In the framework of medieval Christianity, their closeness is much more apparent than their opposition. There are those who believe that the universal authority of Saint Thomas overshadows that of the equally great Saint Bonaventure. In fact, however, Bonaventure by his inspired genius seems to respond more genuinely and more deeply to some of the exigencies of modern thought. Plainly, his ontology of participation and essence, derived from Plato through Augustine, Dionysius the Pseudo-Areopagite, and Hugh of Saint-Victor, does not have the same ring as Thomas' ontology of being and efficient causality. The Summa theologica represents the consummate mastery of theological data; it is the most coherent work available to the Christian as a means of understanding his Faith. In contrast, Bonaventure never considers the goal as being attained: he expresses faith in its upward surge, and sees understanding as a constant quest. Here, we recognize the "ascension" of Plato, which Augustine explained in terms of the constant striving of the Christian soul. This, perhaps, is what gives Bonaventure an original place even among the great Doctors of the Church, with whom he ranks in virtue of his religious and speculative genius.
--Bougerol, Introduction to the Works of Bonaventure