Fr. Regis Armstrong writes as follows in footnote 191 (on part 3 of book 3) of his translated and annotated edition of St. Bonaventure’s Itinerarium Mentis in Deum:
The presence of this formula, “one, true, and good,” stands out in the writings of the “giants” of the thirteenth century: the Franciscans—Alexander of Hales, Bonaventure, and Scotus—and the Dominicans—Albertus Magnus and Thomas Aquinas. All of these may well have been influenced by Philip the Chancellor (c. 1160-1236), who had taken as the starting point of his Summa de bono the creation account of Genesis 1—2:3, particularly the phrase “God saw it was good.” Philip consequently took goodness as the organizing principle for his work. This approach reconciles the seemingly contradictory scriptural texts, provided a model for his metaphysics and ethics, and introduced the first scholastic treatment of the transcendentals. Alexander of Hales devoted the first part of his Summa to “the divine unity, truth, and goodness.” Whereas Philip had written of these as “the most common principles” (communissima), Alexander’s Summa described them as “first intentions” (primae intentiones) and “first impressions” (primae impressiones), arguing that first notions cannot be defined or made known by something prior to them.
In the Breviloquium Bonaventure had written: “Since the First Principle is the most exalted and utterly perfect, it follows that in it are found the highest and most universal properties of being to the highest degree. These are the one, the true, and the good, which are not associated with being in its supposits but with its very principle. For ‘one’ describes being as numerable, and this is because it is not susceptible of division in itself; ‘true,’ as intelligible, and this by virtue of being inseparable from its proper form; and ‘good,’ as communicable, and this by reason of being inseparable from its proper operation. This triple indivisibility has a logical ordering in that the true presupposes the one, and the good presupposes the one as well as the true.” He continues in that trinitarian vein: “Thus it follows that these three qualities, as being perfect and transcendental, are attributed to the First Principle to the highest degree, and, as having an orderly reference, are attributed to the three persons. It follows, then, that supreme oneness is attributed to the Father; supreme truth, to the Son who proceeds from the Father as his Word; and supreme goodness, to the Holy Spirit who proceeds from both as their Love and Gift.”
Source: Fr. Regis Armstrong, OFM Cap., Into God: Itinerarium Mentis in Deum of Saint Bonaventure, An Annotated Translation 261-62 (CUA Press 2020).
