Defeasibility and Practical Errors

Defeasibility is usually understood as the possibility that rules contain implicit exceptions. It is a problem that has generated a wide bibliography in the last decades, normally linked to analytic legal positivism. The present paper will deal with the matter of defeasibility as a theoretical problem, that is, a problem of the theories of law. In particular, two of the most refined proposals of contemporary legal positivism will be analyzed: the deep conventionalism of Juan Carlos Bayón and the inclusive legal positivism of José Juan Moreso and his theory of defeaters. Once these positions have been analyzed, the basic theses of legal postpositivism will be presented, highlighting the idea of practical error, showing how for legal postpositivism the problem of defeasibility is nothing other than that of the rationality of legal decisions, of making implicit law explicit, and that in this regard there are rational criteria that help us to solve hard cases and avoid making practical errors

The Evolution of Defeaters: A Taxonomy

It has been widely argued that reasons for a belief come in degrees but not much literature has focused on the idea that defeaters for justification toward those beliefs also come in degrees. The aim of this paper is to explore epistemic defeasibility and construct a taxonomy for epistemic defeaters. This paper argues that epistemic defeaters undergo an evolutionary process before becoming what they are commonly labeled, such as rebutting and undercutting. I argue that within some stages of this process, there can be different degrees of defeat. This paper focuses on defeaters for justification, expands on the account of partial defeaters and offers a solution to reliabilism’s problem with defeat. The main aim of this taxonomy is to provide a framework that allows (most) epistemic theories to accept solely on the basis of epistemic defeasibility

Defeaters and practical knowledge

This article shows that the problem of defeasibility hinges on a more fundamental issue about the source of authority of moral reasons. It argues that the legitimate source of moral authority is rationality, and that rational justification deploys universal principles. However, normative defeasibility raises important issues about the possibility of practical inferences. As an alternative, a non standard version of Kantian constructivism is defended