Weight of evidence continues to be a powerful metaphor within formal approaches to epistemology. But attempts to construe the metaphor in precise and useful ways have encountered formidable obstacles. This paper shows that two quite different understandings of evidential weight can be traced back to one 1878 article by C.S. Peirce. One conception, often associated with I.J. Good, measures the balance or net weight of evidence, while the other, generally associated with J.M. Keynes, measures the gross weight of evidence. Conflations (...) of these two notions have contributed to misunderstandings in the literature on weight. This paper shows why Peirce developed each conception of weight, why he distinguished them, and why they are easily mistaken for one another. (shrink)

La justification des croyances peut être de nature pragmatique – à savoir, une justification qui dépende des enjeux pratiques de la situation dans laquelle le sujet ayant une certaine croyance se trouve. De plus, dans des contextes spécifiques, comme par exemple le contexte juridique, il y a des cas où une connaissance est attribuée à un sujet ayant une croyance vraie en faisant abstraction de la justification qu’il peut avoir ou non à propos de sa croyance. Dans ces cas, l’attribution (...) de connaissance est justifiée par les enjeux pratiques de la situation, de façon analogue à celle où une croyance est justifiée par un critère pragmatique.The pragmatic justification of beliefs may be of pragmatic nature, namely a justification which depends on practical stakes in the situation in which the subject having a certain belief finds himself. Furthermore, in specific contexts, as for example the legal context, there are cases where a knowledge is granted to a subject having a true belief by disregarding the justification which he can have or not about his belief. In those case, the attribution of knowledge is justified by the practical stakes of the situation, in a similar way to that where a belief becomes justified by a pragmatic criterion. (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)

Normative ethics usually presupposes background accounts of human agency, and although different ethical theorists might have different pictures of human agency in mind, there is still something like a standard account that most of mainstream normative ethics can be understood to rest on. Ethical theorists tend to have Rational Man, or at least some close relative to him, in mind when constructing normative theories. It will be argued here that empirical findings raise doubts about the accuracy of this kind of (...) account; human beings fall too far short of ideals of rationality for it to be meaningful to devise normative ideals within such a framework. Instead, it is suggested, normative ethics could be conducted more profitably if the idea of unifying all ethical concerns into one theoretical account is abandoned. This disunity of ethical theorizing would then match the disunited and heuristic-oriented nature of our agency. (shrink)