Abstract : This introduction to a special issue on "Normes and normativity" emphasizes the difficulties and challenges of distinguishing between a positive approach and a normative approach to norms in economics. Collective life is organized by norms, however the mere fact that they regularly influence behaviours does not imply their desirability. A strict description of norms may require consideration of ethical issues, which may be reported by different methods; choosing among norms however is an activity of a fundamentally normative nature, (...) which questions the legitimacy of decisions and evaluations. The very possibility of a demarcation between is and ought is not straightforward. In welfare economics in particular, the standard approaches that aim to avoid value judgements (welfarism) or to isolate them (axiomatics) can be problematic. To conclude, we present the four articles in the special issue meant to illustrate these issues regarding the nature, knowledge, value of norms and the positive-normative distinction. -/- Résumé : Cette introduction à un dossier thématique sur le thème "Normes et normativité" insiste sur les difficultés et les enjeux de la distinction entre les approches positives et normatives des normes en économie. La vie collective est organisée par des normes, mais qu’elles ordonnent les comportements dans les faits n’impliquent pas qu’elles soient désirables. Une stricte description des normes peut nécessiter de prendre en compte les questions éthiques, lesquelles peuvent être traduites par différentes méthodes ; choisir les normes en revanche est une activité de nature fondamentalement normative, qui interroge la légitimité des décisions et des évaluations. La possibilité même de démarcation entre positif et normatif ne va pas de soi : en particulier en économie du bien-être, les approches standards qui visent à éviter les jugements de valeur (le welfarisme) ou à les isoler (l’axiomatique) peuvent s’avérer problématiques. Pour conclure, nous présentons les quatre articles du numéro qui illustrent ces questionnements relatifs à la nature, la connaissance, la valeur des normes et la distinction entre normatif et positif. (shrink)

The aim of this article is to question the epistemic presuppositions of applying behavioural science in public policymaking. Philosophers of science who have examined the recent applications of the behavioural sciences to policy have contributed to discussions on causation, evidence, and randomised controlled trials. These have focused on epistemological and methodological questions about the reliability of scientific evidence and the conditions under which we can predict that a policy informed by behavioural research will achieve the policymakers’ goals. This paper argues (...) that the philosophical work of Helen Longino can also help us to have a better and fuller understanding of the knowledge which the behavioural sciences provide. The paper advances an analysis of the knowledge claims that are made in the context of policy applications of behavioural science and compares them with the behavioural research on which they are based. This allows us to show that behavioural policy and the debates accompanying it are based on an oversimplified understanding of what knowledge behavioural science actually provides. Recognising this problem is important as arguments that justify reliance on the behavioural sciences in policy typically presume this simplification. (shrink)