Last night’s documentary (featuring Terry Pratchett) graphically illustrated the plight of some desperate people whose serious and unremitting illness consigns them to a drastically diminished and suffering-filled future, and who want help to end the lives that they now find unbearable. Currently unable to be legally assisted to die in the UK in the way that they would like, the only hope for some is to go to Dignitas in Zurich to end their lives in a strange and sterile place (although, it has to be said, Dignitas appear to do their best on this front), and earlier than they might otherwise choose, as they know that they must go while they are still able to travel. This is not how things ought to be; and a rational, informed, and compassionate society would arrange things differently.
We know that many people who are terminally ill would choose to stay alive as long as they can, and perhaps choose to enter a hospice when they are close to the end. As autonomous rational people, they should be free to make these choices, and we ought to help them where appropriate. However, compassion dictates that we ought to help those other autonomous rational people who are terminally or unbearably and incurably ill, and for good reasons don't want to enter a hospice or have palliative care but would instead freely choose to end their lives (because they feel that they no longer have any kind of quality of life left, and know that things will only get worse), but lack any reliable and humane means to bring this about themselves. And we shouldn't forget that we might find ourselves in that position one day, and might then wish to be shown such compassion ourselves, and so it is rational for us to agree to have the option available so long as it can be safely legislated for - which it can.
In light of this, assisted dying (where the person is assisted to self-administer the agent that will cause death) ought to be legal in cases where an expert assessment panel is happy that these three criteria are met:
1) The person is certified by two independent doctors to be either terminally ill, or to have a serious and incurable illness that will cause them unbearable suffering with no hope of recovery.
2) The person is certified to be of sound mind.
3) It can be shown beyond all reasonable doubt that the person is properly informed on the matter, has an enduring desire to end their life, and is not being coerced into this by others.
Surely it is not beyond human ingenuity to create such panels (probably as part of the NHS) consisting of medical, legal, and ethical experts, operating under proper oversight, to meet and consider each application for assisted dying on a case by case basis, to carefully weigh up all of the actual relevant evidence on the matter, and to reach sound decisions on such cases based upon the criteria above? And the likely existence of ambiguous cases (on which we probably ought always to err on the side of caution) does not demonstrate that there will not be many more clear-cut cases on which the panel could arbitrate (any more than the fact that it would be difficult to say whether some particular men would be classified as bald or not entails that there are no clear cases of men who either are or are not bald).
And, to dispose of an oft-cited red herring, the person assisting the death need not necessarily be a doctor, and hence this need not conflict with the Hippocratic Oath. We might decide that it could instead be assisted by someone specially trained and certified to carry out this task - as A.C. Grayling suggests, a new medical speciality of thanatology.
As to the slippery slope arguments that say that if we legalize assisted dying we will inexorably slide down a slope to a point at which the sick and vulnerable will get coerced into agreeing to die, or will sometimes just be murdered, they are unsound in principle unless the appropriate causal connections can be demonstrated to exist such that accepting some (reasonable) proposition (e.g. that we ought to legalize assisted dying under certain strict conditions) logically entails a slide into accepting some (unreasonable) proposition (e.g. that some vulnerable people should be killed against their will). Moreover, there is no good reason to suppose that we cannot just dig our heels in and say ‘this far and no further’, by framing sound laws accordingly, to prevent us from sliding down the slope.
It might be then argued that, whilst a slippery slope is not logically inevitable in principle, nevertheless the world is such that the slope will be slippery in practice. However, when we look at the actual facts from places where assisted dying or euthanasia have been legalized (such as Oregon, Belgium, and the Netherlands), the consensus of expert opinion (when formed by a reliable method) is that there is just no good evidence for the sorts of abuses of the vulnerable that the existence of a slippery slope would entail; and nor is there any good evidence for an increase in non-voluntary euthanasia (in fact, there has generally been a decrease), or of an increase in assisted dying beyond what would be expected due to greater public awareness and improved reporting by GPs. So, the existence of such a hypothetical slope is effectively refuted in this case both in practice and in principle (see, for example, here, here, and here; and for additional supporting statistics that the vulnerable are not at risk under such laws, this, and this).
Moreover, after the Dutch passed the law in 2002 legalizing assisted dying and euthanasia, several different governments have held power there, but there has been no serious suggestion in government that the law is leading to abuses. Furthermore, Belgium and Luxembourg have since enacted their own similar laws, after studying the effects of the law in Holland - which would be highly unlikely if there was good evidence of abuses taking place there. The situation is similar in the US states of Oregon and Washington. In fact, By contrast to the purely hypothetical slippery slope, the existence of people who are terminally or unbearably and unremittingly ill, and would freely choose to be helped to end their lives, is not hypothetical at all.
Whilst killing is normally and rightly considered to be a great harm (as it thwarts an autonomous rational agent's desire to go on living, terminates all of their future plans and chances for happiness, might cause them suffering and fear, and might cause distress and fear in others), there are cases in which the greater harm is to compel people to continue to live with unbearable suffering, and to withhold the help that could be given to such ill people to release them from a prolonged, hopeless, and miserable life. What if an autonomous rational agent desires not to continue living, but to die instead? And what if the suffering entailed by continuing to live greatly outweighs any suffering that would be caused by being killed? And what if, rather than causing the agent and others fear, the possibility of death brings comfort as they know that they have a relatively painless and humane way out if life is unbearable due to incurable or terminal illness? Surely, under such conditions, the reasons for the death of that person to be considered a great moral harm are no longer present, and the moral situation is actually reversed. We should remember that a life only has value to the person living it to the extent that they want to continue living, and are able to do so relatively free from pain and suffering.
If you doubt the above, then imagine (as a thought experiment) that you happen upon a car that has been in a terrible accident, and the occupant is screaming as they burn alive. Now imagine that you know beyond any reasonable doubt that the occupant cannot get out of the car (either on their own or with anyone else's help), but that you have to hand the means to kill them reliably, quickly, and painlessly (a gun, say), and that you would not be prosecuted for doing this. And imagine further that the occupant knows this and is pleading for you to put them out of their misery. So, squeamishness aside, ought you to kill them swiftly as an act of mercy so that they suffer no more; or ought you to do nothing, ignore their pleas for mercy, and let them suffer terribly and then eventually die anyway?
If you think the former then you must agree that there can be greater harms for a person than death alone (and the act of killing that would cause that death), and that merely living for a bit longer isn't always valuable for the person whose life it is, or would be desired by them. And if your objection to assisted dying was based upon the inviolable sanctity and intrinsic value of life (no matter how little value that life holds for the person living it), then to be logically consistent you ought now to change your mind about this objection. Alternatively, if you would let the person burn to death, for the same reason that you object to assisted dying, then you are at least being logically consistent in your reasoning. However, I would argue that in this case it might be that some false beliefs that you have about the world are misleading you into acting immorally (see the next section for more on this). Or, if not this, then you ought to consider whether you would want to be put out of your misery if you were the person burning to death in the car, and, if so, reflect upon exactly how you could then morally justify treating someone else in a way that you would not want to be treated yourself in similar circumstances.
And those who would declare, on religious grounds, that life is not ours to take under any circumstances (including, perhaps, our own life), or who would offer some theological justification for people's continued suffering, are first required to prove to us the existence of their god; to then prove that their god has decreed this to be so; and to then demonstrate why we all ought to obey such commands anyway, rather than just rejecting them on justifiable moral grounds when it would be too cruel to do otherwise. Good luck with that, but in the meantime we need give no greater weight to such beliefs than to any others based upon such unreliable and non truth-seeking methods as mere speculation, hearsay, desire, wishful thinking, tradition, delusion, and other ungrounded assertion (i.e. what some religious people collectively call 'faith', and consider to be a virtue); and to not allow such people to claim an unwarranted monopoly and authority on moral truth, or to have a disproportionate and unwarranted influence in the making or changing of relevant law on the matter (or on any other matter, come to that). As the number of false beliefs vastly outnumbers the number of true ones, and as false beliefs can be and have been transmitted just as easily as true ones, an unreliable, non truth-seeking method such as the method of faith is almost certain to select false beliefs. As such, the method of faith doesn't produce actual knowledge at all, only unwarranted belief (as opposed to a reliable method, such as the method of science). And it is exactly as we should expect that such a method has produced endless confusion and disagreement amongst believers, with the predictions made by its propositions routinely failing to transpire, and a myriad of inconsistent and mutually contradictory beliefs. Of course, to select any one subset of these beliefs as being true, whilst rejecting others, would be purely arbitrary and just special pleading. It's far worse than that for people who base their beliefs on such methods though, as we actually have very good reasons to suppose their beliefs to be not just unproven and highly improbable, but manifestly false.
Of course, some people who believe primarily on religious grounds that assisted dying should not be legalized do not actually choose to argue on these grounds, but instead use one of the secular arguments (often the 'slippery slope') as a fig leaf for their true reasons. Such people are at best disingenuous, and lose credibility as a source of reliable knowledge on the matter. If they really think that the religious reasons for their beliefs are warranted, then, if they are genuine truth-seekers, they ought to submit these reasons in the court of informed public debate. And, if not, then to base such strong belief upon unwarranted reasons would be irrational. Furthermore, if any such people start with a strong prior commitment to some conclusion or other (e.g. that assisted dying is morally wrong, based upon the religious sanctity of life), and do nothing but try to fit evidential data (rejecting or just ignoring any data that doesn't fit) to different hypotheses that would also tend to entail the same sort of action (e.g. that a slippery slope is inevitable), then they are not honestly, objectively, and reliably seeking the truth, but are instead performing some sham version of scientific or philosophical enquiry in order merely to persuade others and perhaps achieve some agenda or other (similar in that regard to the sophistry of intelligent design, where rejection of the theory of evolution on religious grounds is hidden behind specious scientific arguments). It is just not a virtuous way to try to acquire actual knowledge. Whilst such particular arguments as the slippery slope ought to be assessed on their own merits (as we are genuine truth-seekers), we have good reasons to doubt the credibility of people who would argue in the way that I have described as sources of reliable knowledge, and we ought therefore to be highly suspicious of any claims that they make. For a pertinent example of a religious person (the Archbishop of Canterbury, Rowan Williams) being challenged when arguing this way, see this eloquent and well-argued letter from someone who has personal experience of assisted dying (and a further reply to the Archbishop's response, here).
Those who would disagree with me about assisted dying legislation are, I believe, mistaken about certain facts (e.g. that God exists and has decreed human life to be sacred, that properly formulated and operated assisted dying and euthanasia legislation has led to proven cases of abuse elsewhere, or that palliative care can ameliorate all unbearable suffering and indignity in the dying); are employing fallacious or otherwise faulty reasoning (e.g. that all slopes are slippery ones, or that death is always the greatest harm for a person); or are otherwise acting irrationally. Autonomous and rational agents should be legally and morally free to choose to end their lives, and, under strict legal guidelines and criteria, there ought to be assistance available to help them. If we were rational, logical, and cognizant of all of the relevant facts, then we would legislate to allow such acts of compassion to end unnecessary and unwanted suffering, and would want to be shown such compassion ourselves if we were in those dire circumstances.