Abstract

In this work formal systems suitable for the development of a model of inquiry are investigated. We append to a sequent-version of a tableau deductive system new rules for adding formulas to a tableau construction which represent the acquisition of information concerning a given model of the initial premises. These rules may be thought of as enabling an inquirer to ask questions of a source of information about the model. ;We begin by showing how the derivability relation for various of the resulting systems is related to derivability in standard deductive systems. We next look at the way these so-called interrogative systems differ from deductive systems with respect to the basic metatheoretical properties: soundness, completeness, transitivity, etc. We finally begin the development of a theory of interrogative definability, or identifiability