Aquinas was not merely a theologian in a narrow and restricted sense of that word, but was also noted as a commentator on Aristotle.[1976] Ptolemy of Lucca tells us that “he expounded practically all philosophy, whether moral or natural, but especially ethics and mathematics.” These lectures, however, were not all published. Thomas did not comment on as many of the Aristotelian works as Albert did, and several of his commentaries were left unfinished and were completed by others such as Peter of Auvergne. Thomas has sometimes been given credit for bringing about and using as the basis of his commentaries a new translation of Aristotle, made directly from the Greek and presumably executed by William of Moerbeke,[1977] although, as we have already noted in the case of Peter of Prussia’s Life of Albertus Magnus, some say by Thomas of Cantimpré. It is true that William of Moerbeke translated some of the works of Aristotle, but I cannot find that anyone has ever identified a signed translation by him with the text used by Aquinas or otherwise adequately demonstrated that they worked in concert.[1978] Even if Aquinas instigated William’s translations from Aristotle, he could not have taken full advantage of them, since some of William’s work of translation was executed after Aquinas’ death.[1979]
The spheres of theology and science.
We must not think of Aquinas’ studies in secular philosophy and science as simply aimed to render these subjects serviceable and innocuous to Christian theology. He was too much a student of Albertus Magnus for that, and his study of Greek thought and natural science broadened his outlook beyond that of theology in a narrow sense. He believed, moreover, that to a large extent the fields of theology and natural science were distinct; that pure theologians should not try to settle purely philosophical or scientific problems, of which they knew little. Christians who deny as contrary to their faith the philosophical solutions of problems which are really indifferent so far as the Faith is concerned, simply bring Christianity, in Aquinas’ opinion, into disrepute among the wise men of this world.[1980] Conversely every theory of an ancient philosopher or hypothesis of science is not to be accepted as of equal rank with religious dogmas. When John of Vercelli submitted a list of questions upon which he desired, first, the opinions of the saints, and secondly, the opinion of Aquinas himself, Thomas protested at the start that some of the inquiries had nothing to do with the Christian faith but were purely physical.[1981]
Aquinas as a scientist.
Furthermore we must keep in mind that Aquinas was something of a scientist himself. It is interesting to note that after his death the University of Paris wrote to the general chapter of the Dominicans, not only lamenting his death as an irreparable loss and asking that his bones might be sent to Paris for burial, but also requesting the transmission of certain books begun by him while at the university and not as yet completed upon his departure from Paris.[1982] What were these writings: theological treatises, commentaries on the minor prophets, or manuals of devotion? None of these. They were a commentary on the philosopher Simplicius, another on the De coelo et mundo of Aristotle,[1983] a third on the Timaeus of Plato, and finally a work on irrigation and mechanical engineering.[1984]
Inferior to Albert.
Thomas, however, did no such important work in natural science as Albert. His commentaries upon Aristotle follow the text closely and do little more than expound it; they are not full of long digressions and additions, as Albert’s are. Thomas did not found an experimental school and had not himself devoted the long years of personal experience and observation to nature that his master had. And he seems to have had the less original and observant mind of the two. But his wide reading, his clear thinking, his well-ordered class-room presentation of material and arguments, and his broad yet moderate views insured his instant and permanent success in the field of theology, where the paths were already well trod, and it only remained for someone to put everything into as perfect and final a form as possible. In natural science, on the other hand, the labor that awaited men was not merely the lucid combination of Aristotelian and Arabic thinking with previous Christian thought, but the pioneer work of personal observation and experiment and the far more difficult combination of these with existing theories. Aquinas was a perfecter according to the standards of his own age; Albert sometimes was a pioneer in the spirit of the new age of science.
Aquinas’ theological approach to the subject of magic.
In view of this distinction between the two men it is perhaps not surprising that what Aquinas has to say concerning magic, even in the broad use of that term, occurs to a large extent in his theological writings. Just as, although Albert was a distinguished theologian, we viewed magic in his works largely as connected with science; so, although Aquinas studied and wrote of secular philosophy and science, we find in him a moderate, enlightened, and highly influential statement of the attitude of Christian theological scholarship towards magic, witchcraft, and astrology. In his account of magic so-called in his Summa, Contra Gentiles, and De potentia, he seems to follow Augustine a good deal, and like him he makes considerable use of Porphyry’s Letter to Anebo. Aquinas accepts the essential features of the previous theological definition of magic, as Albert did in his theological treatises.
Miracle distinguished.