This is the second of three posts dealing with the implications of evolutionary theory for traditional morality (see Rewriting Morality I: Goodbye to Human Dignity). In it, we'll be looking at the vexed and disconcerting issue of suicide and the closely-related topic of voluntary euthanasia.

Philosophers have debated the ins and outs of self-killing for thousands of years. The questions they ask are provocative. Are we obliged to stay alive if we really do not want to? Should people have the right to kill themselves? Should people have the right to stop others from killing themselves, if that's what they really want to do?

As a general rule, philosophers and religious thinkers have been opposed to suicide. Their reasons are many and varied. Some have argued, for instance, that God has forbidden us to take our own lives, others that it's up to God to choose the moment and the manner of our deaths, and others still that suicide is wrong because it's unnatural. But arguably the most important argument is based on the doctrine of human dignity. As I discussed in my last post, this is the idea, implicit in traditional Western systems of morality, that the lives of human beings have infinite value whereas the lives of other animals have little value or perhaps even none at all. A natural corollary of the idea that human life is infinitely valuable is that taking a human life - including one's own - is infinitely wicked. Thus, according to this argument, ending one's own life is wrong for the same reason that murder is wrong: because human life is sacred.

The argument is most often applied to suicide, but it has been applied to voluntary euthanasia as well. Kant noted that when an animal is suffering we put it out of its misery, and that's OK; but it's not OK when it comes to human beings because of the infinite worth of human life. Similarly, the Rabbi Moshe Tendler opposed voluntary euthanasia on the grounds that ‘Human life is of infinite value'. In his view, we should not cut short a person's life by even a few days because ‘a piece of infinity is also infinity, and a person who has but a few moments to live is no less of value than a person who has 60 years to live'. Thus, the injunction against assisted suicide - like that against unassisted suicide - is commonly underwritten by the doctrine of human dignity.

But the whole edifice starts to crumble once we bring Darwin into the picture. With the corrective lens of evolutionary theory, the view that human life is infinitely valuable suddenly seems like a vast and unjustified over-valuation of human life. This is because Darwin's theory undermines the traditional reasons for thinking human life might have infinite value: the image-of-God thesis and the rationality thesis (see my last post). But if human life is not supremely valuable after all, then there is no longer any reason to think that suicide or voluntary euthanasia is necessarily wrong under any or all circumstances. In fact, it starts to seem decidedly odd that we have elevated human life - i.e., pure biological continuation - so far above the quality of the life in question for the person living it. Why should life be considered valuable in and of itself, independently of the happiness of the individual living that life?

Needless to say, we must be very cautious with this argument, especially when it comes to suicide. Most people who kill themselves have not thought their decision through properly, and if they'd managed to ride out the suicidal crisis, they would have had perfectly good and happy lives. Many suicidal individuals are severely depressed, and severe depression involves an unrealistically negative apprehension of the future and the hopelessness of one's situation. Rational suicides (suicides based on an accurate picture of one's situation and future prospects) are comparatively rare. Furthermore, in assessing the rightness or wrongness of suicide, we need to take into account its effects on those left behind, as suicide usually causes immeasurable grief and suffering to the victim's family and other loved ones. Nonetheless, after Darwin, it is difficult to maintain an absolute prohibition on suicide. There may be circumstances - rare and unhappy circumstances - in which suicide is a reasonable and ethically permissible course of action. In any case, this possibility cannot be ruled out on the grounds that human life is infinitely valuable.

The argument is even stronger when it comes to voluntary euthanasia. If life is not infinitely valuable, then there is no reason to assume that the duty to preserve human life should always take precedence over other considerations, such as human happiness and the avoidance of suffering. Thus, voluntary euthanasia is no longer ruled out as an absolute evil. As with suicide, there may be circumstances in which we decide as a society that it is morally permissible. We may decide, for instance, that euthanasia is an acceptable course of action when someone with a painful terminal disease has a persisting, rational, and non-coerced desire to die - even though it involves taking an innocent human life.

Critics of euthanasia argue that it is immoral to take a person's life, even when that person is suffering and wishes to die with dignity. After Darwin, we might be more inclined to think that it is immoral to force people to keep on living when they would rather not. Here's something to think about. In many ways, we treat other animals abysmally. But if a horse or a dog or a cat is suffering terribly from a fatal injury or disease, or if it has limited prospects for quality of life in the future, most people agree that the humane thing to do is to put it out of its misery. Not to do so would be considered inhumane. However, because of the inflated value traditionally assigned to human life, we are less humane in our treatment of human beings who are suffering or have a painful terminal illness. This is an ironic exception to the general rule that the doctrine of human dignity secures better treatment for humans than for nonhumans. In this one instance, we treat nonhuman animals more humanely than we do human beings, because of superstitious beliefs about the value of human life. People are made to suffer needlessly because of superstition. If it is acceptable to put nonhumans out of their misery, why is it not acceptable to do the same for people who request it, or in some cases beg for it? One might even argue that euthanasia is less morally problematic in the human case, because people can give their explicit and reasoned consent, whereas other animals cannot.

An evolutionary perspective doesn't completely solve the problem of suicide or euthanasia. Many questions remain. In what circumstances should we forcibly prevent people from killing themselves? Should physician-assisted suicide be available to people who are simply tired of life? Evolutionary theory cannot answer questions like these. What it can do, though, is deactivate some of the traditional arguments against suicide and euthanasia, removing them from the table and thereby opening up the possibility that, at least in some situations, they might be acceptable courses of action. If nothing else, evolutionary theory wakes us up to the fact that we can no longer take a ready-made answer to these difficult questions from a holy book or religious authority. We're going to have to think it through.

Of course, an evolutionary perspective does not imply that we should take suicide or euthanasia lightly. On the contrary, a strong argument can be made for the opposite position. The evolutionary process that gave us life involved the suffering of untold millions of people and other animals. Does this not oblige us to cherish our existence if we possibly can, to make the most of the life that our forebears unwittingly bequeathed us with their torments and agonies?

In my next post, I'll consider how evolutionary theory impacts the issue of animal rights and the proper treatment of nonhuman animals.

-This post is excerpted, with changes, from the book Darwin, God and the Meaning of Life by Steve Stewart-Williams - available now from,, and

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