Definition: Consequentialism - Any moral theory which holds that the consequences of an action determine the moral status of the act.
Thus, anyone who believes that we must take the consequences of an action into consideration to determine if the action is right or wrong, is a consequentialist. The ends justify the means, to put it in a more pithy formulation. If good consequences follow from an action, then the act is right; if bad consequences follow from an action, it is wrong. The problem for the consequentialist is that the terms 'good' and 'bad' are ambiguous. So the definition of goodness one offers gives rise to the different types of consequentialist moral theories.
Consequentialists have traditionally offered three different definitions of 'good' which gives us three distinct moral theories.
All versions of Ethical Egoism (see the distinction between ethical and non-ethical Egoism below) have this feature in common: they all suppose that moral designators are relative to the interest of the moral agent. Thus, if I say that "X is good" I mean that X is good relative to my interests. But what is my best interest? Is my best interest whatever I think at any given time is my best interest? That is, is my interest determined by what I want at any given time, or can I be mistaken about my own best interest? Whatever my best interest is is a factual matter. But how do we flesh out what our interests are?
Once we've determined what our interests are, and once we establish that all (or perhaps most) people act so as to further their own interests, we must see how this affects value systems. How are we to make moral designations relative to our interests? Should it be the case that every 'moral' act be determined relative to me? or should I universalize this principle to others? Another important question to ask is "Is Egoism necessarily selfish?" Is it possible to create an Egoistic theory which has some notion of the common good?
It's important to note the difference between Psychological and Ethical Egoism. Notice that the first theory is not telling us what we ought to do, rather it is offering a description of what we actually do (whether or not it is correct is a distinct questions). As such it is not a normative theory, but a descriptive one. We are not interested in this type of Egoism. We are more interested in the philosophical, or normative, thesis we find in latter type of Egoism.
However, we still have an ambiguity in our theory since we have not clearly defined who we are talking to. Thus, there are two different expressions of Ethical Egoism:
Again we should note the importance distinction between these two different forms of Egoism. If we apply our five criteria of an acceptable moral principle discussed earlier, we can clearly see that Individual Ethical Egoism fails the universalizability criteria. Hence, if we want to adopt Ethical Egoism, it appears we must also desire everyone else to act in the same way. Some philosophers think this leads to a paradox, and that this paradox is the primary reason we should not embrace this Ethical Theory. Others argue that there is no real paradox, and even if there is, it is not a sufficient objection to undermine Egoism as an acceptable normative theory. We will see that Thomas Hobbes gives us an argument in favor of Egoism.
There is a second type of Consequentialist theory, closely related to Egoism called Hedonism. Hedonists claim that 'good' should be defined, not in terms of happiness, but in terms of pleasure!
On close inspection, however, it is not entirely clear if there is a significant distinction between Egoism and Hedonism since Egoists (along with Utilitarians) tend to define 'happiness' in terms of pleasure and pain. Some will argue that these two theories are really indistinguishable.
The final type of consequentialist moral theory is Utilitarianism.
The significant difference between this theory and Egoism/Hedonism is the focus of the action. For the Utilitarian the needs of the greater number tends to ought weigh the needs of the minority. One clear expression of this type of moral theory is the military which says that individual soldiers (or even the military as a whole) are expendable for the good of the greater community. For fans of the original "Star Trek," this is the moral theory of Mr. Spock.
We'll explore both Egoism and Utilitarianism in the essays of Thomas Hobbes and John Stuart Mill, respectively.