It is interesting, in this context, to think again of our earlier argument that membership of the species Homo sapiens does not entitle a being to better treatment than a being at a similar mental level who is a member of a different species. We could also have said – except that it seemed too obvious to need saying – that membership of the species Homo sapiens is not a reason for giving a being worse treatment than a member of a different species. Yet in respect of euthanasia, this needs to be said. If your dog is ill and in pain with no chance of recovery, the humane thing to do is take her to the vet, who will end her suffering swiftly with a lethal injection. To ‘allow nature to take its course’, withholding treatment while your dog dies slowly and in distress over days, weeks or months, would obviously be wrong. It is only our misplaced respect for the doctrine of the sanctity of human life that prevents us from seeing that what it is obviously wrong to do to a dog, it is equally wrong to do to a human being who has never been able to express a view about such matters.
Peter Singer, Practical Ethics
ethics, euthanasia, utilitarianism