In discussing Dr. Giuseppe Civitarese’s papers, “The Concepts of O: Is Bion a Mystic?” (2017) and “Bion’s O and His Pseudo-Mystical Path” (based on the former, in this issue), the author clarifies Civitarese’s claim that concept of O founds psychoanalysis on a pragmatic, intersubjective and aesthetic theory of truth and the growth of the mind. She explains how Civitarese uses Bion’s concepts of “at-one-ment” and “feeling together” as the basis of truth and knowledge more generally but also for how the mind grows developmentally and clinically. In addition, the author explicates how for Civitarese, this view of the concept of O moves our interest away from the infinite of the unknown of nature to the infinite of the unknown of human meaning. Finally, the author demonstrates how transformations in O seen in this way are manifested in the clinical encounter and gives an extended clinical example that highlights these points.