A logical analysis of instrumentality judgments: means-end relations in the context of experience and expectations

This article proposes the use of temporal logic for an analysis of instrumentality inspired by the work of G.H. von Wright. The first part of the article contains the philosophical foundations: in particular, we discuss Von Wright's general theory of agency and his account of instrumentality. Moreover, we provide several refinements of this framework via rigorous definitions of the core notions involved. In the second part, we develop a logical system called TLAE (Temporal Logic of Action and Expectations), which is inspired by a fragment of propositional dynamic logic and based on indeterministic time. We prove this system to be weakly complete relative to a given axiomatisation and then use it to formalise the instrumentality relations defined in the first part of the paper. Last, we point out some philosophical implications of our work and suggest ways in which our formalism could be employed in deontic settings.