The Logic of Internal Rational Agent

In this paper, we introduce a new four-valued logic which may be viewed as a variation on the theme of Kubyshkina and Zaitsev's Logic of Rational Agent \textbf{LRA} \cite{LRA}. We call our logic $ \bf LIRA$ (Logic of Internal Rational Agency). In contrast to \textbf{LRA}, it has three designated values instead of one and a different interpretation of truth values, the same as in Zaitsev and Shramko's bi-facial truth logic \cite{ZS}. This logic may be useful in a situation when according to an agent's point of view (i.e. internal point of view) her/his reasoning is rational, while from the external one it might be not the case. One may use \textbf{LIRA}, if one wants to reconstruct an agent's way of thinking, compare it with respect to the real state of affairs, and understand why an agent thought in this or that way. Moreover, we discuss Kubyshkina and Zaitsev's necessity and possibility operators for \textbf{LRA} definable by means of four-valued Kripke-style semantics and show that, due to two negations (as well as their combination) of \textbf{LRA}, two more possibility operators for \textbf{LRA} can be defined. Then we slightly modify all these modalities to be appropriate for $\bf LIRA$. Finally, we formalize all the truth-functional $ n $-ary extensions of the negation fragment of $\bf LIRA$ (including $\bf LIRA$ itself) as well as their basic modal extension via linear-type natural deduction systems.

Asserting Journalistic Autonomy in the ‘Post-truth’ Era of ‘Alternative Facts’: Lessons from Reporting on the Orations of a Populist Leader

A current challenge for journalists is how to report on post-truth political discourse in an era when the statements of populist leaders are increasingly characterized by emotionalism, out-of-context use of verifiable facts, euphemisms and double speak. A case study of the much-reported maiden speech by populist leader Pauline Hanson to the Australian Senate in 2016 is used to identify trends and patterns in stories that resulted from her oration. The case study findings were used to distil nine recommendations for journalists about how to research and report on statements by high-profile political and opinion leaders who peddle suspected alternative facts and post-truth logic. The findings indicate a need for journalists to reassert their autonomy over storytelling agendas through decoding post-truth discourse to identify underlying news issues, then applying rigour in certain fundamentals of fact checking, information sourcing, framing and backgrounding of stories. The case study findings have international relevance because the politics and media-management strategies of Hanson and her One Nation party replicate those of populist opinion leaders in the United States, United Kingdom and many other countries.

Von Wright’s truth-logic and around

In this paper von Wright’s truth-logic T__ is considered. It seems that it is a De Morgan four-valued logic DM4 (or Belnap’s four-valued logic) with endomorphism e2. In connection with this many other issues are discussed: twin truth operators, a truth-logic with endomorphism g (or logic Tr), the lattice of extensions of DM4, modal logic V2, Craig interpolation property, von Wright–Segerberg’s tense logic W, and so on.

Sentential Falsehood Logic FL4

In some philosophical conceptions, statements are valued as true, false, senseless (neither true nor false), or inconsistent. Falsehood logic FL4 makes it possible to operate correctly by such statements. Logic with falsehood operator FL4 is formulated. For FL4 metatheorems of consistency, deduction and completeness are fulfilled. Correlation between falsehood logic FL4 and four-valued Belnap’s logic and von Wright’s truth logic T"LM is considered. In FL4, the implication for Belnap’s logic is defined so that the truth-valued matrix of it is characterized for logic of tautological consequences Efde. Correlation between three-valued falsehood sublogic FL3N of FL4 and three-valued Kleene’s logic and Lukasiewicz’s logic is considered. Lukasiewicz’s three-valued logic is functionally equivalent to FL3N logic. Correlation between three-valued falsehood sublogic FL3B of FL4 and three-valued paraconsistent Priest’s logic is also considered.