II-What is the Normative Role of Logic?

Aristotelian Society Supplementary Volume, 2009

The paper tries to spell out a connection between deductive logic and rationality, against Harman's arguments that there is no such connection, and also against the thought that any such connection would preclude rational change in logic. One might not need to connect logic to rationality if one could view logic as the science of what preserves truth by a certain kind of necessity (or by necessity plus logical form); but the paper points out a serious obstacle to any such view.

Rough draft. To appear in Knauff, M. and Spohn, W. (ed.), Handbook of Rationality, MIT Press.

This chapter addresses the question as to how (if at all) propositional (PL) and first-order logic (FOL) relate to epistemic rationality. Rationality, it is often held, demands that our attitudes cohere in particular ways. Logic is often invoked as a source of such coherence requirements when it comes to belief: An ideally rational agent's beliefs are consistent and closed under logical consequence. However, this traditional picture has been challenged from various quarters. We begin by briefly reviewing the key concepts involved in PL and FOL. We then critically examine two distinct approaches to justifying logic-based requirements of rationality. The first lays down a set of desiderata codifying our intuitions, and then seeks to formulate a principle articulating the link between logic and rational belief that satisfies them. The second starts by identifying our most fundamental epistemic aim and seeks to derive requirements of rationality based on their ability to promote this aim.

Theoria. An International Journal for Theory, History and Foundations of Science, 2023

This paper advocates for the normative role of logic in reasoning. I offer a response, anchored in an externalist perspective, to two fronts of attack against the normativity thesis, namely Harman’s sceptical challenge and the accusation of naturalistic fallacy. On the one hand, I rework dialogical bridge principles and show that such principles satisfy adequacy criteria to deal with Harman’s challenge. On the other hand, I argue that it is possible to derive normative consequences from logical facts. This is because argumentative interactions among agents involve the acceptance of constitutive rules that entail obligations. Hence, since logical rules can be seen as constitutive of the social practice of reasoning, they create prescriptions for reasoning. Bridge principles make those obligations and prohibitions explicit.

Proceedings of the Aristotelian Society (Hardback), 2009

Frontiers in Psychology, 2014

1997

New Ideas in Psychology 16 (1998) 125-139

This is our response to the commentaries on the paper on the logical substantiation of our theory.

Philosophies, 2017

In this paper, it is examined how, if at all, the logical laws can be normative for human reasoning, wherein the notion of normativity is analyzed primarily with respect to Wittgenstein's philosophy. During the ancient and the medieval periods, logic was being considered in terms of discourse and dialogical practice, but since Descartes and especially Kant, it has been treated as a system of laws with which the process of individual human reasoning has been compared. Therefore, normativity can be investigated in the private sphere (for thinking and reasoning) and in the public sphere (for dialogic practices in a community). Wittgenstein discussed both aspects of normativity: in his early philosophy, the focus is on the laws of logic that are primarily normative for the state of affairs in the world, while in his later works the emphasis is on a social aspect of normativity (which is closer to Aristotle's view), which is derived from the adopted rules that have been applied in a certain community. Taken that way, logic is certainly normative in the public sphere, but the more difficult issue is whether logic is normative for thinking, regarding the difference between the logical laws and those of thought.