Month: April 2025

How Inference Can Be Explained in Terms of Logical Consequence

Rachel Boddy (IUSS Pavia)

11 April 2025, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão [C201.J] (Departamento de Filosofia)

Abstract: Philosophers have held that validity of inference can be explained in terms of logical consequence. In today’s debate on the normativity of logic, however, it is commonly taken for granted that this view is mistaken. Harman’s (1986) criticism appears to have settled the matter: Current logic fails to explain what beliefs may or should be inferred from what other beliefs. The issue here is that logical principles are not defeasible, whereas principles of belief revision are. I argue that this criticism does not settle the matter because it relies on a notion of inference that logical accounts do not share. The focus of this talk is on the question this raises: What is an inference supposed to be in logic? Starting from the view that inference is an epistemic notion, I argue that the notion of inference at play in logic should be expressed in terms of knowledge, not in terms of belief.

This work/event is funded by Portuguese national funds through FCT – Fundação para a Ciência e a Tecnologia, I.P., within the project UID/00310/2025, Centro de Filosofia da Universidade de Lisboa
(https://doi.org/10.54499/UID/00310/2025)

Subjectless Certainty

Joshua Rowan Thorpe (LanCog, University of Lisbon)

4 April 2025, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão [C201.J] (Departamento de Filosofia)

Abstract: Descartes claims to find certainty in the cogito. Lichtenberg responds: ‘one should say it is thinking, just as one says, it is lightning. To say cogito is already too much as soon as one translates it as I am thinking.’ (Lichtenberg, K 76, translated in Gomes 2024.) Here we have the negative claim that ‘I am thinking’ is not certain. We also have the positive claim that ‘it is thinking’ is certain. The aim of this paper is to assess these claims. I first argue that the negative claim is correct. I also argue that there is something right about the positive claim. We can be certain (only) of the occurrence of something subjectless. However, we should characterise this something in a way that is neutral as to whether it counts as thinking.