 Maritain’s primary work in epistemology is Distinguer pour unir; ou, les degrés du savoir (1932, Distinguish to Unite: or, The Degrees of Knowledge), though some see Maritain’s 1936 essay, “Science et philosophie” (in Quatre essais sur l’esprit, 1939), in which Maritain addresses arguments of the Vienna Circle, as completing his account of knowledge (Malquori 2009). One also finds a number of important essays on the topic in Raison et raisons, essais détachés (1948, The Range of Reason). Maritain, again, largely follows the realist view of Thomas Aquinas—though he was significantly influenced by John of St Thomas (John Poinsot), St John of the Cross, and St Augustine, and the structure of Les degrés du savoir is similar to the procedure traced in the Itinerarium mentis in Deum [Journey of the Soul into God, 1259 [1938, 2002] of St Bonaventure.