Preference utilitarianism is one of the most popular forms of utilitarianism in contemporary philosophy. Unlike classical utilitarianism, which defines right actions as those that maximize pleasure and minimize pain, preference utilitarianism promotes actions that fulfil the interests (preferences) of those beings involved.[citation needed] The beings may be rational, that is to say, their interests may be carefully selected based on future projections, but this is not compulsory; here, the definition of "party" extends to all sentient beings, even those living solely in the present. Since what is good and right depends solely on individual preferences, there can be nothing that is in itself good or bad: for preference utilitarian’s, the source of both morality and ethics in general is subjective preference.[1] Preference utilitarianism therefore can be distinguished by its acknowledgement that every person's experience of satisfaction is unique.
The theory, as outlined by R. M. Hare in 1981, is controversial, insofar as it presupposes some basis by which a conflict between A's preferences and B's preferences can be resolved (for example, by weighting them mathematically). In a similar vein, Peter Singer, a major proponent of preference utilitarianism and himself influenced by the views of Hare, has been criticised for giving priority to the views of beings capable of holding preferences (being able to actively contemplate the future and its interaction with the present) over those solely concerned with their immediate situation, a group that includes many animals and young children. Hence, in cases of abortion, the views of the parent (however selfish or not, as the case may be) are prioritised over those of the foetus, without recourse to any (perceived) rights (here, the "right to life"). There are, he writes in regard to killing in general, times when "the preference of the victim could sometimes be outweighed by the preferences of others". Singer does, however, still place a high value on the life of rational beings, since killing them does not infringe upon just one of their preferences, but "a wide range of the most central and significant preferences a being can have".