By Dr. Ronald P. McArthur
founding president of Thomas Aquinas College

Dr. Ronald P. McArthur
Dr. Ronald P. McArthur

The dialogues of Plato contain so much about so many things that our difficulties mount when we try to find with exactitude the whole intent of any one of them. Many of them show, however, and some in a manner which forces itself upon us, the importance of appetite in what looks at first to be the sphere of disinterested intelligence. Callicles, Gorgias, and Protagoras, to take but a few prominent examples, show us that desire can play such a large role in the intellectual life that it is hard to disentangle the desire that reality be as we want it to be from what we can hold with evidence about that same reality. Socrates may be ironic, or simply playful, when he says, after a lifetime of intellectual activity, that he knows nothing. His statement nevertheless suggests a salutary truth: wisdom is so very difficult to achieve that only a very few are, finally, wise. While we may rejoice as Socrates dismantles the arguments of some of his opponents, and be delighted as they are forced to take ridiculous positions in upholding their initial assertions, that rejoicing should be momentary. Who among us would, upon reflection, see himself as so freed from the constraints of his own desires, that he is able to see with perfect equanimity the reality about which he holds so many opinions?

There are many reasons which explain why wisdom seems to be reserved for the few, and we all know some of the most obvious; there are a relatively few who have the opportunity to give themselves to the life of study; few who study with persevering effort the very difficult subjects they should learn; few who pray with constancy for Divine help; few who attain the moral purity so conducive to the life of wisdom — that life which Aristotle without Revelation thought more divine than human. There is, however, another reason. It is usually overlooked because we tend to minimize its importance. It is this reason I wish now to bring to your attention.

St. Thomas (Ia IIae, Q. 58, a 1) distinguishes two meanings of the Latin word Mos:

Sometimes it means custom, in which sense we read (Acts 15:1): “Except you be circumcised after the manner (morem) of Moses, you cannot be saved.” Sometimes it means a natural or quasi-natural inclination to do some particular action, in which sense the word is applied to dumb animals. Thus we read (2 Macc. 1:2) that “rushing violently upon the enemy, in the manner of lions (Leonum more), they slew them”: and the word is used in the same sense (Ps. 67:7) when we read: “Who makes man in one manner (moris) to dwell in a house.”

When we use the word “mores” in English we mean, as the dictionary (The Concise Oxford) says, “Customs or conventions regarded as essential to or characteristic of a community.” And the dictionary then informs us that the word is the plural of the Latin word mos, custom. So far, St. Thomas and the English dictionary agree, but the second meaning of the word, found as well in the Latin dictionary, is worth our attention. While mos, as custom, may be best known to us, St. Thomas yet shows us the connection of the two meanings by showing how the second meaning, “a natural or quasi-natural inclination to do some particular action...”, is closely connected to the first. For, as St. Thomas says, “…the other meaning of mos, i.e. custom, is akin to [a natural or quasi-natural inclination], because custom becomes a second nature, and produces an inclination similar to a natural one.”

Our habits, whether good or evil, become like nature; they are “quasi-natural inclinations.” Custom, in its turn, plays its role in engendering those inclinations. It is because of the importance of custom that Plato would educate the young by accustoming them to only the right music, art, and literature. It is because of the crucial role our habits play that Aristotle claims that only those who are well brought up, and whose acquired inclinations tend towards the good, can study ethics with any profit.

It is relatively easy to see the role of custom in the moral life. Our manner of acting, as adults, and the general culture which surrounds us, have an almost decisive influence on the young, and incorporate them into a way of life. The family is a clear case; its absence even clearer. The same, however, is true in the more restricted life we call intellectual. And if we ask what custom does in this case we can answer: It presents to the intellect, by means of various doctrines and opinions, certain ways of thinking about things, and by so doing proportions the intellect to those very things. There are an infinity of examples, but let a few suffice for our purpose: 1) We are accustomed to the view that all social life should be understood in terms of rights, and hence this is the way we think about politics or society, almost to the exclusion of anything else; 2) we are likewise accustomed to calling the things we desire our values, and so, again, our political thought is laced together with talk about values; 3) almost all college students are moral relativists, a view they pick up in their culture; 4) almost all incoming college freshmen will tell you that lines are made up of points, a commonplace they have received from their teachers.

By constantly hearing something said over and over, the intelligence tends to accept it as true, whether or not it is true, and the will inclines towards what it hears. Custom, generally, leads us to judge by what we are used to hearing, are in the habit of hearing. This, again, is true not only in practical matters, but as well in the life of the intellect when it considers things speculatively.

Aristotle gives eloquent witness ( II Meta., c. 3):

The way we receive a lecture depends on our custom; for we expect a lecturer to use the language we are accustomed to, and any other language appears not agreeable but rather unknown and strange because we are not accustomed to it; for the customary is more known. The power of custom is clearly seen in the laws, in which the mythical and childish beliefs prevail over our knowledge of them, because of custom. Some people do not accept statements unless they are expressed mathematically; others unless they are expressed by way of examples; and there are some who demand that a poet be quoted as witness. Again, some demand accuracy in everything, while others are annoyed by it, either because they are not able to follow connections or because they regard it as petty.

Maimonides, in The Guide of the Perplexed (I,51), gives his own witness to the close tie between custom and habit:

... man has in his nature a love of, and an inclination for, that to which he is habituated. Thus you can see that the people of the desert — not withstanding the disorderliness of their life, the lack of pleasures, and the scarcity of food — dislike the towns, do not hanker after their pleasures, and prefer the bad circumstances to which they are accustomed to good ones to which they are not accustomed. Their souls accordingly would find no repose in living in palaces, in wearing silk clothes, and in the enjoyment of baths, ointments, and perfumes. In a similar way, man has love for, and the wish to defend, opinions to which he is habituated and in which he has been brought up and has a feeling of repulsion for opinions other than those. For this reason also man is blind to the apprehension of the true realities and inclines toward the things to which he is habituated.

Montaigne, in his essay on custom (I, 23), reaffirms the same power of custom and the intellectual habits it inculcates:

...the principal effect of the power of custom is to seize and ensnare us in such a way that it is hardly within our power to get ourselves back out of its grip and return into ourselves to reflect and reason about its ordinances. In truth, because we drink them with our milk from birth, and because the face of the world presents itself in this aspect to our first view, it seems that we are born on condition of following this course. And the common notions that we find in credit around us and infused into our soul by our father’s seed, these seem to be the universal and natural ones. Whence it comes to pass that what is off the hinges of custom people believe to be off the hinges of reason; …

St. Augustine, with his own account of his meeting and acquaintance with St. Ambrose, gives us a luminous example of the role of custom in the life of the intelligence. Trained in Rhetoric and a teacher of it, and, by the time he came to Milan, skeptical because of his disappointment with the Manicheans, Augustine heard Ambrose preach. Here is his account:

I attended carefully when he preached to the people, not with the right intention, but only to judge whether his eloquence was equal to his fame or whether it flowed higher or lower than had been told me. His words I listened to with the greatest care: his matter I held quite unworthy of attention. I enjoyed the charm of his speaking, though for all his learning it was not as pleasing or captivating as that of Faustus … Thus I did not take great heed to learn what he was saying but only to hear how he said it … (Confessions, V, cc. 14-15; emphases mine.)

Even in the case of a singularly endowed mind, and the mind of one who, for all his sins and corruptions, had by his own assessment diligently sought the truth, there was no escaping the power of the custom which had formed his intellect, a rhetorical formation which is evident in all his writings. Hence he was concerned not so much with the truth in hearing St. Ambrose, but with the mode of expression, and that according to his own predilections.

Long before his acquaintance with St. Ambrose however, Augustine, as he so recognized, had already been influenced by custom. He tells us that Cicero’s Hortensius, which contained an exhortation to philosophy, had changed the direction of his mind.

The book excited and inflamed me; in my ardor the only thing I found lacking was that the name of Christ was not there. For with my mother’s milk my infant heart had drunk in, and still held deep down in it, that name according to your mercy, O lord, the name of Your Son, my Savior, and whatever lacked that name, no matter how learned and excellently written, could not win me wholly. (Confessions, III, c. 4; emphases mine.)

When, however, he started to study the Scriptures, “... they seemed to me,” he says, “unworthy to be compared with the majesty of Cicero,” an author who wrote in the style to which he was accustomed. (Ibid. c. 5)

The proper words to describe our assent or dissent in relation to a given intellectual discourse will most likely be “I like what I hear, it is what I’m used to hearing,” and “I do not like what I hear, I’m not used to hearing it.” Such is the case when we base our acceptance or rejection not upon evidence and the ability to consider reasonably what we hear, but upon our appetite, which moves us to respond as we do.

We can, I think, clarify and give substance to the role of appetite in the intellectual life if we pay attention to some distinctions we learn from St. Thomas. He teaches us (Ia, Q. 82, a. 4) that the intellect moves the will in the species of final cause — nothing is desired unless it is presented by the intellect and seems good — while the will moves the intellect in the species of agent cause, for the will is the moving cause of all the powers of the soul except the vegetative.

This latter dependency, of the intellect upon the will, applied more properly to the speculative intellect, leads, as St. Thomas shows, to a further distinction (De Virtutibus In Communi, a. 7). There is a twofold dependence of the activity of the speculative intellect upon the will. Thinking is, first of all, natural, and seems good to the will; and so the intellect thinks, and in thinking can sometimes come to know. In this case the thinking depends upon the will, but not the knowledge, for it comes from the evidence of the object; it is the object which determines the intellect once thinking to think as it does.

There is another case, however, when the intellect presents an object which, without evidence, seems good to hold. Here, not only does the thinking itself depend upon the will, but what the intellect thinks as well. The determination of the intellect to its object comes in this case from the will itself.

We can make, again with St. Thomas, some further clarifications (De Veritate, Q. 14, a. 1). Our intellect is in potency to all intelligible forms, as is prime matter to all sensible forms. It is not in the beginning more determined one way than another. Anything which is indeterminate in this way is brought to a determination. The possible intellect must therefore be moved, and it will be so moved, granted the first movement of thinking, either by the object it thinks about or by the will. When, faced with an object, it is not more disposed to accept one part of a contradiction rather than another, the intellect will be in a state of doubt. When it adheres more to one part of a contradiction than to another, with fear that the other might be true, there will be opinion. When the intellect is determined to one part of a contradiction without fear that the other might be true, there will be understanding, through immediate evidence, or science, if of a conclusion depending finally upon immediate evidence.

When, however, the will moves the intellect to accept something determinately, not because it apprehends it as knower, but solely because it seems good, there will be faith.

In this situation [says St. Thomas] our understanding is determined by the will, which chooses to assent to one side [of a contradiction] definitely and precisely because of something which is enough to move the will, though not enough to convince the understanding — namely since it seems good or fitting to assent to this side. And this is the state of one who believes what another says because it seems fitting or useful to do so.

The object of faith is not manifest, and the will does not add to the object as true. The intellect adheres to the object because it seems good to the will. The intellect in this case is held captive by the will.

When the intellect is moved by the will to posit an act of human faith it is never certain of attaining the truth. All the intellect has are signs, which are many times precarious. Such signs in the intellectual life are a) the reputation of a teacher, b) when what he says is a reaffirmation of what one has heard before, c) when what he says fits with an antecedent disposition.

We cannot avoid the role of human faith in the intellectual life because when we begin to think, the intellect is not capable of judging what is proposed. We are, as it were, born into the intellectual life, and before the intellect can reasonably assent to anything, it has heard all sorts of opinions and untethered statements, and it is moved to judge according to what it has heard before, rejecting what seems strange to it. The will, to repeat, moves the intellect to represent to itself as a good (for the truth is a good) that which it has heard in its milieu. This is a determination of the intellect before the intellect poses a genuine act of knowledge. The intellect is determined by the fluctuations of the milieu in which it has participated; they impose a determination with which the intellect comes into the intellectual life.

There is then anIntellectual Mos, in both senses of the word with which we began: A natural or quasi-natural inclination of the intellect, of which the will is the principle, in dependence upon the time and custom within which it exists.


Man, by nature a social and political animal, is not meant to live alone. He needs others, whom he uses as if they were himself. This is easily seen in any society, where among other dependencies, he takes, because of his ignorance, what others say as if what is said were known to him. Without a trust in the words of others, human society would be impossible, and it is for this reason that Cicero teaches that truthfulness is a part of justice (De Officiis, I, 7), a doctrine with which St. Thomas agrees (IIa IIae, Q. 109, a. 3). There are good customs; without them we would be “the worst of animals.” There are also bad customs, and we would rid ourselves of them if we could; the only way, however, would be by substitution, for it is impossible to live without some custom.

Because the human intellect is weak, and because the pure life of intelligence is, properly, a divine life, there is a necessity of first believing before we can acquire knowledge or even good opinion. St. Thomas gives witness by reflecting upon the order of disciplines in relation to our order of knowing. While Metaphysics is the highest natural wisdom, which considers being as being and the first principle of being, and while it confirms and defends the other disciplines, it is yet learned last. Along the way, however, the learner will accept on faith that the order of learning, and the things he learns will lead, finally, to the apprehension of God as the first principle of all reality. He will also believe some truths from outside the first disciplines he learns, which only later will he understand. He will not be able to defend even the first principles of the disciplines he learns until he studies Metaphysics, which defends itself and all the other disciplines

The unwillingness to submit to intellectual masters condemns the intellect to wander aimlessly and without profit, a wandering which seems nevertheless to bespeak an autonomy freed from the slavery of a mindless repetition of old and irrelevant doctrines hardened into dogmas. The autonomy is an illusion. Gilson has well shown, for example, how Descartes, in attempting to re-think the whole philosophical enterprise, to free himself from every influence, yet uses scholastic terms and expressions, even though transformed, which he no doubt received from his Catholic teachers. When, therefore, Rousseau, in his Discourse on the Sciences and Arts, admits finally that some few thinkers might be necessary for the well being of mankind, he yet restricts severely their number to those “Whom nature destined to be her disciples”, who “need[ed] no teachers”:

Verulam [Bacon], Descartes, Newton, these preceptors of the human race had none themselves; indeed, what guides would have led them as far as their vast genius carried them? Ordinary teachers would only have restricted their understanding by confining it within the narrow capacity of their own. The first obstacles taught them to exert themselves, and they did their utmost to traverse the immense space they covered. If a few men must be allowed to devote themselves to the study of the sciences and arts, it must be only those who feel the strength to walk alone in their footsteps and go beyond them.

While there might be some truth in Rousseau’s position, it is fair to note that Euclid’s Elements played an immense role in Newton’s Principia and Descartes’ Geometrie, and that Bacon would have been hard pressed to write about his idols without the benefit of previous thinkers, or to determine clearly his method without comparing it to a version of the Aristotelian tradition he hoped to displace. And all were probably taught to read and write, and thought and wrote using the customary grammar of their languages. No one escapes the effect of intellectual custom, no matter how far he extends the province of learning, or how much he opposes his predecessors. (This is the inescapable truth which leads some to the conclusion that no doctrine can even be understood without knowing the times in which it is written, itself a doctrine which makes liberal education impossible.) “We stand,” says St. Bernard, “on the shoulders of giants,” whose doctrines were no doubt understood only after having been believed to be worthy of a most serious attention.

St. Augustine saw clearly the universal importance of custom in the intellectual life. He teaches that there is a natural order of learning. He asks, in De Moribus Ecclesiae (c. 2), where, in his argument with the Manichees, he should begin:

Where, then, shall I begin? With authority, or with reasoning? In the order of nature, when we learn anything, authority precedes reasoning. For a reason may seem weak, when, after it is given, it requires authority to confirm it. But because the minds of men are obscured by familiarity with darkness, which covers them in the night of sins and evil habits, and cannot perceive in a way suitable to the clearness and purity of reason, there is a most wholesome provision for bringing the dazzled eye into the light of truth under the congenial shade of authority. But since we have to do with people who are perverse in all their thoughts and words and actions, and who insist on nothing more than a beginning with argument, I will, as a concession to them, take what I think the wrong method in discussion. (Emphases mine.)

Augustine uses this same doctrine in his sermons and letters:

If you cannot understand, believe in order that you may understand. (Sermo CXVIII)

What soul hungering for eternity and shocked by the shortness of this present life would resist the splendor and the majesty of the authority of God? (Epistle CXXXVII)

While Augustine is in his sermons and epistles speaking about the supernatural truth and God’s own authority, what he ways about the beginning of intellectual assent is true, as he says, about the whole life of the intellect, especially in the case of fallen man. Newman is further witness. He says (Apologia, c.5):

I have no intention at all of denying that truth is the real object of our reason, and that, if it does not attain the truth, either the premise or the process is in fault; but I am not speaking of right reason, but reason as it acts in fact and concretely in fallen man and that its tendency is towards a simple unbelief in matters of religion.

He also speaks of the efforts “to withstand and baffle the fierce energy of passion and the all-corroding, all-dissolving skepticism of the intellect in religious inquiries.”

If the intellectual custom which surrounds us is good, the intellect has a chance to become directed towards the truth, a chance to lead a properly intellectual life. If however the custom is bad, the intellect will be misdirected from the beginning, and its chance of following the right path is close to non-existent.

As in all things human, much of intellectual custom is not helpful, and some of it destructive. Here is a statement by Eric Voeglin in The New Science of Politics which, written years ago, gives us a sense of the custom which surrounds us:

We live in the world of the dialogue, where the recognition of the structure of reality, the cultivation of the virtues of sophia and prudentia, the discipline of the intellect and the development of theoretical culture and the life of spirit are stigmatized in public as reactionary, while disregard for the structure of reality, ignorance of facts, fallacious misconstruction and falsification of history, irresponsible opining on the basis of sincere conviction, philosophical illiteracy, spiritual dullness, and agnostic sophistication are considered the virtues of man, and their possession opens the road to public success.

Since custom induces a second nature, the case of the corrupted intellect is all but hopeless. The intellect, once directed against the truth, can, by natural means, hardly ever be salvaged. This need not be because of a closed mind, or bad morals, though they play their part, but because of custom itself, which incapacitates the intellect for the arduous task of pursuing wisdom. All this, the result of our fallen nature, makes a great part of the intellectual life for most of us a matter of appetite. Socrates is surely our friend when he so instructs us in the Dialogues.

Since we cannot escape intellectual custom, and since most intellectual customs are at the very least deficient, we are indeed in a precarious position with regard to the intellectual life … and there seems to be no way through our difficulties. (The attempt to doubt everything, so fashionable in our times, is no solution, for then the intellectual life could never begin.)


St. Paul admonishes Timothy, a bishop he himself had consecrated, to “preach the word, be urgent in season and out of season, convince, rebuke, and exhort, be unfailing in patience and in teaching.” ( II Timothy, 4, 2) He admonishes Titus, another bishop, that the bishop “ … must hold firm to the sure word as taught, so that he may be able to give instruction to those who contradict it.” (Titus, 1, 9) It is most important, in every case, as St. Paul charges Timothy, to “guard the truth that has been entrusted to you by the Holy Spirit who dwells within us.” ( II Timothy, 1, 14)

The Church has, as part of its mission, the duty to teach, explain, conserve, and defend the Revelation which has been entrusted to it in Scripture and Tradition. Because we to whom that Revelation is offered could never arrive, by reason alone, at the most important truths it teaches, because it is supereminently truthful, and because it does not attempt to defend its truths, it should not be surprising that the content of Divine teaching has been so often the subject of dispute, and that it has been obscured, distorted, and even denied by those who claim to believe it. It must be clarified, “in season and out of season,” if it is to be conserved, and the errors which would destroy it must be from time to time be exposed and anathematized. So difficult is it to understand what exactly God is teaching through His Revelation, so prone is the human intellect to fashion fables in the place if it, so easy is it to misunderstand with the best of faith, and so contrary to it are the customs of the world, that St. Augustine was prompted to say that heresies are good for the Church because they lead to fruitful clarifications, without which the teachings of the Faith would most probably become more vague with the passage of time.

The Church teaches us in many ways — through Councils, Definitions, Encyclicals, Apostolic Exhortations and so on. More to our point, her doctrine is further clarified, developed and defended by Sacred Theology. Since, however, theology is the work of human reason, even though illumined by faith, and is as such fallible, the Church, in fulfilling her mission, judges theological doctrines, and guides us here as elsewhere. This very guidance is, in fact, based, as are all the prerogatives of the Magisterium, upon the promises of Christ that the Church would never fail in proclaiming the truth, and in helping us to adhere to it.

In so judging theological doctrines, the Church establishes an intellectual custom which is opposed to the fluctuations, weaknesses, and perversities of human custom; it is based upon God’s word and the inspiration of the Holy Spirit, and it can never deceive.

In following the teaching of the Church here as elsewhere we are more certain of being in the path of truth than we are of any purely human truth we can ever hold. Remember, in this connection, that what we hold by human faith is less certain than opinion or science, and unsatisfactory so far as the intellect is concerned. It is greatly different with supernatural faith. Though the intellect, as such, is not satisfied even when we hold something by Divine faith, we are, because we rest on God’s own intellect, and because we are moved by Him to accept His teaching, more certain here than we are in holding anything by reason alone.

What then, does the Church, to whom He has entrusted His concerns for us, teach concerning theological doctrines?

1. Pope John XXII, speaking about St. Thomas, said before his canonization that “his life was saintly and his doctrine could only be miraculous … because he enlightened the church more than all the other doctors. By the use of his works a man could profit more in one year than if he studies the doctrine of others for his whole life.”

2. St. Pius V declared him a Doctor of The Church, saying he was “the most brilliant light of the Church,” whose works are “the most certain rule of Christian doctrine by which he enlightened the Apostolic Church in answering conclusively numberless errors … which illumination has often been evident in the past and recently stood forth prominently in the decrees of the Council of Trent.”

3. Benedict XIII wrote to the Order of Preachers that they should “pursue with energy your Doctor’s works, more brilliant than the sun and written without the shadow of error. These works made the Church illustrious with wonderful erudition, since they march ahead and proceed with unimpeded step, protecting and vindicating by the surest rule of Christian doctrine, the truth of our holy religion.”

4. Leo XIII stated that “this is the greatest glory of Thomas, altogether his own and shared with no other Catholic Doctor, that the Fathers of Trent, in order to proceed in an orderly fashion during the conclave, desired to have opened upon the altar together with the Scriptures and the decrees of the Supreme Pontiffs, the Summa of St. Thomas Aquinas whence they could draw counsel, reasons and answers.”

Again from Leo XIII: “This point is vital, that Bishops expend every effort to see that young men destined to be the hope of the Church should be imbued with the holy and heavenly doctrine of the Angelic Doctor. In those places where young men have devoted themselves to the patronage and doctrine of St. Thomas, true wisdom will flourish, drawn as it is from solid principles and explained by reason in an orderly fashion … Theology proceeding correctly and well according to the plan and method of Aquinas is in accordance with our command. Every day We become more clearly aware how powerfully Sacred Doctrine taught by its master and patron, Thomas, affords the greatest possible utility for both clergy and laity.

5. St. Pius X said that the chief of Leo’s achievements is his restoration of the doctrine of St. Thomas. For he “restored the Angelic Doctor … as the leader and master of theology, whose divine genius fashioned weapons marvelously suited to protect the truth and destroy the many errors of the times. Indeed those principles of wisdom, useful for all time, which the holy Doctors passed on to us, have been organized by no one more aptly than by Thomas, and no one has explained them more clearly.” Indeed, Pius said, those who depart from the teaching of St. Thomas “seem to effect ultimately their withdrawal from the Church … As we have said, one may not desert Aquinas, especially in philosophy and theology, without great harm; following him is the safest way to the knowledge of divine things.… If the doctrine of any other author or saint has ever been approved at any time by us or our predecessors with singular commendation joined with an invitation and order to propagate and to defend it, it may be easily understood that it was commended only insofar as it agreed with the principles of Aquinas or was in no way opposed to them.” Theology professors “should also take particular care that their students develop a deep affection for the Summa … In this way and no other will theology be restored to its pristine dignity, and the proper order and value will be restored to all sacred studies, and the province of the intellect and reason flower again in a second spring.”

6. Benedict XV stated that “the eminent commendations of Thomas Aquinas by the Holy See no longer permit a Catholic to doubt that he was divinely raised up that the Church might have a master whose doctrine should be followed in a special way at all times.”

7. Pius XI said that “indeed, We so approve of the tributes paid to his almost divine brilliance that we believe Thomas should be called not only Angelic but Common or Universal Doctor of the Church. As innumerable documents of every kind attest, the Church has adopted his doctrine for her own.… It is no wonder that the Church has made this light her own and has adorned herself with it, and has illustrated her immortal doctrine with it … It is no wonder that all the popes have vied with one another in exalting him, proposing him, inculcating him, as a model, master, doctor, patron and protector of all schools … Just as it was said of old to the Egyptians in time of famine: ‘Go to Joseph, so that they should receive a supply of corn to nourish their bodies, so to those who are now in quest of truth We now say: ‘Go to Thomas’ that they may ask from him the food of solid doctrine of which he has an abundance to nourish their souls unto eternal life.”

Since Sacred Theology uses philosophy as a handmaid, the Church’s duty does not end with a judgment upon Theology alone, but extends to philosophy as well.

1. Pius XII said that “… the Angelic Doctor interpreted [Aristotle] in a uniquely brilliant manner. He made that philosophy Christian when he purged it of the errors into which a pagan writer would easily fall; he used those very errors in his exposition and vindication of Catholic truth. Among the important advances which the Church owes to the great Aquinas this certainly should be included that so nicely did he harmonize Christian truth with the enduring peripatetic philosophy that he made Aristotle cease to be an adversary and become, instead, a militant supporter for Christ … Therefore, those who wish to be true philosophers … should take the principles and foundations of their doctrine from Thomas Aquinas. To follow his leadership is praiseworthy: on the contrary, to depart foolishly and rashly from the wisdom of the angelic Doctor is something far from Our mind and fraught with peril … For those who apply themselves to the teaching and study of Theology and Philosophy should consider it their capital duty, having set aside the findings of a fruitless philosophy, to follow St. Thomas Aquinas and to cherish him as their master and their leader.”

2. St. Pius X said that “all who teach philosophy in Catholic schools throughout the world should take care never to depart from the path and method of Aquinas, and to insist upon that procedure more vigorously every day...We warn teachers to keep this religiously in mind, especially in metaphysics, that to disregard Aquinas cannot be done without suffering great harm.”

3. Benedict XV said that “along with our predecessors We are equally persuaded that the only philosophy worth our efforts is that which is according to Christ. Therefore the study of philosophy according to the principles and system of Aquinas must certainly be encouraged so that the explanation and invincible defense of divinely revealed truth may be as full as human reason can make of it.”

These are but a few of the testimonies of the Popes throughout the centuries after the death of St. Thomas, and I could have added the testimony of John Paul II, but that would have entailed repeating almost wholly two separate addresses, one on the Philosophy of Thomas Aquinas to the Angelicum University, the other to the Eighth International Thomistic Congress, wherein the Holy Father repeats for the most part the commendations of his predecessors concerning the doctrine, principles and method of St. Thomas, and emphasizes the importance of adhering to him today for the facing of modern problems both theological and philosophical.


It is, of course decisive for us to believe, to rest with confidence that we can never be deceived by the teaching Church. Since, however, the supernatural life is based upon the natural, and is never in opposition to it, since grace perfects nature, it would be strange if, believing and practicing our faith, we did not in the course of our lives experience in some sense a ring of truth the more we conform to the norms of the Magisterium. It would be strange, for instance, if, living according to the sexual morality of the Gospel we did not experience, amidst all the attendant difficulties, a sense of joy, a peace of conscience and the inner freedom which results from self-control. The same is true in the intellectual life; it would be strange if, in following the Church’s guidance, we did not experience a sense of accomplishment, a sense that we were progressing, a sense that we were, as we go on, more at one with the reality which is the object of our study.

Such is in fact the case with the study of St. Thomas

To have found a master in the intellectual life is as precious as it is rare; to have been directed to one by the Church is as fortunate as it is precious.

Those who knew him report that St. Thomas himself “no sooner heard [St. Albert] expound every science with such wondrous depth of wisdom, that he rejoiced exceedingly at having quickly found that which he had come to seek, one who offered him so unsparingly the fulfillment of his heart’s desire.” It is said further that, in order to profit from this exceptional opportunity, he “began to be more than ever silent, more than ever assiduous in study and devout in prayer” (James A. Weisheipl, O.P., Friar Thomas D’Aquino).

St. Thomas himself gives us an insight into the importance of a good teacher. He shows that something may be in potency in two ways. Air, to take an example, is in potency to be consumed by fire passively; if fire is to spread, fire itself will be the principle agent, extrinsic to the air it consumes. On the other hand, a living thing is in potency to health actively; if there is to be health the living thing itself is the principle agent, and any extrinsic agents, such as the doctor, are secondary agents helping the principle agent achieve its end.

The intellect is in potency to science, and its potency is active. Just as a living thing, becoming sick, can become healthy by nature or by the help of secondary agents, so the intellect can learn through discovery, or, most likely, with the help of a teacher. Where there is a teacher, the intellect of the learner is always the principle cause of learning; the teacher is never more than a secondary cause. Just as the doctor must follow the order of nature if he expects to heal, so the teacher must, says St. Thomas, follow the order the intellect would follow without him if it could. This means that the teacher must follow the order of discovery, the order which is natural to the intellect, if he is to teach. If he does not follow the order imposed by the object of study, he becomes a cause of the corruption of the learner’s mind, even though he says what is true.

This can be seen, says St. Thomas, by reflecting upon the means the human teacher must use as he teaches. Unlike God who can illumine the intellect from within, or an angel who can order the imagination from within, the human teacher uses words as signs, which are proposed to the learner from without. The order in the words of the teacher is a sign of the order of his concepts. The more orderly the words, the more orderly the concepts. The learner hears the words of the teacher, and they lead to images in his imagination; the more orderly are those words, the more orderly are the images; the more orderly the images the more orderly the concepts in his intellect, which are abstracted from the images.

So weak is the human intellect — unlike the body, which does not need the doctor for the most part — that, as St. Thomas says, the words of the teacher are more proportioned to the intellect than things themselves. Since we learn through the use of images, and words can bring about an ordering of those images, the great teacher, through the excellence of his words, orders well the images in our imagination, and through them our minds, with the result that we can be led to understand the realities signified by the words. The more we apply ourselves to the words, and hence the concepts of the master,the more will we grasp reality. And since, as learners, we are ignorant, and since truth is difficult to obtain, we must have faith enough in the teacher to stay with his words, through them to grasp his thought, and through that thought become one with the objects themselves. We can see from the very nature of teaching and learning, that without faith learning becomes almost impossible; no faith, no light!

St. Thomas proves to be the master who, without peer, can order our minds, so that we ordinary mortals can in our limited way come to see some of the truths we first accepted from him on faith, truths we would never have seen without that faith in the master.

It is then most important that here, as elsewhere, we obey the Church; if we do we shall experience some of what she teaches about St. Thomas, and we shall see for ourselves more about reality than ever we would had we studied without him.


Our Lord has not left us bereft of an intellectual custom. If we think according to it we will likely progress towards a greater and greater grasp of the truth, and we may if we persist become one of those relatively few who actually begin to live the intellectual life. If, on the other hand, we knowingly reject the guidance of the Church, we, Catholics who have been graced with so many gifts, will be worse than those who have never been given them, and who wander about without ever finding the right path. If we refuse to accept St. Thomas as our master, knowing full well what the Church has constantly taught concerning him, that rejection will most likely throw us back upon the weak and fallible customs of our own milieu; it could then be said of us that “it would have been better for them never to have known the way of righteousness than after knowing it to turn back from the holy commandment delivered to them. It has happened to them according to the true Proverb, The dog turns back to his own vomit, and the sow is washed only to wallow in the mire.” (2 Peter 2:21-22)