Summa Theologica Part I

by William C. Michael

Treatise on God

- The Nature and Extent of Sacred Doctrine
- The Existence of God
- On the Simplicity of God
- The Perfection of God
- Of Goodness in General
- The Goodness of God
- The Infinity of God
- The Existence of God in Things
- The Immutability of God
- The Eternity of God
- The Unity of God
- How God Is Known by Us
- The Names of God
- Of God’s Knowledge
- Of Ideas
- Of Truth
- Concerning Falsity
- The Life of God
- The Will of God
- God’s Love
- The Justice and Mercy of God
- The Providence of God
- Of Predestination
- The Book of Life
- The Power of God
- Of the Divine Beatitude
- The Procession of the Divine Persons
- The Divine Relations
- The Divine Persons
- The Plurality of Persons in God
- Of What Belongs to the Unity or Plurality in God
- The Knowledge of the Divine Persons
- Of the Person of the Father
- Of the Person of the Son
- Of the Image
- Of the Person of the Holy Ghost
- Of the Name of the Holy Ghost — Love
- Of the Name of the Holy Ghost, as Gift
- Of the Persons in Relation to the Essence
- Of the Persons as Compared to the Relations or Properties
- Of the Persons in Reference to the Notional Acts
- Of Equality and Likeness Among the Divine Persons
- The Mission of the Divine Persons

Treatise on the Creation

- The Procession of Creatures from God, and of the First Cause of All Things
- The Mode of Emanation of Things from the First Principle
- Of the Beginning of the Duration of Creatures
- Of the Distinction of Things in General
- The Distinction of Things in Particular
- The Cause of Evil

Treatise on the Angels

- Of the Substance of the Angels Absolutely Considered
- Of the Angels in Comparison with Bodies
- Of the Angels in Relation to Place
- Of the Local Movement of the Angels
- Of the Knowledge of the Angels
- Of the Medium of the Angelic Knowledge
- Of the Angels’ Knowledge of Immaterial Things
- Of the Angels’ Knowledge of Material Things
- Of the Mode of the Angelic Knowledge
- The Will of the Angels
- Of the Love or Dilection of the Angels
- Of the Production of the Angels in the Order of Natural Being
- Of the Perfection of the Angels in the Order of Grace and of Glory
- The Malice of the Angels with Regard to Sin
- The Punishment of the Demons

Treatise on the Work of the six Days

- The Work of Creation of Corporeal Creatures
- On the Order of Creation Towards Distinction
- On the Work of Distinction in Itself
- On the Work of the Second Day
- On the Work of the Third Day
- On the Work of Adornment, as Regards the Fourth Day
- On the Work of the Fifth Day
- On the Work of the Sixth Day
- On the Things That Belong to the Seventh Day
- On All the Seven Days in Common

Treatise on Man

- Of Man Who Is Composed of a Spiritual and a Corporeal Substance: and in the First Place, Concerning What Belongs to the Essence of the Soul
- Of the Union of Body and Soul
- Of Those Things Which Belong to the Powers of the Soul in General
- Of the Specific Powers of the Soul
- Of the Intellectual Powers
- Of the Appetitive Powers in General
- Of the Power of Sensuality
- Of the Will
- Of Free-Will
- How the Soul While United to the Body Understands Corporeal Things Beneath It
- Of the Mode and Order of Understanding
- What Our Intellect Knows in Material Things
- How the Intellectual Soul Knows Itself and All Within Itself
- How the Human Soul Knows What Is Above Itself
- Of the Knowledge of the Separated Soul
- Of the First Production of Man’s Soul
- The Production of the First Man’s Body
- The Production of the Woman
- The End or Term of the Production of Man
- Of the State and Condition of the First Man as Regards His Intellect
- Of Things Pertaining to the First Man’s Will — Namely, Grace and Righteousness
- Of the Mastership Belonging to Man in the State of Innocence
- Of the Preservation of the Individual in the Primitive State
- Of the Preservation of the Species
- Of the Condition of the Offspring As to the Body
- Of the Condition of the Offspring As Regards Righteousness
- Of the Condition of the Offspring As Regards Knowledge
- Of Man’s Abode, Which Is Paradise

Treatise on the Divine Government

- Of the Government of Things in General
- The Special Effects of the Divine Government
- Of the Change of Creatures by God
- How One Creature Moves Another
- The Speech of the Angels
- Of the Angelic Degrees of Hierarchies and Orders
- The Ordering of the Bad Angels
- How Angels Act on Bodies
- The Action of the Angels on Man
- The Mission of the Angels
- Of the Guardianship of the Good Angels
- Of the Assaults of the Demons
- Of the Action of the Corporeal Creature
- On Fate
- Of Things Pertaining to the Action of Man
- Of the Production of Man from Man As to the Soul
- Of the Propagation of Man As to the Body

ST.I.1 The Nature and Extent of Sacred Doctrine

To place our purpose within proper limits, we first endeavor to investigate the nature and extent of this sacred doctrine. Concerning this there are ten points of inquiry:

- Whether it is necessary?
- Whether it is a science?
- Whether it is one or many?
- Whether it is speculative or practical?
- How it is compared with other sciences?
- Whether it is the same as wisdom?
- Whether God is its subject-matter?
- Whether it is a matter of argument?
- Whether it rightly employs metaphors and similes?
- Whether the Sacred Scripture of this doctrine may be expounded in different senses?

Summa Theologica I.1.1

Whether, besides Philosophy, any Further Doctrine Is Required?

Objection 1: It seems that, besides philosophical science, we have no need of any further knowledge. For man should not seek to know what is above reason: “Seek not the things that are too high for thee” (Ecclus. 3:22). But whatever is not above reason is fully treated of in philosophical science. Therefore any other knowledge besides philosophical science is superfluous.

Obj. 2: Further, knowledge can be concerned only with being, for nothing can be known, save what is true; and all that is, is true. But everything that is, is treated of in philosophical science — even God Himself; so that there is a part of philosophy called theology, or the divine science, as Aristotle has proved (Metaph. vi). Therefore, besides philosophical science, there is no need of any further knowledge.

On the contrary, It is written (2 Tim. 3:16): “All Scripture inspired of God is profitable to teach, to reprove, to correct, to instruct in justice.” Now Scripture, inspired of God, is no part of philosophical science, which has been built up by human reason. Therefore it is useful that besides philosophical science, there should be other knowledge, i.e. inspired of God.

I answer that,, It was necessary for man’s salvation that there should be a knowledge revealed by God besides philosophical science built up by human reason. Firstly, indeed, because man is directed to God, as to an end that surpasses the grasp of his reason: “The eye hath not seen, O God, besides Thee, what things Thou hast prepared for them that wait for Thee” (Isa. 66:4). But the end must first be known by men who are to direct their thoughts and actions to the end. Hence it was necessary for the salvation of man that certain truths which exceed human reason should be made known to him by divine revelation. Even as regards those truths about God which human reason could have discovered, it was necessary that man should be taught by a divine revelation; because the truth about God such as reason could discover, would only be known by a few, and that after a long time, and with the admixture of many errors. Whereas man’s whole salvation, which is in God, depends upon the knowledge of this truth. Therefore, in order that the salvation of men might be brought about more fitly and more surely, it was necessary that they should be taught divine truths by divine revelation. It was therefore necessary that besides philosophical science built up by reason, there should be a sacred science learned through revelation.

Reply Obj. 1: Although those things which are beyond man’s knowledge may not be sought for by man through his reason, nevertheless, once they are revealed by God, they must be accepted by faith. Hence the sacred text continues, “For many things are shown to thee above the understanding of man” (Ecclus. 3:25). And in this, the sacred science consists.

Reply Obj. 2: Sciences are differentiated according to the various means through which knowledge is obtained. For the astronomer and the physicist both may prove the same conclusion: that the earth, for instance, is round: the astronomer by means of mathematics (i.e. abstracting from matter), but the physicist by means of matter itself. Hence there is no reason why those things which may be learned from philosophical science, so far as they can be known by natural reason, may not also be taught us by another science so far as they fall within revelation. Hence theology included in sacred doctrine differs in kind from that theology which is part of philosophy.

Summa Theologica I.1.2

Whether Sacred Doctrine Is a Science?

Objection 1: It seems that sacred doctrine is not a science. For every science proceeds from self-evident principles. But sacred doctrine proceeds from articles of faith which are not self-evident, since their truth is not admitted by all: “For all men have not faith” (2 Thess. 3:2). Therefore sacred doctrine is not a science.

Obj. 2: Further, no science deals with individual facts. But this sacred science treats of individual facts, such as the deeds of Abraham, Isaac and Jacob and such like. Therefore sacred doctrine is not a science.

On the contrary, Augustine says (De Trin. xiv, 1) “to this science alone belongs that whereby saving faith is begotten, nourished, protected and strengthened.” But this can be said of no science except sacred doctrine. Therefore sacred doctrine is a science.

I answer that,, Sacred doctrine is a science. We must bear in mind that there are two kinds of sciences. There are some which proceed from a principle known by the natural light of intelligence, such as arithmetic and geometry and the like. There are some which proceed from principles known by the light of a higher science: thus the science of perspective proceeds from principles established by geometry, and music from principles established by arithmetic. So it is that sacred doctrine is a science because it proceeds from principles established by the light of a higher science, namely, the science of God and the blessed. Hence, just as the musician accepts on authority the principles taught him by the mathematician, so sacred science is established on principles revealed by God.

Reply Obj. 1: The principles of any science are either in themselves self-evident, or reducible to the conclusions of a higher science; and such, as we have said, are the principles of sacred doctrine.

Reply Obj. 2: Individual facts are treated of in sacred doctrine, not because it is concerned with them principally, but they are introduced rather both as examples to be followed in our lives (as in moral sciences) and in order to establish the authority of those men through whom the divine revelation, on which this sacred scripture or doctrine is based, has come down to us.

Summa Theologica I.1.3

Whether Sacred Doctrine Is One Science?

Objection 1: It seems that sacred doctrine is not one science; for according to the Philosopher (Poster. i) “that science is one which treats only of one class of subjects.” But the creator and the creature, both of whom are treated of in sacred doctrine, cannot be grouped together under one class of subjects. Therefore sacred doctrine is not one science.

Obj. 2: Further, in sacred doctrine we treat of angels, corporeal creatures and human morality. But these belong to separate philosophical sciences. Therefore sacred doctrine cannot be one science.

On the contrary, Holy Scripture speaks of it as one science: “Wisdom gave him the knowledge of holy things” (Wis. 10:10).

I answer that,, Sacred doctrine is one science. The unity of a faculty or habit is to be gauged by its object, not indeed, in its material aspect, but as regards the precise formality under which it is an object. For example, man, ass, stone agree in the one precise formality of being colored; and color is the formal object of sight. Therefore, because Sacred Scripture considers things precisely under the formality of being divinely revealed, whatever has been divinely revealed possesses the one precise formality of the object of this science; and therefore is included under sacred doctrine as under one science.

Reply Obj. 1: Sacred doctrine does not treat of God and creatures equally, but of God primarily, and of creatures only so far as they are referable to God as their beginning or end. Hence the unity of this science is not impaired.

Reply Obj. 2: Nothing prevents inferior faculties or habits from being differentiated by something which falls under a higher faculty or habit as well; because the higher faculty or habit regards the object in its more universal formality, as the object of the common sense is whatever affects the senses, including, therefore, whatever is visible or audible. Hence the common sense, although one faculty, extends to all the objects of the five senses. Similarly, objects which are the subject-matter of different philosophical sciences can yet be treated of by this one single sacred science under one aspect precisely so far as they can be included in revelation. So that in this way, sacred doctrine bears, as it were, the stamp of the divine science which is one and simple, yet extends to everything.

Summa Theologica I.1.4

Whether Sacred Doctrine Is a Practical Science?

Objection 1: It seems that sacred doctrine is a practical science; for a practical science is that which ends in action according to the Philosopher (Metaph. ii). But sacred doctrine is ordained to action: “Be ye doers of the word, and not hearers only” (James 1:22). Therefore sacred doctrine is a practical science.

Obj. 2: Further, sacred doctrine is divided into the Old and the New Law. But law implies a moral science which is a practical science. Therefore sacred doctrine is a practical science.

On the contrary, Every practical science is concerned with human operations; as moral science is concerned with human acts, and architecture with buildings. But sacred doctrine is chiefly concerned with God, whose handiwork is especially man. Therefore it is not a practical but a speculative science.

I answer that,, Sacred doctrine, being one, extends to things which belong to different philosophical sciences because it considers in each the same formal aspect, namely, so far as they can be known through divine revelation. Hence, although among the philosophical sciences one is speculative and another practical, nevertheless sacred doctrine includes both; as God, by one and the same science, knows both Himself and His works. Still, it is speculative rather than practical because it is more concerned with divine things than with human acts; though it does treat even of these latter, inasmuch as man is ordained by them to the perfect knowledge of God in which consists eternal bliss. This is a sufficient answer to the Objections.

Summa Theologica I.1.5

Whether Sacred Doctrine Is Nobler than Other Sciences?

Objection 1: It seems that sacred doctrine is not nobler than other sciences; for the nobility of a science depends on the certitude it establishes. But other sciences, the principles of which cannot be doubted, seem to be more certain than sacred doctrine; for its principles — namely, articles of faith — can be doubted. Therefore other sciences seem to be nobler.

Obj. 2: Further, it is the sign of a lower science to depend upon a higher; as music depends on arithmetic. But sacred doctrine does in a sense depend upon philosophical sciences; for Jerome observes, in his Epistle to Magnus, that “the ancient doctors so enriched their books with the ideas and phrases of the philosophers, that thou knowest not what more to admire in them, their profane erudition or their scriptural learning.” Therefore sacred doctrine is inferior to other sciences.

On the contrary, Other sciences are called the handmaidens of this one: “Wisdom sent her maids to invite to the tower” (Prov. 9:3).

I answer that,, Since this science is partly speculative and partly practical, it transcends all others speculative and practical. Now one speculative science is said to be nobler than another, either by reason of its greater certitude, or by reason of the higher worth of its subject-matter. In both these respects this science surpasses other speculative sciences; in point of greater certitude, because other sciences derive their certitude from the natural light of human reason, which can err; whereas this derives its certitude from the light of divine knowledge, which cannot be misled: in point of the higher worth of its subject-matter because this science treats chiefly of those things which by their sublimity transcend human reason; while other sciences consider only those things which are within reason’s grasp. Of the practical sciences, that one is nobler which is ordained to a further purpose, as political science is nobler than military science; for the good of the army is directed to the good of the State. But the purpose of this science, in so far as it is practical, is eternal bliss; to which as to an ultimate end the purposes of every practical science are directed. Hence it is clear that from every standpoint, it is nobler than other sciences.

Reply Obj. 1: It may well happen that what is in itself the more certain may seem to us the less certain on account of the weakness of our intelligence, “which is dazzled by the clearest objects of nature; as the owl is dazzled by the light of the sun” (Metaph. ii, lect. i). Hence the fact that some happen to doubt about articles of faith is not due to the uncertain nature of the truths, but to the weakness of human intelligence; yet the slenderest knowledge that may be obtained of the highest things is more desirable than the most certain knowledge obtained of lesser things, as is said in de Animalibus xi.

Reply Obj. 2: This science can in a sense depend upon the philosophical sciences, not as though it stood in need of them, but only in order to make its teaching clearer. For it accepts its principles not from other sciences, but immediately from God, by revelation. Therefore it does not depend upon other sciences as upon the higher, but makes use of them as of the lesser, and as handmaidens: even so the master sciences make use of the sciences that supply their materials, as political of military science. That it thus uses them is not due to its own defect or insufficiency, but to the defect of our intelligence, which is more easily led by what is known through natural reason (from which proceed the other sciences) to that which is above reason, such as are the teachings of this science.

Summa Theologica I.1.6

Whether This Doctrine Is the Same as Wisdom?

Objection 1: It seems that this doctrine is not the same as wisdom. For no doctrine which borrows its principles is worthy of the name of wisdom; seeing that the wise man directs, and is not directed (Metaph. i). But this doctrine borrows its principles. Therefore this science is not wisdom.

Obj. 2: Further, it is a part of wisdom to prove the principles of other sciences. Hence it is called the chief of sciences, as is clear in Ethic. vi. But this doctrine does not prove the principles of other sciences. Therefore it is not the same as wisdom.

Obj. 3: Further, this doctrine is acquired by study, whereas wisdom is acquired by God’s inspiration; so that it is numbered among the gifts of the Holy Spirit (Isa. 11:2). Therefore this doctrine is not the same as wisdom.



Mr. William C. Michael is the founding headmaster of the <a href=”">Classical Liberal Arts Academy</a>. He graduated from Rutge

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
William C. Michael

Mr. William C. Michael is the founding headmaster of the <a href=”">Classical Liberal Arts Academy</a>. He graduated from Rutge