The primary place held by Scripture in the theology of Irenaeus of Lyons is beyond doubt. A number of scholars have pointed out, however, that Irenaeus also utilizes philosophy and rhetoric to his advantage. Despite the gains of this research there is a persistent tendency to trivialize Irenaeus’ philosophical and rhetorical ability. In this paper I argue against this tendency by calling more attention to the philosophical ability that Irenaeus displays. In the first place, I summarize the current state of scholarly opinion on the role of philosophy and rhetoric in Irenaeus’ thought. In the second, I illustrate Irenaeus’ use of philosophy by examining his comments in Against Heresies 3,24,2-3,25,5.