This article discusses the rationality principle, especially in Popper's version, on the occasion of a commentary of Maurice Lagueux's book, Rationality and Explanation in Economics (2010).

When young children confront a vast array of adults' testimonial claims, they should decide which testimony to endorse. If they are unable to immediately verify the content of testimonial assertions, children adopt or reject their informants' statements on the basis of forming trust in the sources of testimony. This kind of trust needs to be based on some underlying reasons. The rational choice theory, which currently dominates the social, cognitive, and psychological sciences, posits that trust should be formed on a (...) rational basis, as a result of probabilistic assessments and utility‐maximizing calculations. In this paper, the predictions stemming from the rational choice approach to trust are systematically compared with the empirical evidence from the field of developmental psychology on how children establish their trust in testimonial statements. The results of this comparison demonstrate an obvious inadequacy of the rational choice explanation of the emergence and development of children's testimonial trust, regardless of which form of trust rationality—weighting, threshold, or ordering—is examined. As none of the three forms of rationality of children's trust in testimony squares with the empirical data, this paper introduces a new version of trust rationality, adaptively rational trust. It explores the compatibility of the concept of adaptively rational trust with the recent empirical findings in the area of developmental psychology and addresses some avenues for future research on the rationality of testimonial trust. (shrink)

Since the early days of economics, the rationality principle has been a core element of economic theorizing. It is part of almost any theoretical framework that economists use to generate knowledge. Despite its central role, the principle’s epistemic status and function continue to be debated between empiricists and rationalists, and a clear winner is yet to emerge. One point of contention is that we cannot explain the principle’s special status in light of clear evidence against its empirical validity and the (...) continuous conceptual changes it undergoes. In this paper, I argue that we should think of the rationality principle as a functional a priori principle along the lines of a pragmatic theory of constitutive elements recently put forward by David Stump. Such an approach would explain the principle’s persistence and changing status. More generally, the pragmatic theory of constitutive elements in science offers a viable alternative to rationalism and empiricism that allows for approaching the debate about the status and function of the rationality principle in economics. It provides a new framework and starting point to think about the usefulness of a central first principle in economics in a constructive way. (shrink)

This paper reconsiders Frank Ramsey's essay on subjective probability (1926) as a consistent way to articulate logic, rationality and knowledge. The first part of the essay builds an axiomatic theory of subjective probability based on ‘formal logic’, defining rationality as choice-consistency. The second part seems to open up different horizons: the evaluation of degrees of belief by ‘human logic’. Because of the interest Keynes (1931) had taken in ‘human logic’, it was considered to be a possible alternative to the formal (...) logic underlying the neoclassical theory of individual behaviour. The analysis of Ramsey's method in the entire paper, the relation between logic and rationality it constructs and the conception of uncertainty it reveals, lead me to note on the contrary that Ramsey's human logic was a complementary logic rather than an alternative to formal logic. Defining a standard to evaluate beliefs formation according to a frequentist criterion, it completes a normative representation of rationality which supports an original theory of knowledge that appears more in line with further developments of neoclassical methodology than with Keynesian economics. (shrink)

Cet article utilise la notion de convention afin de préciser une condition nécessaire à la performation du monde social. On considère ici que l’influence des théories économiques sur le monde social peut être analysée en termes de traduction de conventions scientifiques en conventions sociales. Une telle perspective nous amène à souligner un élément essentiel d’une telle traduction : pour performer le monde social, une notion théorique doit dans un premier temps prendre une posture empirique. On étudie plus particulièrement l’exemple emblématique (...) de la rationalité économique comme concept central d’un nouveau type de politique publique : l’économie des nudges. Classification J.E.L. : B41, C91, Z1. (shrink)