The idealists among us want to respond by postulating that participants seek “public good,” that persons try, as best they can, to take the interests of all members of the community into account when they make in-politics decisions. The extent to which individuals are motivated in this way remains, of course, an empirical question. The point to be emphasized, however, is that any degree of “other-regardingness” can be incorporated, without difficulty, into the basic contractarian paradigm. The contractarian, or complex exchange, model of politics depends not at all on the postulated motivation of the individual actors.
The contractarian model does depend, however, on the presumption that the “public good” or “private good,” or whatever mixture of these might be relevant, is internally conceived and hence is subjective to the person who acts. A person may, for example, behave strictly in accordance with the idealist’s norm; he may try to take into account the interests of all others in the community. But such interests enter as arguments in the choice calculus internally to the participant; the interests of others are imputed to them as estimated by the participant. These interests cannot reflect expressions of others in any direct manner.
Brennan and Buchanan, The Reason of Rules, p. 42.
People tend to think altruistic preferences are entirely desirable. I think, however, that many of the meddlesome preferences which reduce liberty are based on misguided altruism. Paternalist health promotion policies seem to derive from concern for the welfare of individuals, combined with a conviction that the paternalist knows their interests better than they themselves.