and suffering?Can you think of some examples?

Kant on suicide.

For Kant, the intention to kill oneself constitutes suicide.  He provides two order of arguments against the permissibility of suicide, secular and religious.   The latter dependent on the former: God forbids suicide because it is wrong, not vice versa.

A) Secular arguments

Kantís point applies, if at all, to the first one.  But the spring of suicide can be the second.

Thought Question: Does Kant fail to appreciate the importance of moral luck?

K. distinguishes between one's life and one's humanity; duty towards the former is conditional, towards latter absolute.  But suicide at times originates in respect for one's humanity (personhood), as in the case of suffering or living in chains.  See, e.g., Seneca's letter 70 to Lucilius, or even Kant's remarks on Cato's suicide (the only case about which he seems in doubt)
Reply: One's humanity cannot be diminished or stripped away because morality is totally autonomous (one can always be moral in Kantís view).
Duplication: It is far from clear that this is so.  Consider cases of forced administrations of drugs, brain-washing, concentration camps, mental degeneration, etc.  Ultimately, Kant fails to appreciate the importance of moral luck.


B) Religious arguments:

Hume on suicide.

Superstition and our natural fear of death make our views on suicide muddled.  It's the task of philosophy to free us from confusion and show that suicide may be free from all imputations of guilt and  blame because it is not a transgression of our duties towards God, society, or ourselves.

1. Suicide is not a transgression of duty towards God.
God is the creator of a system of inanimate and animate creatures which act on the  basis of immutable laws.  Human life, like everything else, is subject to natural  laws, and diverting a few ounces of blood from their usual course is no more an  encroachment on providence, or a disturbance of the order of creation, than  diverting a river. It's arbitrary to allow the former and condemn the latter.
NOTE: H's point is that human life, like most everything else, is rightly subject to human prudence.

2. Suicide is no transgression of duty towards society
Hume presents several arguments:

Thought Question: do you think there is a duty to commit suicide to avoid pain and suffering to others?

3. Suicide is no transgression of duty to oneself.  Age, misfortune, sickness can make life worse than death.


Suicide and Paternalism

It is one thing to believe that suicide is morally unjustifiable, it is another limit the freedom of action of one who wants to commit suicide.  We value rational agency, and one of the manifestations of rational agency is acting in accordance with one's own conception of the good (i.e., autonomously).  In other words, the fact that an agent can act autonomously is good.  It follows, then, that one might be morally required to uphold one's legal right to do what's morally wrong if the morally wrong act is a manifestation of autonomy and compatible with it.

Note: this rules out things like self-enslavement.

Paternalism is the limitation of a person's liberty of action or information for the sake of that person's welfare or needs.  Since paternalism restricts autonomy, it requires a justification (it's guilty until proven innocent, as it were).
It helps to distinguish two types of paternalism:

  1. Weak paternalism, namely interference in case of:
  2. Strong paternalism, namely, interference when the agent seems to have made a decision to commit suicide on the basis of reasonable use of the relevant  information, and when all of one's values are taken into account.

Thought Question: to what extent is an appeal to future values reasonable?For example, I may know that if I donít kill myself my values will become thus and so as Iíll adjust to my new state, and at that point Iíll judge favorably my decision to keep on living.But suppose that now I donít want to be the type of person Iíll become if I keep on living.What should I do?


While weak paternalism is justifiable because it does not impinge on autonomy, strong paternalism is much harder to support and probably has to be rejected.