Summae (SUMMULAE), compendiums of theology, philosophy, and canon law which were used both as textbooks in the schools and as books of reference during the Middle Ages. Some historians of theology cite Origen’s peri archon as the first summary of Catholic theology. Others consider that the first in point of time is “De Trinitate” by St. Hilary of Poitiers. Quite recently the distinction has been accorded to Radulfus Ardens, an eleventh-century theologian and preacher, a native of Beaulieu, author of a comprehensive “Speculum Universale”, still in MS. In this wide sense of the word, however, the encyclopedic treatises of St. Isidore, Rabanus, Maurus etc., entitled “De Etymologiis” or “De Universo” might also be considered to be summaries of theology and philosophy. In the stricter sense of the word, “Summa” is applied to the more technical systematic compendiums which began to appear in the twelfth century. An alternative title is “Sentences” (Libri Sententiarum), the diminutive, “Summulae”, being of later origin. What is peculiar to these “summists” or “sententiaries”, as the authors of these works are called, is the adoption of the method first suggested by Gerbert in his “De Rationali et Ratione Uti”, and used by Abelard in his “Sic et Non”. This consisted in an exposition of contradictory views, the affirmative and negative; and progress towards the final form of the thirteenth-century “Summ” is marked by the greater care which was taken, as time went on, to explain in a systematic manner the apparent contradiction among the conflicting opinions presented. Besides this method of exposition, the twelfth-century summists adopted dialectic definitely as a means of elucidating, not only philosophical, but also theological truth. Finally the summists adopted more or less unanimously a fixed division of the field of theology and philosophy, and adhered more or less closely to a definite order of topics. Here, of course, there was room for individual preferences in the matter of arrangement and sequence of problems, as we see when we compare with one another the “Summae” even of the latest period of Scholasticism.
The first great summist was Peter Lombard (died 1160), author of the “Books of Sentences” and surnamed “Master of Sentences”. The order of topics in the “Books of Sentences” is as follows: In the first place, the topics are divided into res and signa, or things and signs. “Things” are subdivided into I. The object of our happiness, God—to this topic Peter devotes the first book; II. Means of attaining this object, viz., creatures—the topic treated in the second book; III. Virtues, men, and angels, that is, special means of happiness and subjects of happiness—the topic of the third book. The fourth book is devoted to signs, namely, the sacraments. How far Peter Lombard was influenced by earlier summists, such as Robert Pullen, Hugh of St. Victor, and the author of the “Summa Sententiarum” which was immediately inspired by Abelard’s work, historians have not determined. It is generally admitted that the Lombard was not entirely original. He deserves his renown as the first great summist chiefly because, in spite of the opposition which his work met during his lifetime, its influence grew greater in time, until in the thirteenth century it was universally adopted as a text. Notwithstanding all that hostile critics of Scholasticism have said about the dryness and unattractiveness of the medieval “Summae”, these works have many merits from the point of view of pedagogy, and a philosophical school which supplements, as Scholasticism did, the compendious treatment of the “Summae” with the looser form of treatment of the “Quaestiones Disputat” and the “Opuscula”, unites in its method of writing the advantages which modern philosophy derives from the combination of textbook and doctor’s dissertation. For a description of the “Summa Theologica” of St. Thomas, the most perfect specimen of this kind of literature, see Thomas Aquinas, Saint. The term “Summulae” was used, for the most part, to designate the logical compendiums which came to be adopted as texts in the schools during the thirteenth century. The best known of these is the “Summul Logicales” of Peter Hispanus, afterwards Pope John XXI.