‘Everybody to count for one, nobody for more than one’: The principle of equal consideration of interests from Bentham to Pigou

摘要

SUMMARY In chapter 5 of Utilitarianism, John Stuart Mill argued that the principle of utility ‘is a mere form of words without rational signification, unless one person’s happiness, supposed equal in degree [...], is counted for exactly as much as another’s. Those conditions being supplied, Bentham’s dictum, “everybody to count for one, nobody for more than one’” might be written under the principle of utility as an explanatory commentary’. The principle implied in this statement, often emancipated from its hedonistic attributes, is the principle of impartiality, or ‘the principle of equal consideration of interests’. This paper explores the meaning and implications of this principle by studying its changing definitions from Bentham to Pigou. Such a delimitation reveals two features of the present analysis: first, it examines a question that was at the crossroads between moral philosophy and economics; and second, it considers a period in which utilitarian ethics and marginalist economics were strictly based on hedonistic and cardinalistic assumptions. In this context, the question of how to weigh the happiness of different individuals was crucial for any application of utilitarian ethics, since the distribution of happiness and the distribution of the means of happiness are strictly related.