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,1 and left the Church which He had founded to be the common and supreme teacher of the peoples. For men whom the truth had set free were to be preserved by the truth; nor would the fruits of heavenly doctrines by which salvation comes to men have long remained had not the Lord Christ appointed an unfailing teaching authority to train the minds to faith. And the Church built upon the promises of its own divine Author, whose charity it imitated, so faithfully followed out His commands that its constant aim and chief wish was this: to teach religion and contend forever against errors. To this end assuredly have tended the incessant labors of individual bishops; to this end also the published laws and decrees of councils, and especially the constant watchfulness of the Roman Pontiffs, to whom, as successors of the blessed Peter in the primacy of the Apostles, belongs the right and office of teaching and confirming their brethren in the faith. Since, then, according to the warning of the apostle, the minds of Christ's faithful are apt to be deceived and the integrity of the faith to be corrupted among men by philosophy and vain deceit,2 the supreme pastors of the Church have always thought it their duty to advance, by every means in their power, science truly so called, and at the same time to provide with special care that all studies should accord with the Catholic faith, especially philosophy, on which a right interpretation of the other sciences in great part depends. Indeed, venerable brethren, on this very subject among others, We briefly admonished you in Our first encyclical letter; but now, both by reason of the gravity of the subject and the condition of the time, we are again compelled to speak to you on the mode of taking up the study of philosophy which shall respond most fitly to the excellence of faith, and at the same time be consonant with the dignity of human science.
2. Who so turns his attention to the bitter strifes of these days and seeks a reason for the troubles that vex public and private life must come to the conclusion that a fruitful cause of the evils which now afflict, as well as those which threaten, us lies in this: that false conclusions concerning divine and human things, which originated in the schools of philosophy, have now crept into all the orders of the State, and have been accepted by the common consent of the masses. For, since it is in the very nature of man to follow the guide of reason in his actions, if his intellect sins at all his will soon follows; and thus it happens that false opinions, whose seat is in the understanding, influence human actions and pervert them. Whereas, on the other hand, if men be of sound mind and take their stand on true and solid principles, there will result a vast amount of benefits for the public and private good. We do not, indeed, attribute such force and authority to philosophy as to esteem it equal to the task of combating and rooting out all errors; for, when the Christian religion was first constituted, it came upon earth to restore it to its primeval dignity by the admirable light of faith, diffused "not by persuasive words of human wisdom, but in the manifestation of spirit and of power",3 so also at the present time we look above all things to the powerful help of Almighty God to bring back to a right understanding the minds of man and dispel the darkness of error.4 But the natural helps with which the grace of the divine wisdom, strongly and sweetly disposing all things, has supplied the human race are neither to be despised nor neglected, chief among which is evidently the right use of philosophy. For, not in vain did God set the light of reason in the human mind; and so far is the super-added light of faith from extinguishing or lessening the power of the intelligence that it completes it rather, and by adding to its strength renders it capable of greater things.
3. Therefore, Divine Providence itself requires that, in calling back the people to the paths of faith and salvation, advantage should be taken of human science also an approved and wise practice which history testifies was observed by the most illustrious Fathers of the Church. They, indeed, were won't neither to belittle nor undervalue the part that reason had to play, as is summed up by the great Augustine when he attributes to this science "that by which the most wholesome faith is begotten . . . is nourished, defended, and made strong."5
4. In the first place, philosophy, if rightly made use of by the wise, in a certain way tends to smooth and fortify the road to true faith, and to prepare the souls of its disciples for the fit reception of revelation; for which reason it is well called by ancient writers sometimes a steppingstone to the Christian faith,6 sometimes the prelude and help of Christianity,7 sometimes the Gospel teacher.8 And, assuredly, the God of all goodness, in all that pertains to divine things, has not only manifested by the light of faith those truths which human intelligence could not attain of itself, but others, also, not altogether unattainable by reason, that by the help of divine authority they may be made known to all at once and without any admixture of error. Hence it is that certain truths which were either divinely proposed for belief, or were bound by the closest chains to the doctrine of faith, were discovered by pagan sages with nothing but their natural reason to guide them, were demonstrated and proved by becoming arguments. For, as the Apostle says, the invisible things of Him, from the creation of the world, are clearly seen, being understood by the things that are made: His eternal power also and divinity;9 and the Gentiles who have not the Law show, nevertheless, the work of the Law written in their hearts.10 But it is most fitting to turn these truths, which have been discovered by the pagan sages even, to the use and purposes of revealed doctrine, in order to show that both human wisdom and the very testimony of our adversaries serve to support the Christian faith-a method which is not of recent introduction, but of established use, and has often been adopted by the holy Fathers of the Church. What is more, those venerable men, the witnesses and guardians of religious traditions, recognize a certain form and figure of this in the action of the Hebrews, who, when about to depart out of Egypt, were commanded to take with them the gold and silver vessels and precious robes of the Egyptians, that by a change of use the things might be dedicated to the service of the true God which had formerly been the instruments of ignoble and superstitious rites. Gregory of NeoCaesarea11 praises Origen expressly because, with singular dexterity, as one snatches weapons from the enemy, he turned to the defense of Christian wisdom and to the destruction of superstition many arguments drawn from the writings of the pagans. And both Gregory of Nazianzen12 and Gregory of Nyssa13 praise and commend a like mode of disputation in Basil the Great; while Jerome14 especially commends it in Quadratus, a disciple of the Apostles, in Aristides, Justin, Irenaeus, and very many others. Augustine says: "Do we not see Cyprian, that mildest of doctors and most blessed of martyrs, going out of Egypt laden with gold and silver and vestments? And Lactantius, also and Victorinus, Optatus and Hilary? And, not to speak of the living, how many Greeks have done likewise?"15 But if natural reason first sowed this rich field of doctrine before it was rendered fruitful by the power of Christ, it must assuredly become more prolific after the grace of the Saviour has renewed and added to the native faculties of the human mind. And who does not see that a plain and easy road is opened up to faith by such a method of philosophic study?
5. But the advantage to be derived from such a school of philosophy is not to be confined within these limits. The foolishness of those men who "by these good things that are seen could not understand Him, that is, neither by attending to the works could have acknowledged who was the workman,"16 is gravely reproved in the words of Divine Wisdom. In the first place, then, this great and noble fruit is gathered from human reason, that it demonstrates that God is; for the greatness of the beauty and of the creature the Creator of them may be seen so as to be known thereby.17 Again, it shows God to excel in the height of all perfections, especially in infinite wisdom before which nothing lies hidden, and in absolute justice which no depraved affection could possibly shake; and that God, therefore, is not only true but truth itself, which can neither deceive nor be deceived. Whence it clearly follows that human reason finds the fullest faith and authority united in the word of God. In like manner, reason declares that the doctrine of the Gospel has even from its very beginning been made manifest by certain wonderful signs, the established proofs, as it were, of unshaken truth; and that all, therefore, who set faith in the Gospel do not believe rashly as though following cunningly devised fables,18 but, by a most reasonable consent, subject their intelligence and judgment to an authority which is divine. And of no less importance is it that reason most clearly sets forth that the Church instituted by Christ (as laid down in the Vatican Council), on account of its wonderful spread, its marvelous sanctity, and its inexhaustible fecundity in all places, as well as of its Catholic unity and unshaken stability, is in itself a great and perpetual motive of belief and an irrefragable testimony of its own divine mission.19
6. Its solid foundations having been thus laid, a perpetual and varied service is further required of philosophy, in order that sacred theology may receive and assume the nature, form, and genius of a true science. For in this, the most noble of studies, it is of the greatest necessity to bind together, as it were, in one body the many and various parts of the heavenly doctrines, that, each being allotted to its own proper place and derived from its own proper principles, the whole may join together in a complete union; in order, in fine, that all and each part may be strengthened by its own and the others' invincible arguments. Nor is that more accurate or fuller knowledge of the things that are believed, and somewhat more lucid understanding, as far as it can go, of the very mysteries of faith which Augustine and the other fathers commended and strove to reach, and which the Vatican Council itself20 declared to be most fruitful, to be passed over in silence or belittled. Those will certainly more fully and more easily attain that knowledge and understanding who to integrity of life and love of faith join a mind rounded and finished by philosophic studies, as the same Vatican Council teaches that the knowledge of such sacred dogmas ought to be sought as well from analogy of the things that are naturally known as from the connection of those mysteries one with another and with the final end of man.21
7. Lastly, the duty of religiously defending the truths divinely delivered, and of resisting those who dare oppose them, pertains to philosophic pursuits. Wherefore, it is the glory of philosophy to be esteemed as the bulwark of faith and the strong defense of religion. As Clement of Alexandria testifies, the doctrine of the Saviour is indeed perfect in itself and wanteth naught, since it is the power and wisdom of God. And the assistance of the Greek philosophy maketh not the truth more powerful; but, inasmuch as it weakens the contrary arguments of the sophists and repels the veiled attacks against the truth, it has been fitly called the hedge and fence of the vine.22 For, as the enemies of the Catholic name, when about to attack religion, are in the habit of borrowing their weapons from the arguments of philosophers, so the defenders of sacred science draw many arguments from the store of philosophy which may serve to uphold revealed dogmas. Nor is the triumph of the Christian faith a small one in using human reason to repel powerfully and speedily the attacks of its adversaries by the hostile arms which human reason itself supplied. This species of religious strife St. Jerome, writing to Magnus, notices as having been adopted by the Apostle of the Gentiles himself; Paul, the leader of the Christian army and the invincible orator, battling for the cause of Christ, skillfully turns even a chance inscription into an argument for the faith; for he had learned from the true David to wrest the sword from the hands of the enemy and to cut off the head of the boastful Goliath with his own weapon.23 Moreover, the Church herself not only urges, but even commands, Christian teachers to seek help from philosophy. For, the fifth Lateran Council, after it had decided that "every assertion contrary to the truth of revealed faith is altogether false, for the reason that it contradicts, however slightly, the truth,"24 advises teachers of philosophy to pay close attention to the exposition of fallacious arguments; since, as Augustine testifies, "if reason is turned against the authority of sacred Scripture, no matter how specious it may seem, it errs in the likeness of truth; for true it cannot be."25
8. But in order that philosophy may be bound equal to the gathering of those precious fruits which we have indicated, it behooves it above all things never to turn aside from that path which the Fathers have entered upon from a venerable antiquity, and which the Vatican Council solemnly and authoritatively approved. As it is evident that very many truths of the supernatural order which are far beyond the reach of the keenest intellect must be accepted, human reason, conscious of its own infirmity, dare not affect to itself too great powers, nor deny those truths, nor measure them by its own standard, nor interpret them at will; but receive them, rather, with a full and humble faith, and esteem it the highest honor to be allowed to wait upon heavenly doctrines like a handmaid and attendant, and by God's goodness attain to them in any way whatsoever. But in the case of such doctrines as the human intelligence may perceive, it is equally just that philosophy should make use of its own method, principles, and arguments - not, indeed, in such fashion as to seem rashly to withdraw from the divine authority. But, since it is established that those things which become known by revelation have the force of certain truth, and that those things which war against faith war equally against right reason, the Catholic philosopher will know that he violates at once faith and the laws of reason if he accepts any conclusion which he understands to be opposed to revealed doctrine.
9. We know that there are some who, in their overestimate of the human faculties, maintain that as soon as man's intellect becomes subject to divine authority it falls from its native dignity, and hampered by the yoke of this species of slavery, is much retarded and hindered in its progress toward the supreme truth and excellence. Such an idea is most false and deceptive, and its sole tendency is to induce foolish and ungrateful men wilfully to repudiate the most sublime truths, and reject the divine gift of faith, from which the fountains of all good things flow out upon civil society. For the human mind, being confined within certain limits, and those narrow enough, is exposed to many errors and is ignorant of many things; whereas the Christian faith, reposing on the authority of God, is the unfailing mistress of truth, whom who so followeth he will be neither enmeshed in the snares of error nor tossed hither and thither on the waves of fluctuating opinion. Those, therefore, who to the study of philosophy unite obedience to the Christian faith, are philosophizing in the best possible way; for the splendor of the divine truths, received into the mind, helps the understanding, and not only detracts in no wise from its dignity, but adds greatly to its nobility, keenness, and stability. For surely that is a worthy and most useful exercise of reason when men give their minds to disproving those things which are repugnant to faith and proving the things which conform to faith. In the first case they cut the ground from under the feet of error and expose the viciousness of the arguments on which error rests; while in the second case they make themselves masters of weighty reasons for the sound demonstration of truth and the satisfactory instruction of any reasonable person. Whoever denies that such study and practice tend to add to the resources and expand the faculties of the mind must necessarily and absurdly hold that the mind gains nothing from discriminating between the true and the false. Justly, therefore, does the Vatican Council commemorate in these words the great benefits which faith has conferred upon reason: Faith frees and saves reason from error, and endows it with manifold knowledge.26 A wise man, therefore, would not accuse faith and look upon it as opposed to reason and natural truths, but would rather offer heartfelt thanks to God, and sincerely rejoice that, in the density of ignorance and in the flood-tide of error, holy faith, like a friendly star, shines down upon his path and points out to him the fair gate of truth beyond all danger of wandering.
10. If, venerable brethren, you open the history of philosophy, you will find all We have just said proved by experience. The philosophers of old who lacked the gift of faith, yet were esteemed so wise, fell into many appalling errors. You know how often among some truths they taught false and incongruous things; what vague and doubtful opinions they held concerning the nature of the Divinity, the first origin of things, the government of the world, the divine knowledge of the future, the cause and principle of evil, the ultimate end of man, the eternal beatitude, concerning virtue and vice, and other matters, a true and certain knowledge of which is most necessary to the human race; while, on the other hand, the early Fathers and Doctors of the Church, who well understood that, according to the divine plan, the restorer of human science is Christ, who is the power and the wisdom of God,27 and in whom are hid all the treasures of wisdom and knowledge,28 took up and investigated the books of the ancient philosophers, and compared their teachings with the doctrines of revelation, and, carefully sifting them, they cherished what was true and wise in them and amended or rejected all else. For, as the all-seeing God against the cruelty of tyrants raised up mighty martyrs to the defense of the Church, men prodigal of their great lives, in like manner to false philosophers and heretics He opposed men of great wisdom, to defend, even by the aid of human reason, the treasure of revealed truths. Thus, from the very first ages of the Church, the Catholic doctrine has encountered a multitude of most bitter adversaries, who, deriding the Christian dogmas and institutions, maintained that there were many gods, that the material world never had a beginning or cause, and that the course of events was one of blind and fatal necessity, not regulated by the will of Divine Providence.
11. But the learned men whom We call apologists speedily encountered these teachers of foolish doctrine and, under the guidance of faith, found arguments in human wisdom also to prove that one God, who stands pre-eminent in every kind of perfection, is to be worshiped; that all things were created from nothing by His omnipotent power; that by His wisdom they flourish and serve each their own special purposes. Among these St. Justin Martyr claims the chief place.
After having tried the most celebrated academies of the Greeks, he saw clearly, as he himself confesses, that he could only draw truths in their fullness from the doctrine of revelation. These he embraced with all the ardor of his soul, purged of calumny, courageously and fully defended before the Roman emperors, and reconciled with them not a few of the sayings of the Greek philosophers.
12. Quadratus, also, and Aristides, Hermias, and Athenagoras stood nobly forth in that time. Nor did Irenaeus, the invincible martyr and Bishop of Lyons, win less glory in the same cause when, forcibly refuting the perverse opinions of the Orientals, the work of the Gnostics, scattered broadcast over the territories of the Roman Empire, he explained (according to Jerome) the origin of each heresy and in what philosophic source it took its rise.29 But who knows not the disputations of Clement of Alexandria, which the same Jerome thus honorably commemorates: "What is there in them that is not learned, and what that is not of the very heart of philosophy?"30 He himself, indeed, with marvelous versatility treated of many things of the greatest utility for preparing a history of philosophy, for the exercise of the dialectic art, and for showing the agreement between reason and faith. After him came Origen, who graced the chair of the school of Alexandria, and was most learned in the teachings of the Greeks and Orientals. He published many volumes, involving great labor, which were wonderfully adapted to explain the divine writings and illustrate the sacred dogmas; which, though, as they now stand, not altogether free from error, contain nevertheless a wealth of knowledge tending to the growth and advance of natural truths. Tertullian opposes heretics with the authority of the sacred writings; with the philosophers he changes his fence and disputes philosophically; but so learnedly and accurately did he confute them that he made bold to say: "Neither in science nor in schooling are we equals, as you imagine."31 Arnobius, also, in his works against the pagans, and Lactantius in the divine Institutions especially, with equal eloquence and strength strenuously strive to move men to accept the dogmas and precepts of Catholic wisdom, not by philosophic juggling, after the fashion of the Academicians, but vanquishing them partly by their own arms, and partly by arguments drawn from the mutual contentions of the philosophers.32 But the writings on the human soul, the divine attributes, and other questions of mighty moment which the great Athanasius and Chrysostom, the prince of orators, have left behind them are, by common consent, so supremely excellent that it seems scarcely anything could be added to their subtlety and fulness. And, not to cover too wide a range, we add to the number of the great men of whom mention has been made the names of Basil the Great and of the two Gregories, who, on going forth from Athens, that home of all learning, thoroughly equipped with all the harness of philosophy, turned the wealth of knowledge which each had gathered up in a course of zealous study to the work of refuting heretics and preparing Christians.
13. But Augustine would seem to have wrested the palm from all. Of a most powerful genius and thoroughly saturated with sacred and profane learning, with the loftiest faith and with equal knowledge, he combated most vigorously all the errors of his age. What topic of philosophy did he not investigate? What region of it did he not diligently explore, either in expounding the loftiest mysteries of the faith to the faithful, or defending them against the full onslaught of adversaries, or again when, in demolishing the fables of the Academicians or the Manichaeans, he laid the safe foundations and sure structure of human science, or followed up the reason, origin, and causes of the evils that afflict man? How subtly he reasoned on the angels, the soul, the human mind, the will and free choice, on religion and the life of the blessed, on time and eternity, and even on the very nature of changeable bodies. Afterwards, in the East, John Damascene, treading in the footsteps of Basil and of Gregory of Nazianzen, and in the West, Boethius and Anselm following the doctrines of Augustine, added largely to the patrimony of philosophy.
14. Later on, the doctors of the middle ages, who are called Scholastics, addressed themselves to a great work-that of diligently collecting, and sifting, and storing up, as it were, in one place, for the use and convenience of posterity the rich and fertile harvests of Christian learning scattered abroad in the voluminous works of the holy Fathers. And with regard, venerable brethren, to the origin, drift, and excellence of this scholastic learning, it may be well here to speak more fully in the words of one of the wisest of Our predecessors, Sixtus V: "By the divine favor of Him who alone gives the spirit of science wisdom, and understanding, and who thou ages, as there may be need, enriches His Church with new blessings and strengthens it with safeguards, there was founded by Our fathers, men of eminent wisdom, the scholastic theology, which two glorious doctors in particular angelic St. Thomas and the seraphic St. Bonaventure, illustrious teachers of this faculty, . . .with surpassing genius, by unwearied diligence, and at the cost of long labors and vigils, set in order and beautified, and when skillfully arranged and clearly explained in a variety of ways, handed down to posterity.
15. "And, indeed, the knowledge and use of so salutary a science, which flows from the fertilizing founts of the sacred writings, the sovereign Pontiffs, the holy Fathers and the councils, must always be of the greatest assistance to the Church, whether with the view of really and soundly understanding and interpreting the Scriptures, or more safely and to better purpose reading and explaining the Fathers, or for exposing and refuting the various errors and heresies; and in these late days, when those dangerous times described by the Apostle are already upon us, when the blasphemers, the proud, and the seducers go from bad to worse, erring themselves and causing others to err, there is surely a very great need of confirming the dogmas of Catholic faith and confuting heresies."
16. 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, that strength of argument and those keen discussions, 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"33 - 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.
17. Among the Scholastic Doctors, the chief and master of all towers Thomas Aquinas, who, as Cajetan observes, because "he most venerated the ancient doctors of the Church, in a certain way seems to have inherited the intellect of all."34 The doctrines of those illustrious men, like the scattered members of a body, Thomas collected together and cemented, distributed in wonderful order, and so increased with important additions that he is rightly and deservedly esteemed the special bulwark and glory of the Catholic faith. With his spirit at once humble and swift, his memory ready and tenacious, his life spotless throughout, a lover of truth for its own sake, richly endowed with human and divine science, like the sun he heated the world with the warmth of his virtues and filled it with the splendor of his teaching. Philosophy has no part which he did not touch finely at once and thoroughly; on the laws of reasoning, on God and incorporeal substances, on man and other sensible things, on human actions and their principles, he reasoned in such a manner that in him there is wanting neither a full array of questions, nor an apt disposal of the various parts, nor the best method of proceeding, nor soundness of principles or strength of argument, nor clearness and elegance of style, nor a facility for explaining what is abstruse.