What principles should govern human action? As rational beings, we should act rationally. As moral beings, we should act morally. What, in each case, are the principles involved? What is it to act rationally, or morally? It is often thought, or said, that philosophers are preeminently the people who have (and have neglected) a moral obligation to apply their rational skills to these great questions. Derek Parfit, fellow of All Souls at Oxford, is a philosopher who does exactly this. He marshals the most immediately obvious and plausible principles of rational, and of moral, action; he submits them, with great dialectical skill, to patient and thorough analysis and criticism; he tests the results against our intuitions, and draws the consequences.
He does more. One of the metaphysical questions that have engaged the attention of philosophers, at least from Descartes onward, is that of the nature of personal identity. Most of us are greatly concerned with our survival in this life as just the person that each of us is. Parfit argues that this concern with identity is misplaced; that what really does, or should, matter to us is something else, something that is indeed, in some degree, an element in such survival, but is, nevertheless, to be distinguished from the preservation of personal identity. And he argues further that once this truth is appreciated, and our ordinary beliefs revised accordingly, not only will our understanding of the principles of rational and moral action be modified, but the result will be, in certain additional ways, better for us. At least, he claims, it is better for him. But he admits that there are great obstacles in the way of our appreciating this truth.
Parfit delays consideration of this thesis until he has examined and criticized certain immediately obvious candidates for the status of acceptable general principles of rational, or of moral, action. One venerable theory about rationality is the “self-interest theory” which has been elaborated by philosophers since Hobbes. This is the view that each person should, if he is to act rationally, always act in such a way as to secure the best results for himself throughout his entire life; to secure, that is, that his life goes, as a whole, as well as possible. A rival to this view is the “present-aim theory”; according to this, it is rational for each person always to act in the way that will best achieve his current aims, as distinguished from the goals he may have in later life. Evidently either theory allows for great variation in content, depending on different conceptions of self-interest. I may believe, for example, that my self-interest is in a life of pleasure or that it is in a life in which my abilities are fully developed; my “present aims” may similarly differ.
Trivially and uninterestingly, the two theories might even coincide: e.g., if an agent’s sole present aim were to achieve the goal of the self-interest theorist. But generally, and more interestingly, they will be opposed; and in two ways. A person’s current aims may include aims, rational in themselves, that are impersonal and altruistic and the pursuit of which he knows to be against his personal interest. If my personal interest is in accumulating wealth, then giving money to the poor may run against it. Similarly the pursuit of a person’s self-regarding present aims may run counter to his long-term interest. If I seek a life of pleasurable sensations, the current pleasures of taking heroin may foreclose this long-term interest. A strict follower of the self-interest theory, on the other hand, will always regard it as rational to put his long-term personal interest first.
In the case of morality, as in that of rationality, two theories, or groups of theories, immediately present themselves as candidates for acceptable principles of action. One is the group of theories that can be characterized, in virtue of their common character, as “consequentialist”: each of us individually ought to do whatever would, so far as consequences are concerned, achieve the best overall outcome. Consequentialist theories again can vary widely in substantive content, depending on what are regarded as morally good or bad outcomes. Utilitarianism is only the simplest and most familiar of such theories, holding that the best outcome is the one that, as Parfit puts it, “gives to people the greatest net sum of benefits.” This is a standard often used by those who make public policy. What most of us, most of the time, accept, however, and, insofar as we are moral, are governed by, is not consequentialism, but some version of what Parfit calls “common sense morality,” an unsystematic assemblage of special and general obligations and prohibitions, whose validity does not necessarily depend on the consequences of observing them. We accept prohibitions of certain kinds of harmful or dishonorable actions (such as breaking promises, for example); and we accept obligations to people to whom we stand in certain special relations (children, parents, clients, colleagues, etc.), or to strangers in extreme and obvious distress.
With much subtlety and skill, by a combination of close reasoning and vivid example, Parfit exposes the flaws in unreconstructed versions of three of the four positions which have been distinguished. Individual attempts directly to follow the dictates either of self-interest or of consequentialism may be self-defeating. Parfit gives an example of a young woman who strives so hard to achieve her long-term interest of becoming a good writer that she collapses with exhaustion; as a consequence she can no longer write. Self-interest may be better served, or a morally better outcome achieved, by the development of dispositions to act in ways that, by the standards of these theories themselves, would, at least superficially, seem to count as irrational or wrong. (Parfit’s writer might have done better to cease writing for a while.) This does not by itself show these theories to be mistaken; but it does induce initial uneasiness.
More seriously, to make such individual attempts general throughout a given community may be similarly self-frustrating. It may, for example, be greatly to the disadvantage of every member of the community if each of them attempts to secure the maximum advantage for himself; and it may secure what is, from the moral point of view, a far worse outcome if each does all that either consequentialism of the special obligations of common sense morality would seem to require of him than if each does less. To cite one of Parfit’s examples, when the land is overcrowded in a peasant society, “it can be better for each if he or she has more children, worse for each if all do.” That these three types of theory—self-interest, consequentialism, and common sense morality—are, as Parfit puts it, self-defeating for groups when followed by each member may perhaps leave one of them, the self-interest theory of rationality, damaged but still standing; but it seems fatal to the two types of theory of morality. This is because a moral theory must be a theory about how we all should act, whereas a self-interest theory is simply a theory about individual rationality.
In the end, however, the outlook is less bleak for the two types of moral theory than it is for the self-interest theory. For the two former theories can be modified and refined in such a way as to come closer to each other and to meet the objections mentioned above. Thus a consequentialist can acknowledge the value of the dispositions and the force of obligations that are honored by common sense morality; and a common sense moralist can recognize the need to subordinate those special obligations to the common or general good when a certain threshold of cooperation is in prospect.
On the other hand, the self-interest theory, with its insistence on putting long-term personal self-interest first, faces, and succumbs to, a challenge from an alliance of common sense morality with the present-aim theory. Present aims, as I have already remarked, may rationally include aims congenial to the moralist, such as helping people in distress. Some may object to the present-aim theorist that he displays a bias toward the present or the near future that is irrational because the pursuit of present aims, or the fulfillment of present desires, may frustrate the fulfillment of aims or desires that we may have in the future. But the present-aim theorist and the moralist can respond that it is inconsistent, hence irrational, for the advocate of self-interest to insist on impartiality between the present and the future while also rejecting impartiality between persons.
Parfit acknowledges that the self-interest theory of rationality has, nonetheless, a continuing strong intuitive appeal. He suggests that this can be attributed in part to the long history of a false belief in a future life of rewards and punishments, for example in the prospect of heaven or hell. As long as it was believed that morality and self-interest would coincide in this all-important long-term way, the self-interest theory was a useful tool, not to be readily discarded, in the hands of those concerned with promoting morality.
Parfit’s arguments on these points extend over nearly two hundred pages of reasoning, both cogent and subtle, of which it has not been possible to give more than a selective outline. In the next long section of the book Parfit develops his avowedly unorthodox views on the nature, and on the importance, of personal identity—both being matters on which, he believes, our ordinary beliefs are mistaken. It is this section of the book that those philosophers who tend, regrettably, to ignore fundamental ethical questions are likely to find the most absorbing, and the most controversial.
It is well to be clear, first, which of our ordinary beliefs concerning personal identity Parfit would not dispute. These beliefs include the following: it is a matter of fact that the lives of most ordinary human beings exhibit both physical and psychological continuity. Their lives exhibit physical continuity in that each such person possesses one unique body and one unique brain from the beginning of his life to the end of it; and they exhibit psychological continuity in that earlier and later phases of such lives are continuously linked by overlapping memories, by the forming and execution of intentions, by the persistence or overlapping modifications of dispositions, beliefs, and desires; and these psychological continuities are made possible by the combination of external stimuli on the unique brain and body and the persistence of that unique brain and body.
It is implicit in Parfit’s position that he would accept this statement of the conditions normally satisfied in the case of an ordinary human life. It is also implicit in his position that he would declare the satisfaction of these conditions to be logically sufficient (and more than sufficient) to guarantee personal identity. In his commitment to this further step he sees himself as contradicting one generally held view: the view, namely, that so far from these being sufficient conditions of personal identity, the satisfaction of the condition of psychological continuity is, at best, a mere consequence of something else, which constitutes the real essence of personal identity and consists in the persistence of a unique separate entity, a soul-substance or Cartesian Ego. This is believed to animate the unique body and is the subject of the mental states we attribute to the man or woman.