Jonas Rafael Becker Arenhart PhD

March 1st - August 27th 2020

Research for a study about

Anti-exceptionalism in logic: a full-blooded approach


Anti-exceptionalism about logic is the view that logic is somehow continuous with science. This implies that accounts of such diverse phenomena as theory choice, theory adequacy, the relation of theory with evidence, and the very nature of theories, in logic, are similar to the cases in science. None of these features sits very comfortably with the traditional view of logic as necessary, universal, and a priori, and none of them have so far been completely articulated in a unified view of the nature of logic, although there is a lot of work currently going on to bring the diverse pieces together. The project addressed some of these issues by developing an account of anti-exceptionalism based on the claim that systems of logic are better understood when regarded as mathematical models, in particular, mathematical models of reasoning in diverse situations. The specific results include:

- an online talk (The problem with ‘the background logic problem’) at the IVC Fellows Moodle Seminar and also, at a later date, for the Group of Logic and Philosophy of Mathematics, at University of Campinas, Brazil, concerning the relation between a system of logic and evidence in favor or against it. We defended the claim that evidence, in the case of logic, is theory laden, just as in empirical science. The disputes about already require that some logical notions be settled, so the locus of disagreement shifts to our goals and purposes in dealing with a given context. A draft of the paper presented at the talk is under revision.

- an online talk (Interpreting philosophical interpretations of paraconsistent logics) at the Iberoamerican Logic Seminar, where it was defended that an appropriate understanding of the difference between pure and applied logics, following an anti-exceptionalist account, may be more suited to the understanding of what is at stake in disputes between dialetheists’ and anti-dialetheists when it comes to paraconsistent logics.

- an online talk (The failure of generalism in a naturalist approach) presented at Logik-Cafe Seminar, University of Vienna, where it was argued that anti-exceptionalism is better accompanied by a kind of relativist and localist approach to logic, instead of a generalist one.

- two accepted papers concerning the relation between formal systems of logic and their intended field of application, discussing, still in a rather indirect way, how a system may fail or succeed in achieving its purported goals.

- A paper on the relation between the a priori/a posteriori distinction and its relation to anti-exceptionalism is currently submitted.


The evidence approach to paraconsistency versus the paraconsistent approach to evidence

Springer; Published: 04/08/2020


Quasi-truth and incomplete information in historical sciences

(Cuasi-verdad e información incompleta en las ciencias históricas)
Jonas R. Becker Arenhart and Vítor Medeiros Costa

DOI: 10.1387/theoria.21254



Online Talk

The problem with ‘the background logic problem

Date: 16/04/2020

Time: 14h00 

Venue: Moodle Collaborate - IVC-Fellowship Talk online

Report to appear

Online Talk:

Interpreting Philosophical Interpretations of Paraconsistency

Date: 28/04/2020,

Time: 17h00 (Vienna time) |12h00 (time Brazil / Argentina)

Venue: at Iberoamerican Logic Seminar

More information:

In this paper, we discuss the meaning of a ‘philosophical interpretation’ of paraconsistent logics. We do so by discussing the epistemic approach, by Carnielli and Rodrigues (2019a), according to which paraconsistent logics must be interpreted exclusively in terms of evidence, and also, by considering counter-arguments by Barrio (2018) and Barrio and da Re (2018), according to whom paraconsistent logics are not specially tied to any specific interpretation. We begin by presenting the positions involved, and by arguing that the debate may be profitably understood in terms of the distinction between pure and applied logics. We argue that dialetheism is not an interpretation of paraconsistent logics, but rather, as soon as one adopts dialetheistic views on truth and negation, a paraconsistent logic is required if logical reasoning is to be studied under these circumstances. Something similar may be said about the epistemic approach. The result is that there is nothing distinctive to be called an interpretation of paraconsistent logics, but rather what we have are distinct applications of paraconsistent logics employing distinct formal semantics relative to each application. Barrio (2018) and Barrio and da Re (2018) arguments may be then re-framed as a skeptical argument against the claim that a unique formal semantics is fixed by the formalism of a paraconsistent logic: given only the rules of a system defining a syntactical notion of consequence, there is no unique semantic frame that these rules pin down as an intended semantics. We conclude by applying the skeptical argument on dialetheism too, in the sense that typical definitions of dialetheism are not enough to escape unintended non-dialetheistic semantics.