engleski

Berislav Žarnić (1959-2017)

In `Validity of practical inference' (1999) Žarnić further developed a dynamic logic approach (e.g., Veltman's update semantics) in order to model practical inference. He gave a semantics for goal sentences and factual sentences (Kenny's Fiat and Est sentences), and, ultimately, a natural semantic definition of the validity of practical inference with an appropriate semantic decision procedure. This work is perceived as an important point in the development of the dynamic logic of preference change (cf. van Benthem, `For better or for worse: dynamic logics of preference', 2009). Žarnić revived Lemmon's approach (1965) to the formalization of imperatives on the basis of the von Wright style of logic of change (von Wright 1963). In `Is unsaying polite?' (2012), he developed the semantics of imperative sentences by functionally expressing the cognitive and motivational updates necessary for a required action (cf. `Dynamic models in imperative logic', 2011). He proved the expressive completeness of an imperative language without imperatives to ``produce'' or ``sustain'' non-p (i.e., negated speech acts do not increase the expressiveness of imperative language). This Žarnić's work had been gradually developed starting from papers in 2002 and 2003. For him, logic of utterances, like imperative logic, is the root of logics of intentions (belief, desire), obligation and linguistic commitments (2016). His results in imperative logic have been referred to worldwide in the related work in dynamic logic. Further developing a Broomean set-theoretical approach in normative theory, Žarnić gave a typology of norms by defining the metanormative properties of norm requirements, norm codes, and normative sources (`A logical typology of normative systems', 2010). He formalized ``perfection'' properties (von Wright) of a normative system on the ground of the properties and interrelationship of mutually independent norm set (obligatory content) and counter set (non-obligatory content). On these grounds, he proved various metanormative properties of standard deontic logics, and the perfection or imperfection status of some general principles relating obligation, permission, and forbiddance. These results are presented in several papers from 2014 (with Gabriela Bašić) to 2016. The topics of logic research were for Žarnić intrinsically connected with the philosophy of education. For instance, he shows that learning, if defined as knowledge acquisition in the sense of increase of predictive and explanatory power, is not effectively learnable, although, at the same time, ``learning to learn'' should be preferred to learning a given state of knowledge (`Learning to learn: an epistemological paradox in education', 2001). Žarnić was a co-editor of the Encyclopedia of Educational Philosophy and Theory (1999--2015, online), continuing the collaboration also in the new edition (Springer, 2016- -). Berislav posited high standards and norms not only in his theoretical work but equally in the manner of live, personal communication.

Berislav Žarnić ; dynamic logic ; practical inference ; logic of imperatives ; philosophy of education ; norms ; epistemological paradox

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