Segundo Workshop IIF-UNAM – BA-Logic de Lógica Filosófica

The minimalist strategy for finding counter-examples to logical rules that Gillian Russell illustrates with her use of PREM and SOLO statements is generalized to any basic, normal formal rule and developed in a way that evades Dicher’s response. A response is also developed that suggests that Russell-like counter-examples are easily avoidable products of notational conventions.

Luis Estrada González: “Every argument is invalid (and the trivial world is not to be blamed)”

In recent years it has been circulating an argument to the effect that the inclusion of a trivial world, t, in one’s semantics leads to the invalidity of all arguments. In this talk, I will show that such an argument is unsound. Moreover, I will show that, in using a certain form of non-classical meta-theory, one can end up invalidating all arguments even without t.

Elisángela Ramírez (with Fernando Cano-Jorge): “What makes a confirmation theory plausible?”

We will consider Hempel’s requirements for any plausible formal theory of confirmation as the current standard of evaluation for such theories. These requirements are: (1) there should be a finite list of the formal properties of the confirmation relation; (2) recognition that the heart of the issue lies in the adequate formalization of universal conditional statements; and (3) candidate theories should remain as close as possible to the standard logical theory, on pain of invalidating widely adopted inferences.

We will point out that the Crupi and Iacona’s evidential conditional is constrained by concerns similar to those listed above. Discussing the evidential conditional will also bring out the conflict between (2) and (3): preserving classicality blocks nearly every available road towards a logical solution to the paradoxes of confirmation. In addition, there seem to be no reasons for rejecting logical solutions to the paradoxes other than the preservation of classicality. As a point of comparison, we will argue that a theory based on the ideas of Sylvan and his collaborators makes for a worthy contender in the search for a plausible theory of confirmation, even if it is not focused on the preservation of the standard logical theory.

Christian Romero: “Everything is true, “Everything is true” And their consequences”

A trivialist is an agent defined (at least hypothetically) as follows:

Trivialist1:: An agent a is a trivialist if and only if, for every proposition A, a believes that A.

In On the Plenitude of Truth (2010), Paul Kabay defends two theses:

(T1): There are no antitrivialists because there are no agents who are able to perform the speech act of denying trivialism, since there are no speech acts which are incompatible with speech acts of the trivialist.
(T2): A trivialist can act with purposeful behavior, despite the objections of Aristotle and Priest (2006).

I argue that (T1) and (T2) are incompatible, in the sense that the argument for (T2) requires a definition of ‘trivialist’ other than (Trivialist1) that allows one to conclude that there are in fact no trivialists, that is, that allows one to reject (T1); whereas if one keeps the original definition to hold (T1), there is no way to meet Priest’s objections, that is, no way to hold (T2).

Miguel Álvarez Lisboa: “Intuitionistic logic from a metainferential perspective”

The so-called Buenos Aires Plan affirms, among other things, that a logic should not be only identified with a set of inferences but also of meta-inferences of every level. This metainferentialist conception of logic has gained notoriety in the last years, specially among those who study semantic paradoxes. But it is clear that its scope is broader. Thus, my purpose is to investigate the consequences of applying this perspective to characterize intuitionistic logic. In this presentation I will give a short philosophical justification of this move, together with a metainferential presentation of intuitionistic propositional logic and some metalogic results.

Federico Pailos (with Camillo Fiore and Eliana Francescini): “Supra-structural logics”

A structural principle is one in the formulation of which no logical constant of the object language is mentioned. Over the last few years, much attention has been paid to substructural logics, understood as systems that invalidate at least one classically valid structural principle. It is noteworthy, however, that little or no attention has been paid to what we might call suprastructural logics, or systems that validate at least one classically invalid structural principle. In this paper, we explore several such systems.

Mariela Rubin: “Trivalent conditionals and the non propositional thesis”

The aim of this work is to defend a three-valued semantics to model the behavior of the indicative conditional based on the truth tables and the probabilistic calculus originally proposed by De Finetti in 1936. Yet, I will defend, in line with Adams, (1965, 1975), Edgington (1995) and, Bennett (2003), that indicative conditional does not express a proposition, but the degree of confidence in the consequent in case the antecedent happens to be true. The main thesis to defend is that De Finetti’s proposal implies a non-propositional reading of the conditional, although the literature that followed him interpreted it oppositely. At the same time, I will argue that the non-propositional reading of the indicative conditional is not only compatible with this trivalued semantic but it also allows the thesis to enrich its syntax and semantics by allowing conditionals to be sub-formulas of any formula of the language.

Damian Szmuc (with Bruno da Re): “Non-reflexive Nonsense”

The aim of this paper is to provide a sequent calculus whose external consequence relation coincides with the three-valued paracomplete logic of ‘of nonsense’ B3 introduced by Bochvar (1938). One of the main features of this calculus is that it does not contain any restrictions on the application of the rules. Also, the technique developed to prove completeness is a generalization of the reduction-tree method.

ORGANIZERS

Eduardo Barrio (IIF-SADAF-CONICET/UBA)

Luis Estrada González (IIF-UNAM)