(Click here for the theses themselves.)

The Twenty-Four Fundamental Theses Of Official Catholic Philosophy

By P. Lumbreras, O.P., S.T.Lr., Ph.D.

Nobody can deny that the Church has full authority to regulate the teaching of philosophy in Catholic educational institutions. Pope Leo XIII said: "The only-begotten Son of the Eternal Father, who came on earth to bring salvation and the light of divine wisdom to men, conferred a great and wonderful blessing on the world when, about to ascend again into heaven, He commanded the Apostles to go and teach all nations, and left the Church which He had founded to be the common and supreme teacher of the peoples."1 And Pius X: "Let no sincere Catholic dare to doubt the truth of this statement of the Angelic Doctor: 'The regulation of studies belongs chiefly to the authority of the Apostolic See, by which the universal Church is governed, whose welfare is promoted by general study.'"2 The reason is obvious. For since there was given to the Church a certain number of truths spoken certainly by God, but to men and consequently in our human language, it is a duty on the part of the Church, not only to keep intact such a sacred deposit, but also to explain it as much as possible, and to defend it by means of human reason. The Church, therefore, has an absolute and exclusive right to pronounce judgment on the accordance of any system of philosophy with revealed dogma; to determine which of the various philosophical systems is more suitable for the right explanation of this dogma and offers the most solid basis for its safeguard and vindication. "The Apostle warns us," Leo XIII declares, "that the faithful of Christ are often deceived in mind 'by philosophy and vain deceit.' For this reason the supreme pastors of the Church have always held that it is part of their office to advance, with all their power, knowledge truly so called; but at the same time to watch with the greatest care that all human learning shall be imparted according to the rule of the Catholic faith. Especially is this true of philosophy, on which the right treatment of other sciences depends in great measure."3 Furthermore, since the professors in Catholic institutions receive from the Church their right to teach, and teach, consequently, in the name of the Church, the Church is evidently entitled to control their teaching, and to determine for them a line of doctrine to be followed in their teaching. It is Pius X, who addressing the professors of Christian philosophy and sacred theology reminds them that "they did not receive the faculty of teaching to communicate to their pupils their own opinions, but to impart to them the doctrines most approved by the Church."4

There arises then a true and strict obligation for all Catholic teachers, the day the Church fixes a body of philosophical doctrine to be taught by them. Catholic teachers must fulfill such an obligation, and must teach the doctrine the Church wants them to teach, and must teach it with that favor, that praise, that commendation which the Church demands.

It may be objected that this ecclesiastical interference might become an obstacle to further progress, or to any improvement in philosophical sciences. This is not true. If, as intelligent Catholics, we are sure of the divine assistance which guides the Church in all her doctrinal judgments, especially when this doctrinal judgment concerns the universal body of Catholic teachers, then it would seem that this very definite system should give us greater help and confidence in real advancement, since we know how to advance in the right way. Such a system would insure us against false progress, and ratify, assure and encourage true progress. It was in the use of such a power conferred upon the Church and in the accomplishment of his duty to teach the faithful, that Pope Leo XIII, on August 4, 1879, restored the scholastic philosophy. "If anyone look carefully," he says, "at the bitterness of our times, and if, further, he consider earnestly the cause of those things that are done in public and in private, he will discover with certainty the fruitful root of the evils which are now overwhelming us, and of the evils which we greatly fear. The cause he will find consists in this—evil teaching about things human and divine-- has come forth from the schools of philosophers; it has crept into all orders of the State; and it has been received with the common applause of very many. Now, it has been implanted in man by nature to follow reason as the guide of his actions, and, therefore, if the understanding goes wrong in anything, the will easily follows. Hence it comes about that wicked opinions in the understanding flow into human actions and make them bad."5 And afterwards: "Here and there a certain new kind of philosophy has taken the place of the old doctrine; and because of this, men have not gathered those desirable and wholesome fruits which the Church and civil society itself could have wished. The aggressive innovators of the sixteenth century have not hesitated to philosophize without any regard whatever to the Faith, asking, and conceding in return, the right to invent anything that they can think of, anything that they please. From this it quickly followed, of course, that systems of philosophy were multiplied beyond all reason, and that there sprang up conflicting and diverse opinions even about some of the chief things, which are within human knowledge. From a multiplicity of opinions men very often pass to uncertainty and doubt; while there is no one who does not see how easily their minds glide from doubt into error."6

Such a deplorable condition was not the exclusive lot of non-Catholic students of philosophy. For the same Pope adds: "But, since man is drawn by imitation, we have seen these novelties lay hold of the minds of some Catholic philosophers, who, undervaluing the inheritance of ancient wisdom, have chosen rather to invent new things than to extend and perfect the old by new truths, and that certainly with unwise counsel, and not without loss to science; for such a manifold kind of doctrine has only a shifting foundation, resting as it does on the authority and will of individual teachers. For this reason it does not make philosophy firm and strong and solid, like the old philosophy, but, on the contrary, makes it weak and shallow."7

As the only remedy, the Roman Pontiff desires the scholastic philosophy to be implanted everywhere. "The Doctors of the Middle Ages," he says, "whom we call scholastics, set themselves to do a work of very great magnitude. There are rich and fruitful crops of doctrine scattered everywhere in the mighty volumes of the holy Fathers. The aim of the scholastics was to gather these together diligently, and to store them up, as it were, in one place, for the use and convenience of those that come after."8 And, having quoted the authority of Sixtus V, who said that God had enriched and strengthened His Church by the founding of scholastic theology, whose study must always be of great assistance, "whether it be for the right understanding and interpretation of Scripture, or for reading and expounding the Fathers with greater safety and profit, or for laying bare and answering different errors and heresies," Leo XIII expresses himself in these terms: "Although these words seem to bear reference solely to scholastic theology, nevertheless they may plainly be accepted as equally true of philosophy and its praises. For the noble endowments which make the scholastic theology so formidable to the enemies of truth—to wit, as the same Pontiff adds, that ready and close coherence of cause and effect, that order and array as of a disciplined army in battle, those clear definitions and distinctions, by which light is distinguished from darkness, the true from the false, expose and strip naked, as it were, the falsehoods of heretics wrapped around by a cloud of subterfuges and fallacies —those noble and admirable endowments, We say, are only to be found in a right use of that philosophy which the scholastic teachers have been accustomed carefully and prudently to make use of even in theological disputations. Moreover, since it is the proper and special office of the scholastic theologians to bind together by the fastest chain human and divine science, surely the theology in which they excelled would not have gained such honor and commendation among men if they had made use of a lame and imperfect or vain philosophy."9

The warning of Pope Leo XIII was not sufficiently heeded. And years after, his successor, Pope Pius X, was obliged to condemn an error which had spread not only among the Church's open enemies, but among many who belonged to the Catholic laity, and, what is far more lamentable still, to the ranks of the priesthood itself, who lacked, as the Pope testifies, the firm protection of philosophy and theology. This error is known under the name of Modernism.

Now, one of the demands of the Modernists was the "reform of philosophy, especially in the seminaries: the scholastic philosophy is to be relegated to the history of philosophy among obsolete systems, and the young men are to be taught modern philosophy which alone is true and suited to the times in which we live."10

But Pius X, a man of our days, living in our own century, and conscious of present progress, not less than of present evils, condemned such a tendency, as a Modernistic one. And coming to the remedies to be applied to such a critical situation he says: "In the first place, with regard to studies, We will and ordain that scholastic philosophy be made the basis of the sacred sciences."11

Scholastic philosophy, however, is a very large name. For there were many who strove in the Middle Ages for the establishment of a rational philosophy in conformity with dogma and with a view of affording assistance to the theological studies. Since then we have had several systems of philosophy among the schoolmen. And each system has its opinions. And these opinions are never uniform, often contradictory.

When the Pope, therefore, decrees the teaching of Scholastic Philosophy, does he mean indifferently any of those systems of philosophy? Are all the scholastic teachings, in the mind of the Pope, on an equal basis in this regard?

Certainly not. For there is one schoolman specially mentioned in the pontifical documents; and there is a system of scholastic philosophy, which is individually praised, and praised with special recommendation by the Roman Pontiffs. "Far above all other scholastic Doctors," Leo XIII says, "towers Thomas Aquinas, their master and prince. Cajetan says truly of him: 'So great was his veneration for the ancient and sacred Doctors that he may be said to have gained a perfect understanding of them all.' Thomas gathered together their doctrines like the scattered limbs of a body, and moulded them into a whole. He arranged them in so wonderful an order, and increased them with such great additions, that rightly and deservedly he is reckoned a singular safeguard and glory of the Catholic Church. His intellect was docile and subtle; his memory was ready and tenacious; his life was most holy; and he loved the truth alone. Greatly enriched as he was with the science of God and the science of man, he is likened to the sun, for he warmed the whole earth with the fire of his holiness, and filled the whole earth with the splendor of his teaching. There is no part of philosophy, which he did not handle with acuteness and solidity. He wrote about the laws of reasoning; about God and incorporeal substances; about man and other things of sense; and about human acts and their principles. What is more, he wrote on these subjects in such a way that in him not one of the following perfections is wanting: a full selection of subjects; a beautiful arrangement of their divisions; the best method of treating them; certainty of principles; strength of argument; perspicuity and propriety in language; and the power of explaining deep mysteries. Beside these questions and the like, the Angelic Doctor, in his speculations, drew certain philosophical conclusions as to the reasons and principles of created things. These conclusions have the very widest reach, and contain, as it were, in their bosom the seeds of truths well-nigh infinite in number. These have to be unfolded with most abundant fruits in their own time by the teachers who come after him. As he used his method of philosophizing, not only in teaching the truth, but also in refuting error, he has vanquished all errors of ancient times; and still he supplies an armory of weapons, which brings us certain victory in the conflict with falsehoods ever springing up in the course of years. Moreover, carefully distinguishing reason from faith, as is right, and yet joining them together in a harmony of friendship, he so guarded the rights of each, and so watched over the dignity of each, that, as far as man is concerned, reason can now hardly rise higher than she rose, borne up in the flight of Thomas; and faith can hardly gain more and greater helps from reason than those which Thomas gave her."12 And again: "There is nothing which We have longer wished for and desired than that you (the Bishops), should give largely and abundantly to youths engaged in study the pure streams of wisdom which flow from the Angelic Doctor as from a perennial and copious spring."13

This same principality was granted to St. Thomas' philosophy by Pius X. "Let it be clearly understood above all things," he says, "that the scholastic philosophy We prescribe is chiefly that which the Angelic Doctor has bequeathed to us, and We, therefore, declare that all the ordinances of Our Predecessor on this subject continue fully in force, and, as far as may be necessary, We do decree anew, and confirm, and ordain that they be by all strictly observed. In seminaries where they may have been neglected let the Bishops impose them and require their observance, and let this apply also to the Superiors of religious institutions."14 And the Pope ends this paragraph with these precise words: "Further let professors remember that they cannot set St. Thomas aside, especially in metaphysical questions, without grave detriment"; words which come again a short time after with some little, but meaningful modification: "Let professors remember that they cannot set St. Thomas aside, however slightly, especially in metaphysical questions, without grave detriment."15

Still, St. Thomas' philosophy is not simply the chief one within the official Scholasticism, but it is the only one.

Leo XIII had expressed this before: "We, therefore, while We declare that everything wisely said should be received with willing and glad mind, as well as everything profitably discovered or thought out, exhort all of you, Venerable Brothers, with the greatest earnestness to restore the golden wisdom of St. Thomas, and to spread it as far as you can, for the safety and glory of the Catholic Faith, for the good of society, and for the increase of all the sciences. We say the wisdom of St. Thomas; for it is not by any means in our mind to set before this age, as a standard, those things which may have been inquired into by Scholastic Doctors with too great subtlety; or anything taught by them with too little consideration, not agreeing with the investigations of a later age; or lastly, anything that is not probable. Let, then, teachers carefully chosen by you do their best to instill the doctrine of Thomas Aquinas into the minds of their hearers; and let them clearly point out its solidity and excellence above all other teaching. Let this doctrine be the light of all places of learning, which you may have already opened, or may hereafter open. Let it be used for the refutation of errors that are gaining ground."16

But it was Pius X who gave the most express and conclusive interpretation: "Since We have said (in the Motu Proprio 'Sacrorum Antistitum') that Aquinas' philosophy was chiefly to be followed, and We did not say solely, some thought to comply with, or at least not to oppose Our will in taking the philosophy of any of the Scholastic Doctors indiscriminately, even when such a philosophy was in repugnance to the principles of St. Thomas. But these their mind has greatly deceived. It is quite evident that when We set St. Thomas up as the leader of scholastic philosophy, We have wished this to be understood especially of his principles, upon which such a philosophy is established. Because as we must reject that old opinion which held as irrelevant for the faith what anyone thinks about creatures, if he thinks rightly about God—since an error on the nature of creatures originates false knowledge of God—so we must keep reverently and inviolately St. Thomas' principles on philosophy, from which flows such a doctrine on creatures as is in harmony with faith; by which all errors of all ages are refuted; by which we are made aware of those attributes which must be given to God and to nothing else but Himself; and by which both the diversity and the analogy between God and creatures is skillfully illustrated... Neither sane reason will neglect, nor religion will allow that such a wonderful richness of science—which he received from his predecessors and with his almost angelic genius he himself ameliorated, increased and used to prepare, illustrate and defend the sacred doctrine for human minds—suffer any loss. Particularly, for if the Catholic truth be destitute of this valuable help, in vain would anyone seek help from that philosophy whose principles are common with, or not opposed to Materialism, Monism, Pantheism, Socialism and Modernism... Consequently We have already instructed all teachers of philosophy and sacred theology that to deviate a single step from St. Thomas, especially in metaphysical questions, would not be without great detriment. Now furthermore We say that those who have perversely interpreted or absolutely despised the principles and chief propositions of St. Thomas' philosophy, those not only do not follow St. Thomas, but wander also widely from him."17 And the Pope, overcoming some objection which could be made from pontifical documents praising some other Doctor or philosopher, adds: "If We or any of Our Predecessors have ever approved the doctrine of some other author or saint, even as to recommend and ordain its divulgation and defense, it is easily understood that the same is to be approved, inasmuch as it is consonant with the principles of St. Thomas, or at least not opposed to them."18

Such a disposition of the Popes became finally a formal universal precept, since the promulgation of the Canon Law: "Religious who have already studied their humanities should devote themselves for two years at least to philosophy, and four years to theology, following the teaching of St. Thomas in accordance with the instructions of the Holy See."19 And "The study of philosophy and theology and the teaching of these sciences to their students must be accurately carried out by professors according to the arguments, doctrine, and principles of St. Thomas, which they are inviolately to hold."20

Nevertheless, St. Thomas did not write a textbook on philosophy, neither did he draw up a list of the fundamental principles of his philosophy.

Hence we have many philosophical books, which claim to reflect the mind of St. Thomas, though they contain opinions contrary to each other. We know of several scholastic doctors, who appropriate for themselves the title of Thomists and whose teaching is contradictory in many points. And we are aware that some of the doctrines, which by one school are supposed to be fundamental in the Thomistic Philosophy, are neglected and may be rejected by another school.

Pope Leo XIII had admonished on this subject: "But lest the false should be drunk instead of the true; or lest that which is unwholesome should be drunk instead of that which is pure; take care that the wisdom of Thomas be drawn from his own fountain, or at any rate from those streams which, in the certain and unanimous opinion of learned men, yet flow whole and untainted, inasmuch as they are fed from the fountain itself. Take care, moreover, that the minds of the young be kept from streams which are said to have flowed from thence, but in reality have been fed by unhealthy waters from other springs."21

Yet, such a distinction was anything but easy, on account of the traditional prejudices of every School.

Hence a further official declaration was necessary.

The Congregation of Studies published on July 27, 1914, a document whose title is as follows: "Certain theses, contained in the doctrine of St. Thomas Aquinas, and proposed by masters of philosophy, are approved." Here is the introduction: "After the Holy Father Pope Pius X, by the Motu Proprio 'Doctoris Angelici' published on June 29, 1914, wisely prescribed that in all the schools of philosophy the principles and major propositions of Thomas Aquinas should be sacredly held, not a few masters, appertaining to different institutions, proposed to this Sacred Congregation of Studies for examination some theses which they were accustomed to teach and defend as conformable to the holy Doctor's principles, especially in metaphysics. This Sacred Congregation, having duly examined the above mentioned theses, and submitted them to the Holy Father, at the command of His Holiness, replies that they clearly contain the principles and major propositions of the holy Doctor."22

By a later document, these same theses were all officially declared to contain the genuine teaching of St. Thomas.23 And to the question whether they should be imposed upon Catholic schools to be held, the Congregation answered: "Proponantur veluti tutae normae directivae."24 Proposed, not imposed: since it is philosophy, not faith, which is concerned.

But they must be proposed; namely, taught. For we have such an interpretation in the following words of Pius X: "The chief doctrines of St. Thomas' philosophy cannot be regarded as mere opinions—which anyone might discuss pro and con, but rather as a foundation on which all science of both natural and divine things rests. If they are taken away, or perverted in any way, then this necessarily follows: that the students of sacred studies will not perceive even the meaning of those words whereby the divinely revealed dogmas are uttered by the teaching of the Church."25

These theses must be taught as a sure guide of direction; sure guide of direction on the philosophical official teaching in the Church; sure guide of direction on the support, which faith derives from philosophy; and sure guide of direction on philosophical truth.

These theses are twenty-four in number. All of them are concerned with metaphysics, since it was chiefly upon the metaphysical teaching of St. Thomas that the Popes insisted. In the next issue we intend to publish a short treatise on these theses.


1 Encycl. "Aeterni Patris," August 4, 1879.

2 Motu Proprio "Doctoris Angelici," June 29, 1914.

3 Enc. "Aeterni Patris."

4 M. P. "Doctoris Angelici."

5 Enc. "Aeterni Patris."

6 Ibid.

7 Ib.

8 Ib.

9 Ib.

10 Encycl. "Pascendi," September 8, 1907.

11 Ibid.

12 Enc. "Aeterni Patris."

13 Ibid.

14 Enc. "Pascendi."

15 Motu Proprio "Sacrorum antistitum," September 1, 1910.

16 Encycl. "Aeterni Patris."

17 M. P. "Doctoris Angelici."

18 Ibid.

19 Canon 589.

20 Canon 1366, 2.

21 Enc. "Aeterni Patris."

22 Acta Apost. Sedis, August, 1914.

23 Acta Ap. Sed., May, 1916.

24 Ibid.

25 M. P. "Doctoris Angelici."

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