This book contains a selection of the papers presented at the Logic, Reasoning and Rationality 2010 conference in Ghent. The conference aimed at stimulating the use of formal frameworks to explicate concrete cases of human reasoning, and conversely, to challenge scholars in formal studies by presenting them with interesting new cases of actual reasoning. According to the members of the Wiener Kreis, there was a strong connection between logic, reasoning, and rationality and that human reasoning is rational in so far (...) as it is based on logic. Later, this belief came under attack and logic was deemed inadequate to explicate actual cases of human reasoning. Today, there is a growing interest in reconnecting logic, reasoning and rationality. A central motor for this change was the development of non-classical logics and non-classical formal frameworks. The book contains contributions in various non-classical formal frameworks, case studies that enhance our apprehension of concrete reasoning patterns, and studies of the philosophical implications for our understanding of the notions of rationality. (shrink)

In this first section we start with defining the notions of inconsistency and para-consistency, we give an example of an inconsistency and clarify what according to us is the basic problem with respect to the occurrence of inconsistencies. We are then in a position to state the aim of this paper.

The aim of the paper is to introduce the concept of adaptive logics (AL) or rather adaptive logical approach. In the introduction, a motivation and an emergence of AL are briefly discussed. In the second part of the paper, specifics of AL are analysed – especially nonmonotonic character, internal and external dynamics, as well as the structure of AL, namely the distinction between upper limit logic and lower limit logic. In this part, the dynamic proof is also described. Applications of (...) AL are presented in the third part. Three illustrations from three different branches of philosophy are presented. First one is an illustration of description of science – a traditional application of AL. Second one is an illustration of solving a deontic conflict – this is a new direction within in AL which has recently been researched. Third one is an illustration of analyses of metaphors – an example of an unusual application of AL. In the conclusion of the paper, contemporary results of AL are critically evaluated with respect to some problems of the project of AL. (shrink)

Inconsistency toleration is the phenomenon of working with inconsistent information without threatening one’s rationality. Here I address the role that ignorance plays for the tolerance of contradictions in the empirical sciences. In particular, I contend that there are two types of ignorance that, when present, can make epistemic agents to be rationally inclined to tolerate a contradiction. The first is factual ignorance, understood as temporary undecidability of the truth values of the conflicting propositions. The second is what I call “ignorance (...) of theoretical structure”, which is lack of knowledge of relevant inference patterns within a specific theory. I argue that these two types of ignorance can be explanatory of the scientists’ rational disposition to be tolerant towards contradictions, and I illustrate this with a case study from neutrino physics. (shrink)

. This paper proposes a generalization of the theory of the process of explanation to include consistent as well as inconsistent situations. The generalization is strong, for example in the sense that, if the background theory and the initial conditions are consistent, it leads to precisely the same results as the theory from the lead paper (Halonen and Hintikka 2004). The paper presupposes (and refers to arguments for the view that) inconsistencies constitute problems and that scientists try to resolve them.