In Fides et Ratio, Pope John Paul II tells us that “A quite special place …belongs to Saint Thomas, not only because of what he taught but also because of the dialogue which he undertook with the Arab and Jewish thought of his time. In an age when Christian thinkers were rediscovering the treasures of ancient philosophy, and more particularly of Aristotle, Thomas had the great merit of giving pride of place to the harmony which exists between faith and reason. Both the light of reason and the light of faith come from God, he argued; hence there can be no contradiction between them.”
The natural dictates of reason must certainly be quite true: it is impossible to think of their being otherwise. Nor again is it permissible to believe that the tenets of faith are false, being so evidently confirmed by God. Since therefore falsehood alone is contrary to truth, it is impossible for the truth of faith to be contrary to principles known by natural reason. (SCG 1, 7)
In defending both faith and reason, St. Thomas Aquinas found himself fighting a two front war. There were traditionalists who thought Aristotle a danger to the orthodox faith, and there were those who seemed almost to disregard matters of faith in defending the genius of Aristotle and his works. Thomas view of the controversies could be summed up in the advice he gave to one ‘Brother John’: “Never mind who says what, but commit to memory what is said that is true: work to understand what you read, and make yourself sure of doubtful points.”
For Thomas, the truth was one, and whether it was come to by a pagan or a Christian, whether by revelation or by reason alone, truth was truth. We can learn truth from the pagans without adopting their errors. Indeed, reason helps us to see if we are clearly understanding revelation, and revelation will keep us from erring in our reason on certain points (or at least by helping us see that “reason” has reached its limit, beyond which truth can only be known by revelation, so as to avoid the errors of rationalism).
St. Thomas disputed with Latin Averroism, a controversy said to teach Aristotle in its original form, with no reconciliation to the Christian faith in places where it was in conflict (or was perceived to be, based on the commentaries of certain Arabic philosophers) with the Catholic faith. For example, Siger of Brabant, probably Thomas’ most noteworthy opponent in this dispute, was accused of teaching that one thing could be true through reason, and that something contradictory could be true through faith. Therefore, Aristotle’s demonstration of the eternity of the world was “true philosophically” but not by revelation. Thomas thought this absurd.
Now, one such as Siger of Brabant might answer that something was philosophically ( i.e. naturally) true, yet, through a miracle of God, its contrary was actually true, and thus no real contradiction existed. Still, this would make God’s creation incomprehensible, and is contrary to the nature of God Himself, according to St. Thomas.
Let us return for the moment to the question hinted above, that of the eternity of the world. Thomas also separated himself, for example, from St. Bonaventure, by saying that the eternity of the world could not be proven or disproven, but rather, reason could not come to a definitive conclusion on the subject. However, faith’s role here taught us a truth we could not know by reason, that is, the creation of the world (even ” creation,” said Thomas, did not contradict, philosophically, an eternally existing world, which we shall examine below). But besides this, revelation therefore could help reason, in that it could show us where our reasoning may have gone astray and allow us to search for our errors. Therefore, the “fullness of the faith” can aid reason without becoming part of its demonstration, thereby leaving philosophy still to itself, and not confusing the two (faith and reason) all the while maintaining that the same God who gave us the “book of creation” likewise gave us the “book of Revelation” and that the two could never contradict one another, because they both spoke of one truth, the eternal Truth.
The church had made use of much of Aristotle’s logical works for centuries, but discounted much of the rest of his teaching as dangerous to orthodoxy. Eventually, “pagan” institutes of learning, such as at Alexandria, were closed. However, the Islamic world continued the study of Aristotle and Plato, highly commented upon by the neoplatonists, and sought to reconcile it with faith in one god who was not only prime mover, but who created the world. By the time of Thomas career, much of the “Aristotle” known to the Latins came with commentaries by Islamic philosophers. Often, their views of Aristotle conflicted with the Christian faith (and often with orthodox Islamic thought as well).
Thomas, therefore, had two issues to work out with Aristotle’s thought. The first one was to show that the Arab philosophers did not have a monopoly on what Aristotle actually meant. In fact, late in his short life, Thomas took the time to write extensive commentaries on many of Aristotle’s works, and even secular philosophers to this day generally regard them as faithful commentaries of the texts themselves.
There was perhaps no greater debate on reconciling Aristotle’s thought with Christianity than that of the Arabic interpretations of de Anima, especially as it relates to the immortality of individual persons. The overriding topic was that of the interpretation that Aristotle taught that that was one intellect in all men. In his Quastiones Disputatae de Anima (This work alone comprises about 150 typed pages, showing the emphasis Thomas placed on this dispute), Thomas responds to the question of Whether there is one possible intellect, or intellective soul, for all men:
“…if the possible intellect is a substance having existence separate from the body, it must be unique; because those things which have existence apart from a body can in no way have a multiple existence as a result of a multiplicity of bodies. However, the unicity of the intellect must be given special consideration because it involves a peculiar difficulty. For it is at once apparent that there cannot be one [possible] intellect for all men. It is, indeed, clear that the possible intellect is related to the perfections, which sciences are, as a primary perfection to a secondary one, and that we have scientific knowledge potentially because of a possible intellect. This fact compels us to maintain that a possible intellect exists. Moreover, it is obvious that not all men possess the same scientific knowledge, because some know sciences which others do not. Now it is evidently incongruous and impossible for one and the same primary subject to be in act and in potency with regard to the same form. For example, [it is impossible that] a surface be at, the same time, potentially and actually white. (Quastiones Disputatae de Anima, Article 3)
We see here that Thomas does not deny reason’s place in understanding the truth of things, but takes pains to demonstrate the conformity of reason, properly applied, and the truths revealed in revelation. He did not, for the most part, deny that Aristotle taught the truth, but rather, showed that his Arabic interpreters did not always come to the correct conclusions.
However, St. Thomas was not an “Aristotelian” in the proper sense. Where Aristotle was wrong, Thomas was clear in saying so, and he would take the time to show where Aristotle was in error. Again, the revelation of God was the final authority on truth. However, we must remember that the same Author of Truth has “written” both creation and revelation.
We again return to our example of the eternity of the world. Where some would use Aristotle’s arguments as definitive, others would try to show the errors in his “proofs” of the world’s eternity. Thomas approach differed from both of these.
There are certain truths that cannot be known by reason. For Thomas, the creation in time of the world was one such truth. Only through revelation could we know for certain that the world had a beginning in time. The task of the philosopher or theologian in this case was not to prove, by reason, that the world had a beginning, but rather, to demonstrate that arguments to the contrary were not demonstrations of fact.
We will take this opportunity to see how Thomas examines philosophical questions in light of the faith. He begins his work On the Eternity of the World:
“Let us assume, in accordance with the Catholic faith, that the world had a beginning in time. The question still arises whether the world could have always existed, and to explain the truth of this matter, we should first distinguish where we agree with our opponents from where we disagree with them.” (de Aeternitate Mundi)
Thomas, in looking at this problem, states the following:
We thus ought to determine whether there is any contradiction between these two ideas, namely, to be made by God and to have always existed. And, whatever may be the truth of this matter, it will not be heretical to say that God can make something created by him to have always existed. (de Aeternitate Mundi)
Here, Thomas is not concerned to show that the world was or was not created in time, but to see if the eternity of the world, as searched by reason alone, was contradictory in and of itself. Later, he states the following conclusion:
Therefore, there is no contradiction if we suppose that a cause instantaneously producing an effect does not precede its effect in time. A contradiction does obtain if the cause involved is one that produces its effects through motion, for the beginning of the motion precedes in time the end of the motion. Since people are accustomed to considering the type of cause that produces effects through motion, they do not easily grasp that an agent cause may fail to precede its effect in time, and so, having limited experience, they easily make a false generalization….
Therefore, at any instant at which God exists, so too can his effects, and thus God need not precede his effects in time. (de Aeternitate Mundi)
Here, St. Thomas shows us that there is no logical contradiction of a creating god and an eternal world. His argument is not to prove that the world is in fact eternal, but merely to show that God as creator and an eternal world are not mutually exclusive concepts. After this, Thomas examines another possible problem:
It remains to be seen, then, whether there is a contradiction in saying that something made has always existed, on the grounds that it may be necessary that its non-being precede it in time, for we say that it is made out of nothing. (de Aeternitate Mundi)
Thomas answers using a quote of St. Anselm’s:
“The third sense in which we can say that something is made out of nothing is this: we understand that something is made, but that there is not something from which it is made. In a similar way, we say that someone who is sad without reason is sad about nothing. We can thus say that all things, except the Supreme Being, are made by him out of nothing in the sense that they are not made out of anything, and no absurdity results.” On this understanding of the phrase “out of nothing,” therefore, no temporal priority of non-being to being is posited, as there would be if there were first nothing and then later something. (de Aeternitate Mundi)
St. Thomas Aquinas’ intellectual honesty shines forth in examples such as this. You see a man who lets the arguments take him wherever they lead. Because of his great faith in revelation, he need not fear reason, even when it cannot prove the tenants of his faith.