AQUINAS, Saint Thomas, Philosophy of. The philosophy of Saint Thomas Aquinas is the culmination of the philosophic efforts of the Christian schools of the Middle Ages. These schools, dating from their foundation in the reign of Charlemagne, set up a tradition of Aristotelian commentary and of independent speculative activity which, until the middle of the 12th century, were almost entirely circum scribed by the limits of dialectic, or logic. After the middle of the 12th century the physical and metaphysical works of Aristotle (q.v.) became known in the Christian schools of Europe, and with them were introduced Arabian commen taries which interpreted the text of Aristotle in a sense contrary to Christian theism. At the beginning of the 13th century a number of Christian teachers, especially Alexander of Hales and later, Albert the Great, undertook the task of expounding the theistic and spirit ualistic philosophy of the Christian schools on the basis of Aristotle's physical and metaphysi cal doctrines, rejecting from the current Aris totelian teaching whatever they considered to be due to the influence of the Arabian commen tators. These teachers prepared the way for Saint Thomas Aquinas (1225-74), whose chief merit is, not that he created a new method or contributed a new system of thought, but that he gave to the work of his predecessors and contemporaries a more compact synthesis and expounded this synthetic system with a sim plicity and lucidity rarely to be met with in systems which like iris carry complexity to a high degree of organic unity. Saint Thomas' most important works are the contra Gentiles> and the Theologise.' The former, begun at Paris about the year 1257 and completed some time between the years 1261 and 1264, was undertaken at the request of Saint Raymond of Pennafort for the purpose of defending the truths of Christianity against the Arabian pantheists and their followers. It is, therefore, apologetic rather than constructive in method and contents. The Theo logiw> was commenced at Bologna in 1271, and was never completed. Unlike the 'Summa con tra Gentiles,' it is constructive in aim and method. It is Saint Thomas' greatest work, his last and most important contribution to Chris tian theology and philosophy ; for, although the work is entitled 'Summa Theologise' and is, in fact, a compendious treatise on all the ques tions of Catholic theology, it is also a summary of philosophy. It begins with the question of
the existence of God,, treats of the attributes of God, traces the origin of things from God and the return of man to God through Christ. It deals, therefore, with the creation and gov ernment of the universe, with the origin and nature of man, with human destiny, with vir tues, vices and laws — with all the great prob lems of speculative and practical philosophy. It contains the maturer views of its author, so that whenever discrepancies occur between the doctrines of the Summa and the views ex pressed in his earlier works, the Summer is to be taken as the key to the mind of the master.
The method used by Saint Thomas in all his constructive works is a developed and per fected form of the dialectic method which we find anticipated in a short treatise by Gerbert (Pope Sylvester II, died 1003) and of which the first definite example is the Sic et Non of Abilard (d. 1142). In this treatise Abilard presents in contrast the affirmative (Sic) and the negative (Non) opinions of patristic writers in reference to each successive problem of Catholic theology, without, however, furnishing principles by which the discrepancies, real or apparent, are explained. This was, as far as we know, first done by Alexander of Hales (d. 1245), whose method was to set forth the arguments against his thesis, then the argu ments for the thesis and finally to answer the objections. Saint Thomas practically adopted the method as he found it in use in the schools of his day, giving to each article discussed the recognized tripartite division videtur quod non (introducing objections), sed contra (introduc ing the argument for his thesis), and responde tur ad primum, etc. (answers to objections). Underlying this somewhat formal method was the principle which the schoolmen derived from Aristotle, that it is only by the dialectic discussion of the affirmative and negative sides of a question the truth is to be discovered and defined. In other words the faculty of the mind on which philosophy chiefly relies is not intuition but ratiocination.