Appeals to the public interest in fields such as politics and law are commonplace. Government policies are criticized for contravening the public interest. A whistleblower’s violation of government secrecy laws may be deemed justified because their disclosures are in the public interest. Human rights violations may be considered justified if a particularly weighty public interest (national security, public health) is at stake. If biobanking promotes the public interest, its ambiguous relation to privacy may be deemed acceptable. The problem is that such appeals are made without clarifying what the public interest is and how it can be determined.
Political philosophers are particularly well qualified to provide much-needed conceptual clarification and moral argument, yet during the past few decades they have largely ignored the issue. This is the consequence of a certain uneasiness with the concept of the public interest: It has been criticized for being empty, inimical to contemporary pluralistic societies, and a mere veil for the self-serving interests of the powerful. Proponents of the concept, however, respond that it is possible to provide a clear account of the public interest that meets (most of) these criticisms. The aggregative theory, for example, holds that the public interest corresponds simply to the sum of the private interests of those who make up the public. The procedural approach, instead, hopes to distill the public interest from a plethora of private interests through the process of either democratic competition or deliberation. Where these two accounts of the public interest derive the public interest from people’s private interests, the unitary account derives it instead from a comprehensive moral theory that applies equally to private and public interests. Finally, the civic account maintains that the public interest consists in interests we share in our capacity as citizens.
Proponents of the concept of the public interest, moreover, argue that it can do normative work no other concept can. Though political philosophy has been dominated by the concept of justice for decades, not all political philosophical matters are reducible to questions of justice. Public interest is used to justify facilities, policies, and actions that are somehow beyond the purview of justice, such as public infrastructure, the disclosure of state secrets, the placing of limits on human rights, and much more.