Title: Analyticity, suppositional reasoning and the a priori
AbstractIn this paper I argue that we have good reasons to reject analyticity accounts of a priori knowledge. A priori knowledge is not grounded on sheer conceptual understanding or implicit definitions. After I discuss the relevant objections to analyticity accounts, I sketch an alternative account of a priori knowledge. Roughly, the alternative says that suppositional reasoning is a source of a priori knowledge.

______________________________________In the past:_______________________________________
Title: Knowledge of validity
Abstract: In logic we make claims such as 'Excluded-middle is a logical truth' and 'Modus ponens is logically valid'. These claims are (at least implicitly) universal claims: they are about (infinitely many) sentences or arguments that share the same logical form. How can we know that those claims are true, though? Tradition has it that our knowledge of logical truths is in some sense grounded on pure thought: deductive reasoning plus rational intuitions (if you're a rationalist) or maybe definitions (if you're an empiricist). But can we have knowledge of the fact that the target sentence-/argument-forms are valid without already presupposing that they are so, thus arguing in circles? In this talk I will investigate into the nature of logical knowledge and the problem of rule-circularity.

14-16.06.2016The Normativity of Logic, University of Bergen.
Title: Ways in which logic was supposed to be special, but ain't
AbstractI discuss Harman’s (1986) arguments to the effect that logic is not especially relevant to the normativity of reasoning, and I contend that Harman’s points do not establish that conclusion after all. That observation notwithstanding, I will argue that the strength and scope of logic-based norms of reasoning is no different from the strength and scope of norms of reasoning that are grounded on non-logical metaphysical truths. Consequently, even if logical principles are maximally normatively binding (and there are good reasons to think that they are), that gives no support to the claim that logic occupies a special place in the normativity of reasoning.

18-19.05.2017Reasoning Club 2017, Center for Logic, Language and Cognition, Torino.
Title: Knowledge grounded on pure reasoning

04-06.04.2017, UConn Logic Group/MCMP Workshop in Storrs, University of Connecticut.
Title: The Epistemology of Logic and Logical Pluralism
AbstractEpistemological accounts of logical knowledge face the following challenge. They must either (a) explain how it is possible for people to hold conflicting logical beliefs in an epistemically warranted way, or they must (b) explain why only one of the conflicting logical beliefs can be warranted (e.g. perhaps no one can ever be warranted in believing that modus ponens is invalid), or rather they must (c) show that disagreements in logic are only apparent, in that the disagreeing parts do not really hold conflicting logical beliefs. In this paper I will argue that, even though strategy (c) is sometimes called for, most of the time (a) is the right choice. Furthermore, that gives us a reason to be pluralists about logical consequence.

15.12.2016The Third Lisbon Conference on Philosophy of Science, Universidade de Lisboa.
Title: The epistemology of logic and logical pluralism
Abstract: I will argue that rational disagreements about logical principles is possible, and that this motivates a certain type of logical pluralism. An account of how logical beliefs can be warranted is presented. It roughly says that logical beliefs may be reliably formed on the basis of certain pieces of suppositional reasoning, and that this makes it possible for different people to form different logical beliefs.

19.11.2016Workshop: The Relevance of Logic to Human Reasoning, Munich Center for Mathematical Philosophy.
Title: When reasoners go offline. This workshop was organized by me and my colleague Andreas Kapsner.

10.09.2016, Colloquium Logicum 2016, Universität Hamburg. 
TitleA framework for testing the relevance of logic to reasoning 
AbstractMuch has been discussed lately about the relevance of logic to the normativity of human reasoning (both, in the epistemology literature and in the cognitive psychology literature). In this presentation, we will flesh out a semantic framework that allows us to test whether and to what extent certain logical systems are normatively binding with respect to human reasoning. The framework uses families of models that represent the cognitive situations of reasoners. It is then possible to change the reasoner's inferential accessibility relations in accordance with different logics, which will give rise to alternative verdicts as to what is rational for the reasoner to believe or doubt. As we expect to show, logic can be relevant to the normativity of human reasoning after all -- but only if we accept a certain form of logical pluralism.

29.08.2016, Logic, Meaning and Language, The Hebrew University of Jerusalem.
Title: Reliable reasoning in natural language
Abstract: It is relatively easy to say when reasoning in formal languages is reliable, e.g. using model-theoretic semantics. But whatever we say to that effect will be concerned with an artificial notion of reliability in reasoning (basically there is a big difference between truth and truth-in-a-model), and it won’t deliver, or at least not immediately, an answer to the question: when is reasoning in natural language reliable? That is the question I am going to address here. I will flesh out a reliability-entailing condition for reasoning in natural language that allows us to be neutral on what is the logical form/structure of natural-language sentences.

08.04.2016, Roots of Deduction Workshop, University of Groningen.
Title: Warranted Logical Beliefs
Abstract: In this talk, I present an account of how certain types of logical beliefs can be non-empirically warranted when they are not inferred from other warranted beliefs. Roughly put, the account says that pure reasoning is a source of warrant for logical beliefs. More precisely stated, the idea is that one may reliably perform inferences on the basis of pieces of suppositional reasoning. Since the truth of that claim depends on the assumption that there are reliable belief-forming processes of the relevant kind, I also present a (satisfiable) condition whose satisfaction entails that to be so.

31.08.2015, Colloquium: Richard Swinburne, Pontifícia Universidade Católica (Porto Alegre, Brazil).
Title: It is unlikely that God exists
Abstract: I argue that theists face basically the same problem that substance dualists do (concerning the causal interaction between the physical and the non-physical). That makes both the prior probability and the likelihood of theism -- when this hypothesis is conceived as an explanatory hypothesis -- quite low.

24.07.2015Buenos Aires Logic Group WIP Seminar, University of Buenos Aires.
Title: A logic of offline rationality
Abstract: What are the epistemic principles regarding what is rational for subjects to believe when they 'go offline', i.e. when they stop gathering new information and start processing the information they already have available? In this talk, I flesh out a model-theoretic semantics that validates certain principles of offline rationality. I show that the epistemic logics that are thereby derived can be used against our normative intuitions in specific ways.