IE. The Right to have One's Life Saved
There is no such right as there is no corresponding moral obligation or duty to save a life. This "right" is a demonstration of aforementioned muddle between morally commendable, desirable and decent ("ought", "should") and morally obligatory, result of other people's rights ("must").
In some countries, obligation to save life is legally codified. But while law of land may create a LEGAL right and corresponding LEGAL obligations - it does not always or necessarily create a moral or an ethical right and corresponding moral duties and obligations.
IF. The Right to Save One's Own Life
The right to self-defence is a subset of more general and all-pervasive right to save one's own life. One has right to take certain actions or avoid taking certain actions in order to save his or her own life.
It is generally accepted that one has right to kill a pursuer who knowingly and intentionally intends to take one's life. It is debatable, though, whether one has right to kill an innocent person who unknowingly and unintentionally threatens to take one's life.
IG. The Right to Terminate One's Life
See "The Murder of Oneself".
IH. The Right to Have One's Life Terminated
The right to euthanasia, to have one's life terminated at will, is restricted by numerous social, ethical, and legal rules, principles, and considerations. In a nutshell - in many countries in West one is thought to has a right to have one's life terminated with help of third parties if one is going to die shortly anyway and if one is going to be tormented and humiliated by great and debilitating agony for rest of one's remaining life if not helped to die. Of course, for one's wish to be helped to die to be accommodated, one has to be in sound mind and to will one's death knowingly, intentionally, and forcefully.
II. Issues in Calculus of Rights
IIA. The Hierarchy of Rights
All human cultures have hierarchies of rights. These hierarchies reflect cultural mores and lores and there cannot, therefore, be a universal, or eternal hierarchy.
In Western moral systems, Right to Life supersedes all other rights (including right to one's body, to comfort, to avoidance of pain, to property, etc.).
Yet, this hierarchical arrangement does not help us to resolve cases in which there is a clash of EQUAL rights (for instance, conflicting rights to life of two people). One way to decide among equally potent claims is randomly (by flipping a coin, or casting dice). Alternatively, we could add and subtract rights in a somewhat macabre arithmetic. If a mother's life is endangered by continued existence of a fetus and assuming both of them have a right to life we can decide to kill fetus by adding to mother's right to life her right to her own body and thus outweighing fetus' right to life.
IIB. The Difference between Killing and Letting Die
There is an assumed difference between killing (taking life) and letting die (not saving a life). This is supported by IE above. While there is a right not to be killed - there is no right to have one's own life saved. Thus, while there is an obligation not to kill - there is no obligation to save a life.
IIC. Killing Innocent
Often continued existence of an innocent person (IP) threatens to take life of a victim (V). By "innocent" we mean "not guilty" - not responsible for killing V, not intending to kill V, and not knowing that V will be killed due to IP's actions or continued existence.
It is simple to decide to kill IP to save V if IP is going to die anyway shortly, and remaining life of V, if saved, will be much longer than remaining life of IP, if not killed. All other variants require a calculus of hierarchically weighted rights. (See "Abortion and Sanctity of Human Life" by Baruch A. Brody).
One form of calculus is utilitarian theory. It calls for maximization of utility (life, happiness, pleasure). In other words, life, happiness, or pleasure of many outweigh life, happiness, or pleasure of few. It is morally permissible to kill IP if lives of two or more people will be saved as a result and there is no other way to save their lives. Despite strong philosophical objections to some of premises of utilitarian theory - I agree with its practical prescriptions.
In this context - dilemma of killing innocent - one can also call upon right to self defence. Does V have a right to kill IP regardless of any moral calculus of rights? Probably not. One is rarely justified in taking another's life to save one's own. But such behaviour cannot be condemned. Here we have flip side of confusion - understandable and perhaps inevitable behaviour (self defence) is mistaken for a MORAL RIGHT. That most V's would kill IP and that we would all sympathize with V and understand its behaviour does not mean that V had a RIGHT to kill IP. V may have had a right to kill IP - but this right is not automatic, nor is it all-encompassing.
III. Abortion and Social Contract
The issue of abortion is emotionally loaded and this often makes for poor, not thoroughly thought out arguments. The questions: "Is abortion immoral" and "Is abortion a murder" are often confused. The pregnancy (and resulting fetus) are discussed in terms normally reserved to natural catastrophes (force majeure). At times, embryo is compared to cancer, a thief, or an invader: after all, they are both growths, clusters of cells. The difference, of course, is that no one contracts cancer willingly (except, to some extent, smokers -–but, then they gamble, not contract).