This chapter explores the initial phase of the author’s tutelage in Caesarea, one well known from the traditional Greco-Roman curriculum of encyclical studies (enkyklios paideia): dialectic, the training in the logical and precise analysis of articulation, and argumentation. This is described both as an investigation of the natural abilities of the student and a thoroughgoing process of breaking down acquired habits of thought and speech. These are examined in light of Origen’s own views as expressed throughout his works, as well as in the writings of earlier exponents of the Alexandrian theological tradition (Philo, Clement) and within contemporary philosophical, especially Platonic, traditions (Alcinous). This emphasis on dialectical training as a corrective to enclosed or habitual attitudes is coordinated with Origen’s striking understanding of a heresy as primarily a dogmatic or exclusivist system of thought and belief. His opposition to this sort of blind allegiance finds a number of interesting parallels, particularly in the writings of Galen of Pergamum.