D. Vinson Is Mill A Rule Utilitarian? I don't believe so. I must begin my argument with two definitions and one assumption. First, Rule Utilitarianism states that right action is defined by whether or not a given action is an instance of a moral rule that tends to maximize utility. Second, Act Utilitarianism states that right action is defined by whether or not a given action maximizes utility. Finally, the Utilitarian Principle holds that right actions are right in proportion as they tend to promote happiness; wrong as they tend to produce the reverse of happiness.
I hope that my assumption will be granted as it is taken verbatim from the text. With these notions as a starting point I believe that I can now show Mill to be an act-utilitarian. The case for Mill being a rule-utilitarian is a strong one. Mill certainly relies heavily on rules in his treatise and argues that they are useful to the point of necessity. To consider the rules of morality as improvable is one thing; to pass over the intermediate generalizations entirely, and to endeavor to test each individual action directly by the first principle is another. Further on in the text, Mill even seems to minimize the importance of the first principle by declaring that it is only useful for settling disputes over secondary principles... only in these cases of conflict between secondary principles is it requisite that first principles should be appealed to.
The problems with Mill being a rule-utilitarian begin to arise when we examine its method. When, in the statement of the Utilitarian Principle, Mill says that right actions tend to promote happiness, some have taken that to mean that Mill must only be dealing with classes of action. If this were the case, then an instance of a right action class, if in the wrong (of any infinitely complex) set of circumstances, may fail to maximize happiness but still be right. Furthermore, an act-utilitarian may still make great use of moral rules to help make right actions. It may be that moral rules provide a generally reliable guideline for how to act without determining that it is always the right way to act and that they indicate completely wrong action in some cases. This is supported by a passage from the text.
Mankind must by this time have acquired positive beliefs as to the effects of some actions on their happiness; and the beliefs which have thus come down are the rules of morality for the multitude, and for the philosopher until he has succeeded in finding better. That philosophers might easily do this, even now, on many subjects; that the received code of ethics is by no means of divine right; and that mankind have still much to learn as to the effects of actions on general happiness, I admit or rather earnestly maintain. If our secondary principles are prone to revision and even deletion then either Mill is an act-utilitarian who allows use of rules that tend to maximize utility to guide our action on simple, or at least morally commonplace, decisions but holds the ultimate test of moral rightness to be the application of the Utilitarian Principle to actions; or he is a rule-utilitarian that says the criteria for determining rightness of action may be wrong, revised, or discarded. We are here still left with the nagging inclusion of the word tend in the Utilitarian Principle. In wanting to do what is right, but conforming to the idea of maximizing happiness, utilitarians are required to guess at the consequences of their actions. The only inductive way to do this is look at similar actions applied to similar circumstances and attempt to determine the causation.
This allows us to develop general guidelines for behavior, in part, based on consequences that we predict will likely occur from applying a certain action to a certain set of circumstances. It is an unfortunate fact, however, that humans cannot surely predict future consequences and many times get it wrong when they attempt to. It is for this reason that these secondary principles must be relegated to influencing decisions where a mere tendency to maximize utility in cases where the circumstances are quite well understood is acceptable. It must be understood, however, that these secondary principles are not only predicated on past applications of act-utilitarianism (at least the first time someone found that the act maximizes utility) but that they also must appeal to the first principle when they are in conflict, are not wholly applicable, or the decision simply requires a more thorough understanding of possible consequences. In these cases the first principle is used to determine what an action will tend to do. In conclusion, I don't believe that an equivocal answer on Mill as rule- or act-utilitarian can be got solely from Utilitarianism.
This is due mostly to the difficulty in attempting to make an original philosophy conform to one or another category that wasn't invented until after its formation and to the author having no clear intention to conform his philosophy to one or the other idea. I do believe that Mill leaned more toward act-utilitarianism due to his understanding of the fluidity of rules in varying circumstances and his desire to find a rigid principle that may be consulted to determine any right or any wrong..