When speaking of "causing", "risking" and "allowing the death of other people" or "of the bodies of other people", some might immediately associate these terms with a descending scale of wrongness. Causing someone else's death, or killing, would then be worse (that is more wrong) than risking it, and risking someone else's death would, in turn, be worse (more wrong) than allowing it. Those believing this to hold in general are in error, however. In the event that the beings we are speaking about are persons, it may be worse to cause another person's death than to risk it, but the fact that allowing another person's death is not wrong has nothing to do with a descending scale but everything with the nonactivating character of the extrinsic duty concerned. Those who cause another person's death against 'er will do interfere in the gravest way possible and those who risk this other person's death risk interference, but those who allow the other person's death do not allow interference (unless the other person is involuntarily killed by a third person): they simply do not interfere, which is their extrinsic right (even when a person is involuntarily killed by a third person, albeit a very questionable attitude to take in such a case). Now, if a person asks to be killed there is nothing extrinsically wrong in killing 'im in accordance with 'er express wishes after having taken every precaution to ensure that the decision is a free, personal one. Causing 'er death is then even a better way to fulfil such a wish than merely risking 'er death. And it is in this case the act of not allowing 'er death which would be a flagrant violation of the person's discretionary right to live and to die.

A person who requests to be killed painlessly on account of 'er distressing, physical and/or mental state, because 'e is not able to do this 'imself, is someone asking for voluntary active euthanasia. Such euthanasia is called "active" since it requires an action, namely that someone (a doctor, for instance) causes 'er death; passive euthanasia, on the other hand, requires a nonaction, namely that no-one tries to postpone the death of the person concerned or 'to prolong the act of dying'. Being termed "voluntary" for obvious reasons, it should be distinguished from both 'involuntary' and 'nonvoluntary' euthanasia. Involuntary euthanasia is the act or practise of intentionally killing, or letting die, someone who is ill or injured, or whose future well-being is threatened, in disregard of 'er own views but with the motive to serve 'er own interests. Nonvoluntary euthanasia is the act or practise of intentionally killing, or letting die, an ill, injured or threatened sentient being which is not in the position to have or to express, and which has not expressed, any view on the matter, with the motive to serve its own interests. Voluntary and involuntary euthanasia can only apply to persons or their bodies, nonvoluntary euthanasia may also apply to sentient beings with which one has a special relationship (like domestic animals).

Nonvoluntary euthanasia is not related to personhood, and the killing of happiness-catenal (or living) beings must in this context be judged by the standards applied to killing happiness-catenal (or living) beings as discussed in the previous division. Involuntary euthanasia is a form of killing or not saving people, or their bodies, against their will and will be discussed later in this division. Voluntary euthanasia is governed by the rules of the extrinsic right-duty constellation (like involuntary euthanasia) and, consequently, the difference between passive and active, voluntary euthanasia is significant. Whereas passive voluntary euthanasia only requires that one allow another person to die, active voluntary euthanasia requires that one cause 'er death (or that of 'er body) oneself. If this is done, the person's right is not violated, because one has 'er permission (by definition), but whether it should be done does, strictly speaking, not depend on the person's own wishes. And if one thinks that it should not be done, it is also every person's right to refuse cooperation, that is, to refuse to perform the act of euthanasia.

Whether one is allowed to or not allowed to kill other people, or their bodies, is in the first place a question of extrinsic rights and duties; whether one should or should not do this a question of intrinsic rights and duties. As soon as intrinsic rights and duties come up for discussion, however, we must look at people, or their bodies, as happiness-catenal beings or as living beings. It is then that we should painlessly kill a person as a happiness-catenal being if 'e is bound to suffer a lot from a painful and incurable disease, and under such conditions that the side-effects to other happiness-catenal beings are nonexistent or minimal. (But this should not be done if the person as a hapiness-catenal is only not going to lead a happy life anymore, without definitely having to experience much more pain than pleasure.) As a living being the life of a person is not worth living anymore if 'e is pining away due to a disease which destroys more and more of 'er body and its parts. When both considerations (that is, that of the happiness-catenary value and that of the value of life) point in this direction, one should evidently assist in an act of voluntary euthanasia. If they both point in the opposite direction one may have the extrinsic right to cause the person's death, but then it would still be wrong according to the neutralist doctrine. But the person's own wish is indirectly also of great import from the doctrinal angle, because if 'e wants to die, it is more likely that 'e suffers unbearably and that no future happiness will outweigh 'er pains. Other things being equal this is a reason to validate 'er request for euthanasia.

The definition of euthanasia (act or practise of intentionally killing, or letting die, a person or sentient being that is ill or injured, or whose future well-being is threatened, with the motive to serve its own interests) will probably be attacked for being vague. Thus it might be argued that being ill and a being whose future well-being is threatened admit of different interpretations. This criticism is certainly correct, but can only lead to terminological differences. It does not effect our normative considerations. Firstly, on the metadoctrinal model, a person may give permission to kill or use 'er body regardless of 'er being sick or of 'er well-being being threatened or not. And secondly, on the doctrinal model, if a happiness-catenal or living being is not really sick, or if its well-being is not really threatened, this must influence the decision whether to kill this happiness-catenal, or living, being or not. The procedure to reach this decision does by no means depend on the definition of euthanasia, let alone on its vagueness. It is rather the other way round: if it is believed that something or someone who has not expressed 'er will to stay alive should be killed, then people would rather call this killing "euthanasia".

Another charge of vagueness as regards euthanasia might be that the killing must take place 'with the motive to serve the interests' of the sentient being concerned. This objection is mistaken tho. The concept of motive is not vague in itself; it may only be hard to establish what the real motive is. If the motive to kill or to have killed, say, someone from whom the killer inherits all possesions, is only the killed person's money, then it can easily be pretended that the motive is or was to serve that person's own interests, if the killing would indeed save 'er own interests. (A reason why important decisions like these must not be taken exclusively by those 'most closely affected' unless they do in no way benefit personally from a decision to perform the act of euthanasia.) Such a motive would be a very wicked one, but in the case of voluntary euthanasia it is the person requesting 'er own death who has to take such possibilities into account.

Just as in the case of infanticide, so some theorists use a slippery slope or wedge argument against euthanasia, especially against the decriminalization (or 'legalization') of active euthanasia. The 'logical' interpretation of this argument is that once the all-important first step has been taken to kill human life, there would be no good reason for not accepting additional practises which are plainly unacceptable, and therefore the first step had better not be taken. This, of course, is rubbish, even if we read for "human life", "the life of a person". As has been replied elsewhere already, there is a rational ground for distinguishing between the person 'in agony who wants to die and other cases, such as that of an old infirm person who does not want to die'. This rational ground is that the death is requested in the first case, and not requested in the second one. Such a ground is metadoctrinal, but even on the doctrinal view there is an important difference between the first person who suffers terribly, and the second one who does not suffer in any comparable way. If logic were that simple, a wedge argument might as well prove that the illegalization of euthanasia with respect to human beings would compel a country to illegalize all forms of killing human beings without exception, that is, inclusive of capital punishments and of the killing of members of foreign armies (to say nothing of nonhuman animals or sentient beings).

On the psychological version of the slippery slope argument against active euthanasia it is claimed that this form of killing would in fact lead to terrible consequences reflecting a general breakdown in respect for 'life' (which in the language of these human beings means human life when it suits them). There are several reasons which make this argument implausible. Firstly --as has been pointed out--, in societies in which defective babies, or even feeble old people, used to be killed, this did not lead to an easy approval of other types of killing. Secondly, in societies in which people are permitted to kill others in self-defense, people seem smart enough to also distinguish killing in self-defense from other types of killing nevertheless. And finally, it has been pointed out that in societies where euthanasia, or active euthanasia, is illegal the choice is not between a benign policy and a potentially dangerous one. The existing policy in such a society has its own evils, the worst of them being that the right of a person to decide over 'er own life and death is violated by the law of the country or state. Those who do not want the slippery slope argument to hold can always build in safeguards, and more and stronger safeguards, dependent on the time and place concerned.