Criticisms of the theory - Coherence
So far as coherence is concerned it is not clear what the theory is actually claiming. What for instance is the meaning of "the greatest happiness of the greatest number?" What is meant by happiness? How can happiness (and suffering) be measured? Is it total happiness, average happiness, or something else that is to be maximised? Finally, happiness of what? What is happiness?-The Benthamite equation of happiness with (mere) pleasure was rejected early on by Mill, for whom the happiness to be maximised was eudaimonia or human flourishing. (As Mill put it, "Better to be a human being dissatisfied than a pig satisfied.") Contemporary utilitarians, accepting people's variability, their powerful desire for autonomy, and their different perceptions of what it is to flourish, tend to aim to maximise satisfaction of individuals' autonomous preferences as being the best way of maximising overall happiness.4 Measuring happiness (and suffering) is clearly a major problem for utilitarianism, but modern utilitarians tend to agree with their spiritual accomplices, modern economists, in accepting that people can roughly measure at least their personal assessments of happiness and suffering5 analagously to the way they can measure benefits and disbenefits in monetary terms (by buying goods or insurance policies and in their betting behaviour).
Maximising happiness-As for whether it is total happiness, average happiness, or something else that is to be maximised, a common response is to accept the widespread human concern with fairness as a fact about human nature and therefore aim at net average preference satisfaction as the appropriate goal. Its achieve- ment can be expected as a matter of fact to maximise total happiness.6 Scope-The problems concerning to what or whom the moral theory applies are not unique to utilitarianism; deontological ethical theories may be just as troubled about how to incorporate non- human animals, very young human beings, and permanently unconscious human beings within their theoretical framework. Modern utilitarians tend to accept the (extraordinarily radical)Benthamite claim that anything that can suffer falls within the scope of morality but they may accommodate the intuition that people are morally more important by differentiating according to the differing "interests" of people and lower animals. As for the somewhat abstruse debate about whether the scope of utilitarianism should include only existing sentient beings, existing and future sentient beings, or all possible sentient beings, suffice it here to assert that the problem is no greater for utilitarianism than it is for other types of ethical theory and that the most plausible option seems to me to be the second alternative. The first would exclude the moral interests of people who will exist but have not yet come into existence and the third would require moral consideration to be given to an infinite number of people and animals that will never exist. (This support of the second option in no way excludes from being morally relevant counterfactual consideration of possible people who might be affected by a contemplated action.)