The design of an Intelligent Tutoring System (ITS) in a knowledge domain where expertise is modeled as a set of uncertain and incomplete beliefs that are justifiable and expressible in the form of a critical argument is outlined. Issues concerning knowledge communication in a tutorial interaction are discussed with reference to a cognitive model for perception of musical structures, used in an ITS for structural analysis and interpretation of tonal music. A tutorial dialog planning system is outlined that uses sets of context spaces (Reichman 1986) whose discourse function matches possible tutorial actions. Nine figures and a 62-item bibliography are included. (Author/DB)