Introductory.

1. NATURAL THEOLOGY is the science of God, so far as God can be known by the light of our reason alone. In order to make the meaning of this definition clear, we have first to explain what we understand by Theology; then what signification we attach to the compound term Natural Theology; and finally, what right we have to call Natural Theology a science.

First, then, as regards the word Theology. It is derived from two Greek nouns, theos and logos, and means literally speaking or reasoning about God. In this sense the word occurs in both Plato and Aristotle.^{1} By Natural Theology is meant that kind of reasoning about God, which starts from principles, the truth of which can be known to us by the light of our natural reason left to itself, that is, to its innate capacity of perceiving and judging the facts as well of common as of scientific experience, and of drawing conclusions from these facts according to principles that either are self-evident or have previously been proved. If this reasoning is carried on systematically, it results, as we shall discover, in a system of truths about God, the First Cause of all things, and may therefore be rightly called the Science of Natural Theology.

It is the object of this science to vindicate the existence and honour of the one true God against the denial of Atheists, the doubts of Agnostics, the misrepresentations of Pantheists, and the absurdities of Polytheists.

2. There is another system of truths regarding Almighty God which is called Supernatural, or more commonly, Dogmatic Theology. Between this and Natural Theology there is a wide difference.

(1) In the first place they differ in their foundation. For whereas Natural Theology is based upon principles known by reason with human certainty, Supernatural Theology has for its foundation principles accepted by faith which rests on the authority of God Himself, who has declared them to us by Divine revelation.

(2) From this difference there results another regarding the method of demonstration used in the two sciences. Natural Theology draws its arguments from the intuitions of reason and from facts of experience; Supernatural Theology finds the premisses of its conclusions in the sources of Christian Revelation, which are the Canonical Scriptures and the documents of Divine Tradition.

(3) Finally there is a vast difference between the achievements of the one and the other. Natural Theology inquires into the existence, the attributes, and works of the one infinite God, without being able to treat of the inscrutable mysteries of the Blessed Trinity and of the Word Incarnate; whereas Supernatural Theology, although it does not pretend to make these mysteries comprehensible to reason, yet, guided by Divine revelation, which has established their reality, analyzes their meaning, shows their consequences, illustrates their harmony with known truths, and thus throws light upon the Divine beauty of Christian Revelation.

Hence we see that the chief subject-matter of which Natural and Supernatural Theology treat, is the same; but the aspect, under which they view it, is altogether different, or to express this in the language of the schoolmen, Natural and Supernatural Theology agree to a large extent in their material object, but they differ in their formal object.

3. The very nature of Supernatural or Dogmatic Theology implies and demands that Natural Theology should precede it and prepare its way. For it is the duty of reason to prepare the minds of men for the acceptance of Divine revelation, upon which Dogmatic Theology is built. Before an infidel can reasonably feel obliged to acknowledge a creed as Divine, he must be convinced that there is a God, who can communicate truths to men, and that men can accept these truths without danger of deception. It is Natural Theology that opens the way to this. conviction by strict logical reasoning. Christian Doctors therefore rightly call the truths developed in Natural Theology the praeambula fidei; and the office assigned to Philosophy in general, when it is. called the handmaid of (Dogmatic) Theology, belongs especially to the particular branch of Philosophy now under consideration.

We may add that Dogmatic Theology taught under the supervision of the Infallible Church, is for the Catholic philosopher a guiding-star even to his philosophical reasonings about God. This is a most sound and intelligible proposition, but it is one peculiarly liable to misrepresentation. We are far from claiming the right to draw the course of philosophical reasoning away from its natural paths in order to bring the results into fictitious conformity with those of revelation. Such a procedure would be as foolish as it would be dishonest. Our claim is to imitate the mariner to whom the star is a guiding-star, not because it dispenses him from the due use of the compass, but because it enables him to check the errors into which he may have fallen in his estimate of the records of the needle. The Catholic philosopher is conscious that human reason, particularly when it embarks on the difficult sea of philosophical speculations, is liable to go astray through defective observance of its own laws. On the other hand he has sure grounds for his conviction that the Church's teaching is absolutely reliable. What more reasonable than that on finding a discrepancy between the results of his philosophical reasoning and his Dogmatic Creed, he should conclude the former to be in some point defective and should retrace his steps to discover where the defect may lie?

4. In what we have said about the standpoint of a Catholic writer on Natural Theology, we cannot reasonably expect to be fully understood by those outside the Church. All that we ask for from non-Catholic readers is to judge our conclusions in Natural Theology by the light of principles which must be admitted by every reasonable man. Let them consider whether we ever make an undue use of authority to establish a truth which should be proved by reason alone; let them judge for themselves whether we meet our adversaries with solid arguments or with empty phrases, and whether we enunciate any opinion which is out of harmony with well-established scientific facts.

5. Approaching our subject in this spirit, we have a reasonable claim to the sympathy and interest of our readers. For what subject of inquiry can be compared with the first source of all things, the Infinite Majesty of God? Moreover, if as reasonable beings we are irresistibly drawn to inquire into the causes of things, must not all our researches suffer from want of solidity and completeness, if we lack a true knowledge of God, the First Cause, of all things, and of His relation to this world? Such knowledge throws light upon the origin of the universe, upon the nature and destiny of man, upon the true meaning of life, upon our duties here on earth, upon our prospects for the future, upon the wonders as well as the woes of human history. Nay, there is no department of knowledge which is not ennobled when viewed in the light of these truths: because from God, and through Him, and in Him, are all subjects that can possibly have a claim on man's attention.

What makes this study still more important is that without it we cannot hope truly to estimate and solidly to refute the charges brought forward against the reasonableness of Christian faith by atheists, agnostics, and pantheists, who know well how to support their statements with an array of specious arguments. If we wish to diminish the harm inevitably caused by the spreading of such false opinions, we must be able to produce a good store of arguments by which the existence of God, His attributes, and His relation to this world are proved, in such a way, that their force may come home to the mind of every one who does not obstinately prefer darkness to light.

For some of our readers it may be useful to call attention to the danger of resting content with a partial knowledge of our subject, or thinking that a thorough grasp of it can be obtained without patient study. Beginners who have not perseverance enough to reason step by step, but who pick out one question or another at random, must not wonder if they very soon find themselves hopelessly confused, and utterly unable either duly to appreciate or clearly to solve the difficulties of adversaries.

6. The order of our discussion is suggested by the three following questions:

I. Can we know for certain that there exists One first intelligent and infinitely perfect Cause of all things, that is to say, One personal God of infinite perfection, Creator of the world?

II. Granted that there exists One personal God of infinite perfection, what are the special attributes of this One infinite Being?

III. If there be such a personal God, what can we know about His action upon this world?

Following the line of thought suggested by these three questions, we shall divide our treatise into three books: the first treating of the existence of God, the second of the attributes of God, the third of the influence which God exercises upon this world.

{1} Plato (Republ. 379 A) speaks of of hoi tupoi peri theologias, meaning the forms in which tales about gods should be shaped. Aristotle (Meteorolog. Lib. II. c. i.) gives us the opinion of hoi diatribontes peri tas theologias on the sources of the ocean. He refers to the old poets, Orpheus, Hesiod, Homer, and their fables about the gods. St. Thomas, in his commentaries on Aristotle, calls them the poetae theologi; by Aristotle himself they are styled hoi theologoi. (Metaph. Lib. XI. al. XII. c. vi.) According to Max Müller, Theos, Deus, is connected with the Sanscrit Deva, signifying "the Brilliant," a very suggestive denomination of the Supreme Being who, according to St. Paul, dwells in light inaccessible (1 Tim. vi. 16), and according to St. John. is "Light" (St. John i. 5). (Cf. M. Müller, Science of Language. second Series, pp. 405, 449, and Science of Religion, p. 269.)