Can a utilitarian calculus ever be devised? the question of why pleasure or pain is good or bad is irrelevant. People prefer pleasure to pain. Pleasure is, in a sense, the escape from pain, the stopping of pain. Sadomasochism... That is not pain but pleasure. The idea of utilitarianism is to say that, given a set of circumstances, what is the sumum bonum, the greatest good, is happiness and therefore the solution to any dilemma in which the question of morality is in play (the question of what is right or wrong) will involve the realization of what solution will include the greatest amount of happiness either for the individual himself regarding his or her own acts, or for the system itself, which includes all thinking, judging people. The most moral solution to an ethical dilemma is what involves the most amount of happiness.
This is the utilitarian rule of thumb, and though this rule of thumb is not a categorical imperative, it often works.
My own personal problem with utilitarianism involves the use of drugs. A morphine high is by no means a low pleasure. Firstly, it involves complex chemistry and pharmacological knowledge in order to exist. Secondly, the feeling of morphine is probably one of the best feelings a person can have. So, the question of morality for a heroin addict involves, "Is it moral for me to rob this person to get money to experience the best feeling of pleasure?"
But, the experienced utilitarian can break this down. A morphine high does not include true happiness. Pleasure is not the utilitarian calculus, happiness is. Happiness and pleasure are often used interchangeably in utilitarianism. Perhaps this is the root of some problems; the snares of language. In any case though, the immediate consequence of a heroin addict making the decision to rob someone does not in any way relate to his eventual feeling of heroin, even though he is robbing for the money for the heroin, and so his judgment would not even constitute a utilitarian calculus.
Act utilitarianism does not work for the species, only a rule utilitarianism does...