Euthanasia has a tendency to slide from the voluntary to the compulsory, as people increasingly make judgments on behalf of others as to what is a human life worth living. The opinion is widespread that the persistent vegetative state — the condition in which a person with some kind of brain injury remains alive but unresponsive to stimuli — is one such life not worth living.
The problem is a complex one. A recent paper in The Lancet, from researchers in Cambridge, England, and Liege, Belgium, describes a method by which they proved that, of 16 patients in a persistent vegetative state, 3 demonstrated, by means of electro-encepahalograph (brainwave) recordings, that they were able to follow instructions, in this case to imagine either their hand or big toe making a movement.
Perhaps even more alarming, the EEG recordings of three of the sixteen normal control subjects, who were given the same task to perform and who were undoubtedly fully conscious (though students of psychology), did not reliably show that they had been able to follow instructions
In other words, while a positive test shows that there is a fair degree of consciousness, a negative test does not show an absence of such a degree of consciousness. The possibility remains that an unknown but large proportion of people in a persistent vegetative state retain a higher level of consciousness than hitherto believed, certainly by those inclined to call them “vegetables” as a prelude to withdrawing all treatment. As I used to tell my medical students, we must always remember that just because a patient cannot speak it does not mean that he cannot hear (and understand). There is a tendency to talk in the presence of the unresponsive as though they were there.
Of course, it is also true that being able reliably to imagine moving a hand or toe in response to a command to do so does not constitute a worthwhile life. It might very well be that consciousness makes the persistent vegetative state far worse than it would have been if accompanied by complete unconsciousness. Surely, no one would wish the condition of consciousness while in a persistent vegetative state upon himself if he had an alternative.
However, this is not quite the same thing as saying that such a life is not worth living. Whether a life is worth living can be judged only by the person living it. Most young people, if asked, say that life would not be worth living for them in a state of tetraplegia (paralysis from the neck down); most tetraplegics, though, do not agree, and do not want to die, much less ask for voluntary euthanasia by fatal injection or withdrawal of treatment.
Where does this leave medical ethics? Health economists would have no doubts: the money spent to keep a person in a persistent vegetative state alive could be better spent in some other way; that is to say, it would result in more health benefit per dollar expended. This, of course, depends upon there being a comparative measure of health benefit that is reliable and uniform across all situations and circumstances, like the utilitarians’ supposed unit of pleasure, which is very doubtful.
We are always, then, acting to some extent in the dark, not only because we are imperfectly informed and there are things that we do not know (such as the thoughts and feelings, if any, of patients in a persistent vegetative state), but because not all things are commensurable even if known. As Hippocrates put it quite a long time ago, judgment is difficult.