Common-sense Egoism: According to this view, egoism is a vice. It involves putting one’s own concerns over those of others. One’s behavior is egoistic if it involves putting one’s own interests over those of others to an immoderate degree.
Argument For: Human agents always, at least on a deep-down level, are all egoists insofar as our behavior, explainable in terms of our beliefs and desires, is always aimed at what we believe is our greatest good (Baier, 1991, p. 203).
Objection: The psychological egoist confuses egoistic desires with motivation. An agent may act contrary to his desires and what is in his own best interest. People often act in ways that they know are detrimental to their well being. Moreover, what one most wants may not be in their own self-interest (e.g., giving money to Amnesty International rather than buying a new CD). MacKinnon adds that, "Even if it were shown that we often act for the sake of our own interest, this is not enough to prove that psychological egoism is true. According to this theory, we must show that people always act to promote their own interests" (p. 23). If we can find only one counterexample to psychological egoism, then it is not true.
Egoism as a Means to the Common Good
Argument For: According to the economist, Adam Smith, when entrepreneurs are unimpeded by legal or self-imposed moral constraint to protect the good of others, they are able to promote their own good and, as a result, provide the most efficient means of promoting the good of others (Baier, 1991, p. 201; see MacKinnon, p. 24). Such a view leads to the doctrine that, "if each pursues her own interest as she conceives of it, then the interest of everyone is promoted" (Baier, 1991, p. 200).
Objection: Apart from positing an "invisible hand" guiding the market processes, the common-good egoist makes the fallacy, ascribed to J.S. Mill, that if each person promotes her own interest, then everyone else’s interests are thereby promoted. "Clearly, this is a fallacy, for the interests of different individuals or classes may, and under certain conditions (of which the scarcity of necessities is the most obvious), do conflict. Then the interest of one is the detriment of the other" (Baier, 1991, p. 200).
Rational Egoism: Rational egoism is concerned with reasonable action.
Strong Rational Egoism: It is always rational to aim at one’s own greatest good, and never rational not to do so (Baier, 1991, p. 201).
Weak Rational Egoism: It is always rational to aim at one’s own greatest good, but not necessarily never rational not to do so (Baier, 1991, p. 201).
Argument For: When doing something does not prima facie appear to be in our interest, our doing said act requires that we justify our action by showing that it is in our interest, thereby justifying our action.
Objection: Such an approach to justifying actions in our own interest may be abused if we do not have criteria established to determine what the interests of agents amount to. If such criteria are established, such actions may be reasonable so long as they do not result in conflicts between agents. In such cases, creative middle ways are called for.
Ethical Egoism: Coupled with ethical rationalism—"the doctrine that if a moral requirement or recommendation is to be sound or acceptable, complying with it must be in accordance with reason"—rational egoism implies ethical egoism (Baier, 1991, p. 201).
Strong Ethical Egoism: It is always right to aim at one’s own greatest good, and never right not to do so (Baier, 1991, p. 201).
Weak Ethical Egoism: It is always right to aim at one’s own greatest good, but not necessarily never right not to do so (Baier, 1991, p. 201).
Argument For: If we accept rational egoism, and if we accept ethical rationalism, then we must accept ethical egoism. This is the case because if acting in one’s own self-interest is reasonable, then it is a moral requirement that one acts in one’s own self-interest.
Objection: Ethical egoism is incompatible with ethical conflict-regulation. Consider the following example from Kurt Baier, regarding the problem over whether it would be morally wrong for me to kill my grandfather so that he will be unable to change his will and disinherit me (1991, p. 202):
Assuming that my killing him will be in my best interest but detrimental to my grandfather, while refraining from killing him will be to my detriment but in my grandfather’s interest, then if ethical conflict-regulation is sound, there can be a sound moral guideline regulating this conflict (presumably by forbidding this killing). But then ethical egoism cannot be sound, for it precludes the interpersonally authoritative regulation of interpersonal conflicts of interest, since such a regulation implies that conduct contrary to one’s interest is sometimes morally required of one, and conduct in one’s best interest is sometimes morally forbidden to one. Thus, ethical egoism is incompatible with ethical conflict-regulation.
References: Baier, Kurt. 1991 "Egoism" in a Companion to Ethics. (ed. P. Singer) Oxford: Blackwell, 197-204.