In view of what has been said in Part One of this book it is obvious that my intention here, in Part Two, is not to pose as a moral expert, who will reveal the answer to the question ‘What is morally acceptable behaviour?’ as the medical expert might give one the answer to the question ‘What sort of factors are conducive to heart failure?’. Nor is it my intention to ‘prove’ that a particular moral viewpoint is incumbent upon us, if we assume ‘prove’ to mean ‘demonstrate in some incontrovertible manner’. My purpose rather is to put forward an argument for a particular point of view and to appeal to the reader to consider the argument as an argument. Naturally it is my view that the argument is convincing and that it consequently leads us to accept a particular moral viewpoint. But at the same time I am aware, and it is important that the reader should be too, that this argument, which is not in essence original, and this viewpoint, which has been held by various people throughout history, has never yet met with universal acceptance. Some people evidently do not find the argument convincing. All that is asked of the reader is that he should examine it for himself and accept or reject it by reference to the argument rather than by reference to such considerations as whether he happens to like it, whether it leads to conclusions that he has been brought up to accept, or whether it coincides with what most people think.