The Arabians

Two notable philosophers among the Mohammedan Arabs of the Middle Ages must be mentioned here. These are Ibn-Sina (more commonly called by the Latinized form of his name Avicenna) and Ibn-Roschd (usually called Averroes).

Avicenna (980-1037) was a native of Bokhara; his parents were Persian-born Arabians. He was a man of intellectual gifts. A physician of renown as well as a philosopher, he is forever memorable for his book, The Canons of Medicine, which served for many years as the standard textbook for students of medical science.

Averroes (d. 1198) was a Spanish=born Arab. He was a notable commentator on Aristotle as well as a distinguished thinker in his own right. The fact that the question of universals was of burning importance in the Middle Ages explains the enduring of these Arab names. For the Arabians were deeply interested in the origin of ideas, and their theories touched the very heart of the controversy on universals.

The true doctrine on ideas may be summed up thus: there are no inborn ideas; man acquires all his knowledge. Ideas result in man's intellect from the action of the mind on the findings of sense. From these ideas others may be worked out by a further process of abstraction. So the mind rises from those ideas immediately formed upon sense-action (physical ideas) to concepts of pure quantity (mathematical ideas) and concepts of being considered apart from all the limitations of materiality (metaphysical ideas).

In a word, ideas have their origin in the native power of the human mind or intellect to abstract understandable essences (called intelligible species) from sense-findings, and to hold these within itself as representations of reality. Each human being has a mind or intellect. The intellect, in so far as it abstracts ideas (or intelligible species) from sense-findings (and from ideas already formed) is called the intellectus agens or active intellect; in so far as it expresses within itself the abstracted essences or intelligible species and holds these as representations of reality (thus knowing reality), it is called the intellectus possibilis or understanding intellect.

Now, the Arabians who followed Avicenna held the strange doctrine that there is a common intellectus agens for all men, jus as there is one sun in the sky to lend light to all eyes. Averroes and his followers went further; they taught that the intellect, both agens and possibilis, is a common possession, a reality outside all individual men.

Individual man has no intellect at all. His knowing-power is merely that of the senses. And, since the senses are organic (that is, dependent on bodily members), there is no justification for the conclusion that man has spiritual element in his make-up. Therefore, man has no spiritual soul; when he dies he perishes utterly. So far Averroes the philosopher.

But Averroes the theologian, holding fast to the Koran, teaches that man has an immortal soul. Here we have the beginning of that most disastrous of all doctrines, against which the mighty Thomas Aquinas was to rise in towering strength: the doctrine of a twofold truth. This pernicious doctrine holds that what is true in philosophy may be false in theology, and vice versa. The twofold-truth doctrine was taught in the 13th century by Siger of Brabant in the University of Paris. The doctrine is wholly indefensible, and it leads directly into the insane self-contradiction of skepticism. It is ruinous of all knowledge, of all science, of all philosophy.

The doctrine of twofold-truth is no longer defended by theorists; Aquinas put an enduring end to all discussion of the matter. But it endures in practice, especially in the form of a twofold morality. Thus there are people who will justify sharp practice and open savagery by quoting as sound principles the silly clichs, "Business is business," and "All's fair in war," -- as though the businessman and the soldier had a set of moral laws for office hours or term of service, and another set for private life. Truth is one, constant, consistent.

One truth cannot come in conflict with another truth. And the truth of morality is like all other truths. There can be no such thing as a diversity of moral principles to suit diversity of persons or circumstances.


Albert the Great, known to his contemporaries as Albert of Cologne, and frequently called by the Latin form of his name, Albertus Magnus, was born in Swabia, part of present Germany, in the last years of the 12th century or the first years of the 13th. He died in 1280. Albert was a member of the Order of St. Dominic; he was made Bishop of Ratisbon in 1260. Preeminently a student and teacher, he resigned his bishop's see after three years of office. Most of his teaching was done at the universities of Paris and Cologne.

Albert is called "The Universal Doctor," and the name is justified, for he was a man of enormous capacity for learning and of tireless diligence in study and research. His works are many, and they cover wide and various fields -- philosophy, theology, Scripture, natural science. His genius was analytical; he worked out an amazing amount of scientific knowledge. The synthetical power which collates, integrates, focusses, and refines the fruits of analysis, was not so marked a gift of Albert, although he certainly possessed it in good measure.

Albert was an Aristotelian. He purified the translations of Aristotle of much Arabian interpolation. In his treatise on Aristotle's Physics, as well as in his own studies and experiments, Albert contributed more to the development of physical science than did the much lauded Roger Bacon.

Albert's work was notable and it was nobly done. It stands upon its own merits. But, looking upon it in retrospect, we must judge that Albert's greatest service to philosophy was the fact that he prepared the ground, so to speak, for the work of his illustrious pupil, Thomas Aquinas.

Part III: From Thomas Aquinas to William of Ockham


Thomas of Aquin -- more commonly called Thomas Aquinas, or simply Aquinas -- was born during the young manhood of Albert and died before him. Yet it seems natural for us to think of Aquinas appearing on the intellectual scene after Albert had departed. He was a pupil of Albert, and this enlightened teacher recognized his genius in early student days when fellow pupils considered Aquinas only a dreamy lad of no particular talent.

Aquinas was born between 1224 and 1226 in Roccasecca in Italy. He died March 7, 1274, while on his way to attend the Council of Lyons. Thus he lived, at most, but fifty years. Yet the accomplishments of his comparatively short lifetime were enough, one might suppose, for twenty men of twice his span of years.

If we except Aristotle, and perhaps Augustine, the history of philosophy has no name to offer that deserves to stand in the same line with that of Thomas Aquinas. It may be unfair to compare Aquinas with Aristotle, for Aristotle worked in the night of pagan antiquity while Aquinas labored in the daylight of Christianity. Perhaps it is but just to say that, in point of natural gifts, Aristotle stands alone, and that, in point of natural and supernatural gifts combined, Aquinas far surpasses Aristotle.

Aquinas produced a veritable library of valuable writings. These are remarkable for their scope, their completeness, their clarity. No taint of pride, no vain show of erudition for its own sake, soils any page he wrote. No man ever knew more thoroughly, and more sympathetically, the significant writings of all his predecessors in philosophy, theology, Scripture, and physical science. Thoroughly equipped with an easy mastery of the world's worthwhile knowledge, Aquinas brought to bear upon every question the light of his own mighty and original mind. In him the power of analysis and the power of synthesis seem equal.

Following the lead of Albert, Aquinas purified many doctrines attributed to Aristotle of their Mohammedan accretions, and he induced his friend and fellow-Dominican, William of Moerbeke, an able linguist, to make a Latin translation of Aristotle from the original Greek.

Aquinas settled the perplexing question of the distinction between philosophy and theology by justifying the principle: Sciences are distinguished one from another by their respective formal objects, and ultimately by the method or methods they use.

In the matter of universals, Aquinas offers compelling proof for the truth of the Aristotelian doctrine of Moderate Realism. He devotes full and detailed study to the basic concept or idea of being. This concept is the first idea in every order -- the order of time (chronological order), the order of knowledge (logical order), and the order of understandable reality (metaphysical order). For the very first idea or concept acquired in life (since we are born without any equipment of ideas) is the idea of some thing, that is, of some being, and the notion of some being involves, implicitly, the notion or idea of being as such.

Further, the analysis of every concept takes the mind back to the fundamental notion of being. And, finally, every reality that can be thought of as existing is necessarily understood as some thing, that is, as being. The idea of being is truly transcendental. Other transcendental ideas which extend or specially apply the idea of being are distinct from the idea of being by only a distinction of reason (i.e., logical distinction) not a real distinction. These ideas are: thing, something, reality, the one, the good, the true. Together with being, these are called "the transcendentals."

Aquinas holds the sane Aristotelian doctrine that all human knowledge takes its beginning in the action of the senses on the bodily world around us. He rejects the Augustinian theory that a special divine illumination is required for certain kinds of knowledge -- such as knowledge of first principles, or knowledge of spiritual realities. Our natural knowledge, says Aquinas, is due to the fact that the mind is equipped with a power of abstraction which it employs first upon the findings of the senses, and then upon ideas themselves for their further refinement or elaboration.

Thus the mind arises from the physical order, through the mathematical order, to the metaphysical order of concepts or ideas. Thus there are three grades of abstraction. These are truly grades or degrees; they are not merely kinds; they are like steps in one stairway. Aquinas takes the three grades of abstraction as the basis for the general classification of sciences.

In point of physical philosophy, Aquinas holds with Aristotle that all physical being (that is, all being subject to change) is compounded of actuality and potentiality (actus et potentia). Further, all bodily being (all ens mobile) is composed of matter and form, and, fundamentally, of prime matter and substantial form. Aquinas teaches that, at any given moment, only one substantial form can in-form or actualize the same prime matter; in this point, he differs from the view (Scotistic and Franciscan) of those philosophers who defend the "plurality-of-substantial-forms theory." Spiritual substances are pure forms.

The principle of specification, by which one essential kind of substance is distinguished from every other kind, is substantial form. The principle of individuation, by which individual substances of the same species or kind are distinguished from one another, is in-formed prime matter as quantified.

Aquinas holds that the human soul is, in each man, the substantial form of the living body. The soul does not exist before its union with the body. At one and the same instant each soul is created and infused (i.e., substantially united with the body) by God.

Aquinas rejects the Arabian doctrine of a separate and common intellect serving all men, and offers proofs for the existence of intellect as a faculty of each human individual. He shows that man has freewill, that is, that the human will is endowed with the freedom of choice of means to the necessary (and not free) ultimate end, the Supreme Good.

In point of metaphysical philosophy, Aquinas treats of being in itself, of being as it is in the mind (that is, truth and certitude). He asserts a real distinction (not merely a rational or logical distinction) between the essence and the existence of an existing creature. He extends Aristotle's doctrine of causes, and deals most profoundly with the effecting or efficient cause, and with its subsidiary, the instrumental cause.

He shows that God is First Effecting Cause, that the divine "effectingness," as act and as power, is identified with the Divine Substance. In creatures "effectingness" (or efficiency) as act and power is something really distinct from their substance; it is something they have, not something which they are; hence, faculties are things really distinct from the creatural substance which possesses and exercises them.

Aquinas shows that God, the Necessary and Self-Subsistent First Being, is the Effecting, the Final, and the Exemplar Cause of all perfection, that is, of all positive being. He shows how God concurs with creatures in their connatural activities, and he maintains that the divine concurrence is not only simultaneous with the actions of creations, but antecedent to such action; yet such antecedent concurrence (called physical premotion) in no wise destroys the nature of the acting creature; even if the creature be free, its freedom is not destroyed or in any sense hindered, for "God moves every being in a manner consonant with its nature."

In point of moral philosophy or ethics, Aquinas shows that man, in every human act (that is in every thought, word, deed, or omission which is done knowingly and freely), tends towards the Supreme Good, the possession of which will constitute man in the state of perfect beatitude. Even the sinner, perversely choosing evil, chooses it under the guise of good, that is, of something that will satisfy. Man is made for God and endless perfect happiness. This end cannot be achieved perfectly this side of heaven, but it can be approximated here on earth by living for God, by knowing, loving, serving God.

Since God has made man for Himself and happiness, He has a plan, an arrangement, a law which man must follow to attain His end. In other words, the Divine Reason (that is, God as Intellect and Will) has established the law which directs all things to their last goal or end. This law is The Eternal Law. Man, when he comes to the use and practice of his mental powers, inevitably becomes aware of "an order in things" which he must not disturb but must conserve; man's awareness of The Eternal Law is "the natural law." And man, in all his human acts, inevitably sees them in their relation to the natural law, and mentally pronounces upon their agreement or disagreement with the natural law. Such a pronouncement is called a judgment of conscience. And thus we notice that the norm of morality is The Eternal Law as applied by conscience.

Aquinas has been called, and with justice, the prince of philosophers and of theologians. His works merit the earnest study of every thoughtful mind.


John Duns Scotus (1266/74-1308), a member of the Franciscan Order, was a philosopher of extraordinary gifts and of wondrous accomplishment. He studied at Oxford, and later taught there and at the University of Paris. He wrote commentaries on Aristotle and on other philosophers, and he produced a notable treatise on theology.

He also wrote Quaestiones Quodlibetales, a discussion of a variety of questions. Many other works are attributed to Scotus. The scholarly researches of the Franciscan Friars in our own day have shown beyond doubt or question that some of these works are spurious, and that some theories long attributed to Scotus are not truly his.

Scotus is known as "the Subtle Doctor." He had a mind of marvelous acuteness, and an untiring zeal for intricacies of discussion in which none but the keenest and most devoted students could keep pace with him. In some points he disagrees with Thomas Aquinas. For instance, he has small reliance on the unaided human reason as the basis of certitude, and requires Faith and Revelation for the solution of some problems of philosophy.

He does not agree with Aquinas in point of "the principle of individuation" which he holds to be, not quantified matter, but a positive reality added to a being fully constituted in its specific nature; he calls this positive individuating reality by the name of haecceitas, which might be clumsily translated as the "thisness" of the being in question.

Again, Scotus teaches that in a created being there is not a real distinction between existence and essence, nor is there merely a rational or logical distinction; the distinction in this instance is an actual formal distinction arising from the nature of the reality in which the distinction is found. This distinction (usually called "the Scotistic formal distinction") is, therefore, something less than real distinction, and something more than logical distinction.

Again, in point of universals, Scotus accepts Moderate Realism, but his expression is involved, and some critics interpret him in such wise as to make him an Ultra-Realist.

Again, Scotus defends the "plurality-of-forms-theory"; he holds that in man, in addition to the spiritual soul which is the substantial form of living man, there is a substantial body-form or "a form of corporeity."

Scotus holds that man is not moved, in his freewill acts, by the ultimate practical judgment of the mind (the ultimum judicium practicum), but that this judgment is only a condition requisite for the will's uninfluenced action.

Scotus holds with unwavering certitude to the spirituality and immortality of the human soul, yet he teaches that is immortality is proved by an appeal to Revelation, and not by unaided reason.

A man of the highest gifts, Scotus has had, and has today, a mighty influence among Scholastic philosophers. He was the great luminary of the Franciscans as Aquinas was the light and oracle of the Dominicans. The Thomist and the Scotist schools are in lively existence at the present time, especially in the realm of speculative theology.


William of Ockham was a notable Franciscan philosopher of the 14th century. He was born about 1280 and died in 1348. The name by which this philosopher is most commonly known is that of his home town, Ockham or Ockam, of Surrey in England.

William was of impulsive and even stormy temperament, and his life was not without troubles. He wrote commentaries on the philosophy of Aristotle, on the famous "Sentences" (that is, doctrines) of Peter the Lombard, and on the writings of Porphyry.

His contemporaries hailed William as "the Venerable Inceptor" of a theory of knowledge called Terminism. But this was really no new theory; it was merely Nominalism in a new dress and with a new name.

William of Ockham is memorable for one valuable rule for philosophers, Entia non sunt multiplicanda sine necessitate, which, translated literally, means, "Things are not to be multiplied without need"; the force of the rule might be given in this fashion, "Explanations are to be made in the simplest and most direct fashion which the facts allow, without needless complications and distinctions." This dictum came to be known as "Ockham's Razor," for it was formulated to cut away wasted verbiage and needless involvement of reasoning.

It is a good rule, but William himself used it without nice discernment of when "multiplication of things" is actually necessary. He sometimes used the "razor," not only to remove extraneous matters, but to level off the features of his subject. Like all impatient men who want to make complicated matters simple, he sometimes turned simplification into falsification.

This note of impatience, this eagerness to make the deepest and most complicated questions as simple as A-B-C, was -- as is always the case when it appears in the works of men of influence -- a sign of decadence in philosophy. For any impatience with multitudinous detail indicates a loss of the philosophic temper which must be tirelessly patient.

Ockham is the symbol and mark of a turning-point in philosophy. He is the last great figure in the age of perfection; some make him the first great figure in the age of transition, even when they try to hide the fact that the transition was also a retrogression. The cord of strong philosophic thought which had begun to fray under the friction of Thomistic-Scotistic argument, snapped asunder under the impatient dicta of William of Ockham. It was literally cut by "Ockham's Razor."

The Period of Evangelization


Christianity is essentially religion; that is the basis of its distinction from philosophy. Philosophy is the work of rational speculation. It is reason which, starting from a few rational principles, tries to solve the supreme metaphysical problems regarding God, the world and man.

Religion does not demonstrate, but affirms. It presents itself as a proposition of wisdom, as a positive assertion expressed in the form of dogma, and does not appeal to the intellect but to the will, whose assent it requests. Religion does not require the affirmation of the will on the basis of the intrinsic rationality which appears to the intellect but because of extrinsic motives -- that is, the authority presenting the assertion.

Religion, therefore, is distinguished from philosophy in that the former works on the will, the latter on the intellect. And the assent of the will, which in philosophy is justified only by reason, in religion is justified by authority.

Although Christianity does not present itself as a philosophy, it presupposes a specific conception of the world and life, so that its dogmas include, on religious grounds, the solution of the greatest metaphysical problems that range from God to matter.

Moreover, while Christianity is distinct from philosophy, it does not follow that the two are opposed; in fact, the indirect solution which religion gives to paramount questions in metaphysics is to be maintained as valid help to reason in its speculations. Christianity has truly integrated philosophy.

Greek philosophy failed to resolve the problem of the origin of matter and that of the presence of evil. Christianity solved the first question by introducing the concept of creation: matter does not exist from eternity, but is created by God as is the whole universe.

Christianity solved also the question of the presence of evil through the mysteries of the first fall of man, of the Incarnation and the Redemption. The doctrine of the first fall teaches that the first begotten man was not only exempt from physical and moral evil, but was elevated to a supernatural order with an abundant equipment of preternatural gifts. But because of the sin of pride committed by the first man, mankind was subjected to physical and moral evil.

The mysteries of the Incarnation and Redemption teach that the Word of God became flesh and died upon the cross not only to pay the debt of sin contracted by mankind, but also to give God the complete satisfaction and glory of which He is worthy.

Physical and moral evil still remain after the sacrifice of the cross, because everyone by suffering may take part in this sacrifice and give to God expiation for sin, and the glory of which He is worthy.

Thus, Christianity claims to have solved the problems which human reason is unable to solve by itself. This is the backdrop for an understanding of medieval philosophy.