As I have cleared my way, -- first of all, by answering the complaints and accusations brought against the Philosophy of the School, and then by afterwards pointing out the general or special difficulties which may beset the path of a student who is proposing to himself to enter upon the study of Metaphysics; -- it remains for me now to explain the intention, plan, sources, and divisions of the present Work.

The title of the Book sufficiently explains its aim and purport. It does not pretend to be a new, or original philosophy. Of these we have (if I mistake not) quite enough already. It professes simply to give in English, to the best of the author's ability, the fundamental Philosophy of the School, which will be found to differ little, if at all, from that of Aristotle, -- a philosophy which goes by the name of the Peripatetic. But two obstacles to the accomplishment of my purpose presented themselves. It is well known that among the medieval Scholastics there were rival Schools of philosophy. To begin with, -- there were the Nominalists, the Realists, and the Conceptualists, mutually opposed on the question of Universals. These, of course, would not trouble us much in Metaphysics; since the subject of their disputings properly belongs to Ideology. But, besides these, there were the rival Schools of the Scotists, of the Thomists, and of the Augustinians. It would have been impossible to introduce the points of difference between these different Schools, without unreasonably adding to the bulk of the Work, already extending itself to four Volumes. Then, again, if it had been otherwise expedient, there was one palmary reason why it should not be attempted. For it would have certainly created inextricable confusion in the mind of a beginner; while it would have uselessly distracted his attention from those fundamental principles on which all the Schoolmen, morally speaking, are agreed. Moreover, many of these disputed questions are philosophico-Theological; that is to say, they are Theological problems which include a philosophical problem. But these would be excluded from the present Work by reason of their quality; since it is neither in harmony with my purpose nor with the title of the Book, to allow of any digressions into supernatural Theology. Lastly, many of these disputed questions are of comparatively minor importance; and may be safely left to the after study of such as are willing to pursue their investigations. Nevertheless, there are certain questions, at once philosophical and of great moment, wherein there is a marked dissidence of teaching in rival Schools. How then was I to represent the teaching of one School to the exclusion of another, without making myself the arbiter, and furthermore identifying the Scholastic teaching, as a whole, with that of a mere section? This was the first difficulty which, as it seemed to me, I had to encounter in the prosecution of my purpose.

Another obstacle arose out of the fact, that the medieval Doctors have not written express treatises on Metaphysics. I cannot call to mind one of them who has left behind him anything that can claim the name. The fact is, that they had other work to do. They were fully occupied with a scientific evolution and a scientific construction (i.e. construction in scientific form) of the Christian Faith and Revelation; and, therefore, they were wont to discuss metaphysical truths, here and there, as these chanced to present themselves in connection with, or relation to, Christian dogmas. It is true (as I have had occasion to remark already) in the writings of St. Thomas, -- the Angelic Doctor, -- we find Commentaries on the Metaphysics, as on most of the other Works, of Aristotle; and several Opuscula which are exclusively devoted to subjects of Philosophy. Thus, for instance, in the forty-eighth (otherwise, the forty-fourth) Opusculum, we find an exposition of the entire Logic of Aristotle. The forty-second (otherwise, the thirty-ninth) treats of the nature of Genus; the forty-third (otherwise, the fortieth), of the powers, or faculties, of the Soul; the forty-fourth (otherwise, the forty-first), of Time; the thirty-second (otherwise, the twenty-eighth), of the nature of Matter and indeterminate Dimensions; and so on. But these Opuscula, -- most valuable, as they certainly are, -- have neither unity of order nor methodical combination. They would appear to have been independent tracts, -- some of them, mere notes for Lecture, others, again, written for the benefit of some individual student who was in the meshes of a difficulty, -- all written for a particular occasion, or with a particular purpose, or to satisfy a temporary want. From this desultory (if I may so call it) and subsidiary treatment of metaphysical questions, one great advantage accrues; viz, that we are thus enabled to gather the mind of St. Thomas with the greater certainty and clearness. For, as he is on this account led to treat the same subject over and over again in his writings, -- considering it now in its relation to one, now in relation to another, of the Christian dogmas, -- at another time, (it may be), as it is in its own essential nature, independently of its connection with other truths; we are enabled to look round his teaching on the given point, and to substitute that which is clear and certain in one passage for that which may be obscure and doubtful elsewhere. Nevertheless, the reduction of this copious body of doctrine into a methodical whole must be done by the student for himself.

The Scholastic Doctors who flourished after the Council of Trent, -- now that the work of scientific evolution had reached its maturity, -- were enabled to turn their attention to the construction of an ordered treatise on Metaphysics. Accordingly, such treatises began to appear, and remain to this day. Conspicuous among these is the exhaustive Work of Suarez, which has been of the greatest service to myself in the construction of the intended Volumes; for it has not only reduced the digressive and somewhat unmethodical Metaphysics of Aristotle to an order that harmonizes with his own Disputatious, (as he calls them), but it at the same time supplies us with a scientific development of truths, and a division of the subject-matter, which materially lessen the difficulty of construction. There is, however, a considerable drawback. For, since Suarez, (as he tells us himself in the Preface), wrote his Metaphysics with an eye to supernatural Theology, and for the purpose of supplying the Theological student beforehand with that knowledge of philosophy which was necessary to the successful prosecution of his studies; he has discussed the problems of natural Theology, here and there, in common with those of finite Being, instead of reserving the former for separate treatment. It may be that he was moved to the selection of this method, by the consideration that the student would have all these Theological truths again set before him, collected under one conspectus in the Treatise of supernatural Theology on the One God. Or he may have adopted it, because he deemed it a more logical arrangement and easier for purposes of instruction. Whatever the case may have been; the fact added another difficulty in the way of my attempt.

I will now let the reader know in what way I have encountered these difficulties. I determined to assume the general order, method, and divisions of Suarez, as the logical basis of my Work; reserving to myself the full liberty of introducing a change here or there, if it should seem better suited to my purpose. The following, then, is the principal division. I propose that the entire Work should consist of nine Books. The first treats of the Definition of Metaphysics; the second, of Being; the third, of the Transcendental Attributes of Being. These three Rooks complete the present Volume, In the fourth Book will be considered the Principles of Being; in the fifth, the Causes of Being; in the sixth, the primary Determinations of Being; in the seventh and eighth, the Categories of Aristotle; in the ninth, natural Theology. So much for the skeleton. But this, though a serious, was by no means the most serious, difficulty. It remains for me now to explain, how I have attempted to meet the greater difficulties touching a discriminate selection of the questions proposed for discussion.

First of all, then, I have omitted most, if not all, of what may be called subordinate questions which, however interesting in themselves and sometimes fertile in thought, might only perplex and weary the beginner. By so doing I secure another advantage; because, for the most part, it is precisely these questions which form the battle-field of contending Schools. I have likewise scrupulously avoided such discussions as are connected with supernatural Theology. I will not shrink from the expression of a conviction, that the Metaphysics of the School does incline the mind towards a belief in the Catholic Creed, not only by helping to remove intellectual difficulties, but likewise by bringing out into strong relief the harmony that exists between the highest truths in the natural, and those in the supernatural, order. This, however, is no fault of mine. Truth must everywhere be one, because it proceeds from One. But these two orders of truth are perfectly distinct in themselves. The one rests upon Divine authority; the other is discoverable by pure process of unassisted reason, (that is to say of reason supernaturally unassisted). It is with the latter, and with the latter only, that the metaphysical Science concerns itself. I should, therefore, consider that I was betraying the confidence of my readers if I did not scrupulously exclude from these pages, (save occasionally, for the mere purpose of illustration), all discussion or consideration of the former order of truths.

This determination secures me, again, from the necessity of entering upon many minor questions which are subjects of controversy in the Schools. But there still remained the obligation of choosing from among the different Schools that one in particular which might be considered as representative, more than any other, of the Scholastic teaching. Here, however, I found but little difficulty. No one, who has any knowledge of the history of Scholasticism, can be ignorant of the paramount influence which the writings of St. Thomas of Aquino have exercised over the Schools from his time up to now. The Summa of that great Doctor very soon became the general text-book, supplanting the Sentences of Peter Lombard. Most of the religious Orders, which were chosen by God to be the principal repositories of the higher branches of knowledge, -- the Benedictines, Augustinians, Carmelites, -- in their rules and constitutions commanded their subjects to study the teaching of St. Thomas and religiously adhere to it. I need not mention the illustrious Order of St. Dominic, which can justly boast of having given to the Church and to the world this paragon of wisdom.

But I may not omit a special reference to that Order to which I belong, -- the Society of Jesus. It tells its members, and particularly its professors of Scholastic Theology, that 'Ours are to follow entirely in Scholastic Theology the teaching of St. Thomas, and to consider him as their own Doctor: and they are to use their utmost exertions to render those that follow their Lectures as well disposed towards him as possible.' It cautions its Professors of Philosophy 'not to speak of St. Thomas otherwise than with praise, following him with a willing mind as often as it behoves; or with reverence and gravity forsaking him, if occasionally he should not be quite so acceptable.' He who has charge and supreme supervision in these matters is thus admonished: 'Let him above all things bear in mind, that those who are not well affected towards St. Thomas are not to be promoted to the Chairs of Theology; and that they who are averse to him, or are even not sufficiently given to the study of him, are to be debarred from the office of teaching.' It is evident, then, how entirely the Society of Jesus has accepted the teaching of St. Thomas as her own in supernatural Theology alike and in Philosophy. That these directions have been carried out in her Schools, is sufficiently patent from the fact that the works of her most celebrated Scholastic Theologians, with scarcely an exception, are commentaries on the Summa of St. Thomas; while her philosophical teaching according to her rules, must be based on that of Aristotle and on the doctrine of the Angelic Doctor.

Add to this testimony of the religious Orders the yet weightier witness of the Catholic Church. Not only have the writings of the Angelic Doctor been frequently extolled with highest praises by successive Popes; but their study has been repeatedly commended, or rather enjoined, by the same authority, on the Universities and Colleges. I will add one more fact which speaks volumes, In the Sessions of the Council of Trent the Summa of St. Thomas was placed in the midst of the conclave on the altar, together with the Sacred Scriptures and the Papal Decrees; -- an honour and tribute of praise which, as Leo XIII points out,^{1} had never before been offered to any Doctor the Church.

I think, then, that I had sufficient reason for my selection. Nor must I omit the confession that, in doing so, I was following likewise the bent of my own tastes and the conclusion of my own judgment. For many years I have been more or less occupied in study of St. Thomas; and increasing acquaintance has only served to strengthen that admiration for his genius and that veneration for his doctrine and authority, which conquered me from the first. His writings, in one respect, bear a great resemblance to the sacred Scriptures. I refer to the wonderful fecundity of thought discoverable in the briefest passages; so that, as you read them over and over again and ponder over them, fresh ideas are awakened, new revelations of truth are made. There is not a philosophical problem that has risen up in our own day, so far as I have had an opportunity of observing, which does not meet with a satisfactory solution in his pages. Nay, even within the sphere of Physics, where he lay under peculiar disadvantage by reason of the imperfect knowledge then existing concerning such subjects, he almost seems to have forestalled, in the principles which he has given for our guidance, the latest discoveries that have been made. This at all events can be safely said, -- and I hope to be able to convince the reader, in my second Volume, of the truth of the assertion, -- that his teaching with regard to the genesis of the material universe, the primordial constituents of bodies, and the generation of man, harmonizes wonderfully with the inductions of modern experimentalists.

I ought not to omit another characteristic of St. Thomas, -- his admiration and (it is not too much to say) his reverence for Aristotle as a philosopher. His moral Theology -- to repeat what I have said before -- is built upon the Ethics of the grand Stagyrite; just as the morality of the Gospel is based on the natural Law. He rarely, if ever, determines a problem in philosophy, without summoning the authority of the Greek Philosopher to his support; and whenever he quotes him, it is always by the distinctive title of the Philosopher. To my mind, it is impossible to separate the two in our estimate of the great leaders of thought that have been given to us since the commencement of the historic period. They stand absolutely alone; -- the one the giant of the old world, the other the giant of the new. Whether we look to the universality of their genius which seems to have embraced every subject that is knowable by man, -- or to their profundity of thought, -- or to their practical common sense and prudence of judgment, -- or to the influence that their writings have exercised and continue to exercise on their fellow-men, -- they are unrivalled. As is right and fitting, the style of the two is so exactly similar, that one might, without exaggeration, pronounce it to he identical. Terseness of expression, that great mark of intellectual grasp, -- a simplicity that is so entirely stripped of ornament as to be almost bald, -- a chariness in the use of hard words and technical phrases, -- short, pithy, sentences, -- admirable precision; such are the characteristics of St. Thomas, as of Aristotle. Equally remarkable are they both in their power of mental grasp. They do not nibble at a truth, as men of inferior make so often do. On the contrary, they contemplate it from every side, -- realize its proportion, bearings, multiplex relations, -- separate it from all that exhibits a likeness to it but is not really of it, -- clearly comprehend its fulness at once and its limits; -- sift that which is essential from what is merely adventitious ; -- and all this, as if by intuition. Hence it will be often found that, by a single word or a simple distinction, they will throw a flood of light on the particular object of contemplation, and will extricate it from a network of difficulties in which, at first sight, it seemed to be hopelessly entangled.

But this singular power of comprehension in the teacher not unfrequently puts the student at a disadvantage, more especially at the commencement of his apprenticeship. I here allude in particular to the Angelic Doctor; and shall take him as the instance of what I mean. Since, then, St. Thomas retained an intimate, ever-present, vision of the varied and often mutually discrepant connection of each truth with those that surround it; it constantly bappens that he represents a given truth now under one relation, now under another. In themselves, these representations xvill be independent of each other; sometimes, even discrepant; though to the intuition of their author they are indissolubly connected. Hence it comes to pass, that the doctrine in one passage seems to be at open war with the doctrine in another. The reader can at once convince himself of the fact, by consulting the Index, or Tabula Aurea, which is commonly subjoined to the complete Works of St. Thomas. He will find there, in alphabetical order, a summary statement of the teaching of this great Doctor on any given question with a list of references. Immediately after, (some times as often as three or four times in a single page), his eyes will fall on the oft-repeated sentence, He seems to say the opposite, followed by another list of references. It is needless to observe, that there is no real opposition. A careful collation of the two series of quotations will not only serve to reconcile the apparent contradiction, but will result in the acquiring of a more accurate and more comprehensive cognition of the truth explained. In order, however, to be capable of conducting such an investigation with success, we must possess an intimate acquaintance with the mind and writings of St. Thomas; and, at first, we must rest satisfied to have the work done for us by others. Yet, as no one can become an adept in the Scholastic Philosophy or can hope to secure to himself the deep truths which are contained therein, unless he is familiar with the writings of the Angelic Doctor; I have done my best to assist the reader in this direction, not only by copious quotations, but likewise by giving the original at the foot of the page. By comparing the translation with the Latin text, it seemed to me that a beginner might soon accustom himself to the style and mind of St. Thomas, with comparatively little cost of labour. When once he has accomplished this, his way is plain before him; if he wills to work.

As soon as I had determined upon constructing the present treatise upon the model of Suarez' Metaphysics, the difficulty of reducing the philosophical teaching of the Angelic Doctor into one proportioned whole well-nigh disappeared; since it only remained for me to collect under certain heads, corresponding with my contemplated division, those passages in his different Works which dealt with the respective subjects of discussion. I would that some one might be found, able and willing to perfect such arrangement; and thus to give to the world a complete Metaphysics of St. Thomas, (composed entirely of passages collected from his writings), in an English dress. I feel sure that it would be generally hailed, by men of thought, as a great boon. In the mean time, I have done my best to contribute towards this desirable result; so far as it was consonant with the professed purpose of this work to do so.

One other difficulty has been mentioned above, -- the hardest with which I have had to deal. Owing to reasons which have been already explained, it is not always easy to determine the meaning of St. Thomas; and, accordingly, Doctors, who sincerely profess to follow with equal devotion the teaching of the Angelic Doctor, differ at times in the interpretation of his words, -- sometimes on questions of no ordinary importance. Such divergence is more observable within the sphere of Scholastic Theology, perhaps, than within that of Philosophy. Still, even here, there are a few very grave problems which, according to the Dominican, or Thomist, School, are solved by St. Thomas in one way, but, according to the Jesuit School, are solved by St. Thomas in another way; while each declares that it represents the true mind of this Doctor. It was, in fact, one of these questions that excited the uninstructed wonder, and disturbed the equanimity, of Hobbes; -- the only one, moreover, so far as I can foresee at present, that will claim consideration in these Volumes. It might naturally be supposed that I should adopt the teaching and the interpretation of St. Thomas, which have been defended by the Order to which I belong. But, while admitting the justice of the supposition, I can sincerely aver, that the primary motive which has induced me to defend the one and the other has been the greater weight of intrinsic evidence that, as it seemed to me, can be produced in their favour. Nevertheless, to err is human; and it can hardly be denied, that an interpretation of St. Thomas, which is commended to us by an authority so grave as that of the justly renowned Order of St. Dominic, must carry with it an extrinsic evidence second to none. Wherefore, when the proper occasion offers, I will do my best to put the reader folly in possession of the two opinions, together with the reasons that have been adduced in support of each; leaving him to select for himself the one which may seem, in his judgment, to be more conformable with the truth.

So much for the matter of the present Work: I have now to add a word or two touching what may be called its form. I can easily imagine that a complaint may be urged against the length of my Treatise. It is a proverb, which the men of our time are not likely to forget, that a big book is a big evil. The taste prevailing at present favours compendiums, summaries, Pinnock's catechisms, et id genus omne, on all graver subjects of reading. There seems be a general impression that mental labour, like manual work, may be done more expeditiously by a simplification of force. But I do not think that even the mechanist has ever dreamt of reducing human labour, by subtracting from the necessary material. It is reported, indeed, of one of the Pharaohs, that he ventured on the experiment; but the unfortunate Hebrew workmen did not find that it lightened their work. For a like reason I confess to a settled aversion for compendiums and all abbreviations of whatsoever kind, more particularly in the higher and nobler spheres of knowledge. It seems to me, that they inflate rather than inform; or, if they impart knowledge, it is that little knowledge which, as we are told, is so dangerous a thing. But, when admitted into Philosophy and Theology, their results are the more disastrous, in proportion to the excellence and dignity of the subject-matter. It will be a happy day in the interests of truth, when such ware is relegated to the second-hand book-stalls of our hack streets. I saw lately a letter in one of our newspapers, wherein the writer, (evidently anxious to acquire some knowledge of the philosophy of St. Thomas), expressed a desire that some one should publish a Work on this subject in a moderately sized octavo. Why, you might as reasonably hope to lull a giant to sleep in a baby's cradle! One might, indeed, collect the headings of those Articles in which St. Thomas discusses matters of Philosophy, subjoining an answer in the affirmative or negative, as the case might be; but how much more of the Angelic Doctor and his teaching would the reader of such a production know at the end, than he knew at the beginning? No: we must not be content with the mere conclusions, but must painfully labour at the demonstration of each conclusion; unless we would be contented with the humble and unenviable position of an animated index. I am, nevertheless, conscious that a Work on Metaphysics, which presents itself before the public, (as the present one purports to do), under the form of four portly Volumes, will be not unreasonably regarded as a trespass on the patience of its readers, if these should he forthcoming. But I have something to say for myself, which may possibly mollify the just indignation of my critics; and it is this: no inconsiderable addition has been made to the bulk by a copious use of illustrations. I have known from my own experience that, for beginners in any abstract science, (such as that of Mathematics or Philosophy), nothing helps towards an understanding of the subject so much, as a plentiful use of examples. Minds hitherto accustomed to the contemplation of Truth in the concrete, -- that is to say, so far as it reveals itself to the perceptions of sense, -- are bewildered when first summoned to the contemplation of abstract truths; because they find themselves almost entirely deprived of that aid from sensile phantasmata, -- those material images, impressed upon the inner senses, which had till now guided them along the first pathways of knowledge. Accordingly, it is no small consolation to them, when the place of these phantasmata is, in a measure, supplied by familiar examples taken from the common experience of life. In satisfying this need, moreover, I am but following in the footsteps of Aristotle and St. Thomas, whose writings abound in homely illustrations; though I may have been more prodigal in this respect, because I considered them peculiarly necessary in the present general unprovidedness of even cultivated intellects in this country.

I now proceed to explain the shape into which I have thrown the subject-matter, -- in other words, the didactic method which I have chosen. I could have wished to follow the pattern of St. Thomas, whose manner of treatment has been fully explained in previous pages of this Introduction; but I feared lest, by doing so, I might destroy every chance of securing readers. It seemed to me more than probable, that even those who were otherwise favourably inclined towards the general purpose of the Work, would be scared at finding short sentences, short demonstrations short answers to difficulties, -- stripped of all ornament, -- answer on one page or column to a difficulty on another, with the true resolution of the problem, (sometimes of considerable length), intervening between the two. It would postulate too much of the student, in the actual state of things. He would have to divine the meaning, and fill up for himself all that was implied but not expressed, besides perpetually turning the pages backward and forward in order to connect each solution with its corresponding objection; -- to say nothing of the repelling influence which the all but mathematical strictness and baldness of the style would probably have upon him. Suarez has followed much the same system, but has increased its difficulties. For he ordinarily begins a Disputation by enumerating all the opinions which have been maintained concerning the subject-matter, together with the arguments on which each reposes, and the objections brought against is own chosen solution. He then proceeds to answer the former, while reserving the latter. After this comes his own resolution of the question, with the arguments by which he supports it. Finally, he answers the various objections which have been made, by fautors of the rejected opinions, to his own. As he pursues each step at great length, the answers last named are often separated from the corresponding objections, by an interval of some ten, or even twenty, pages. I judged it better, therefore, to adopt a more recent method which, while substantially preserving the old Scholastic system and order, would obviate the inconveniences which the student might experience in a literal imitation of the latter. Accordingly, I have thrown the matter into the form of Propositions, or Theses; and, at the end of each, I state the objections brought against it, (if any such there be), one by one, together with an answer to each objection which immediately follows after the exposition of the difficulty. The several Books are divided into Chapters, -- the Chapters, for the most part, into Articles, -- and, finally, where the complexity or fulness of the subject under discussion has rendered it necessary, the Article is subdivided into Sections.

In my former Works critics, (in other respects sufficiently friendly), have been rather hard upon me, because I had failed to offer for their convenience a general index. The evident honesty of the complaint was to me a great satisfaction; for it seemed so fully to justify me in my determination to disappoint their desire. There are critics who, as the story runs, make a point of never looking into the Book that they are reviewing, for fear lest this work of supererogation might influence the impartiality of their judgment. There are others of a more scrupulous habit of mind, who are loth to write a review in which not a single passage from the author is to be seen, if only as an embellishment of the pages. So they desiderate an index, by whose aid they may hover over the garden, such as it is; and, plucking a flower from one of the beds, may be ready with their proof that they have really visited the inclosure. Their review is in truth an independent Essay expressive of their own opinions; but they will to throw in occasionally a quotation from the Book which, by a bold stroke of the imagination, they suppose themselves to be reviewing; much after the manner of scientific cooks, who add a spoonful of wine or a pinch of spice, as a crowning glory to their culinary chef-d'oeuvre. But, for myself, I have always mightily relished the wisdom of Swift who, after dealing out his contemptuous banter on Abstracts, Abridgements, Summaries, proceeds to give us his notion of Indexes in this wise: -- 'To this' (use of Abstracts, &c.) 'is nearly related that other modern device of consulting indexes, which is to read books Hebraically, and begin where others usually end. And this is a compendious way of coming to an acquaintance with authors; for authors are to be used like lobsters, you must look for the best meat in the tails, and lay the bodies back again in the dish.'^{2} I should be sorry to inconvenience the powerful body that may be affected by these prepossessions, or to merit their ill-will; but I must own to a disinclination that a Work, which is the fruit of some labour, should be treated somewhat after the manner in which certain books are treated by the superstitious who open them at a chance page, with the expectation of receiving, from the hazard, prophetic knowledge. At all events, such a dressing of the window, (as shopmen term it), is not necessary in the present instance; since the adopted method of dividing the subject-matter renders a recurrence to any particular question extremely easy.

At the request of others in whose judgment I place implicit confidence, a Glossary of Terms has been given at the end of this Volume; to which additions will be made in succeeding Volumes, if they should be deemed necessary. As a rule, whenever I have used a purely Scholastic term, or have felt myself compelled to coin a new word (a very rare occurrence); attention has been called to it at the time, and a full explanation afforded of the meaning. Nevertheless, as these words recur again and again, and the reader an may be glad of a reminder; they are included in the Glossary, together with a reference to the page in which they are explained at length. I must here take occasion to ask those who are familiar with the philosophical literature of the day to excuse me, if they find terms admitted into the said Glossary, which for them are household words. No one who is at all conversant with treatises on Logic of any authority, whether ancient or modern, can fail to know what is meant by Second Intentions. Similarly, those who have read the Works of Sir William Hamilton will have no difficulty in understanding the precise value of the word, Concept. But it have should be remembered that the present Work is principally intended for beginners; to many of whom these words will prove as strange, as some of the purely Scholastic terms may possibly seem to those whose equitable consideration I solicit, In the formation of a Glossary it is better to be too copious than too meagre.

In the quotations from Aristotle I have always followed the Berlin edition of Bekker; in those from St. Thomas, the Roman edition (folio). Unfortunately in arranging the Opuscula of the latter, subsequent editors have not followed the order of this edition; which has caused unnecessary confusion. It will be seen that, whenever I have made a citation from any of these lesser writings, I have given two different numbers. Of these the former refers to the Roman edition; the latter to that of Parma in quarto, which has been completed only within the last ten years.

I am afraid that the reader will find this first Volume somewhat dry and very difficult. It was on this account that I had wished to bring out the first and second Volumes together; but circumstances occurred to hinder me from prosecuting my original design. The second Volume, which will comprise the fourth and fifth Books, includes subjects of more general interest, such as a survey and discussion of the philosophy of Kant, -- an estimate of some of the more important points in the Logic of Sir William Hamilton, -- an elaborate exposition and defence of the Scholastic teaching with regard to the primary constituents of bodies, -- a defence of the principle of causality, with answers to the objections that have been brought against it, -- the doctrine touching efficient and final causation. But it may be a consolation for the reader to know, that an accurate knowledge of that which is contained in the present Volume is a necessary preliminary to the study of these (to him, at least) more interesting questions; and I have every confidence that, in the contemplation of the great Transcendentals, he will come across more important and attractive truths, than he would be led at first sight to imagine.

{1} 'Sed haec maxima est et Thomae propria, nec cum quopiam ex doctoribus catholicis communicata laus, quod Patres Tridentini, in ipso medio coclavi ordini habendo, una cum divinae Scripturae codicibus et Pontificum Maximorum decretis Summam Thomae Aquinatis super altari patere voluerunt, unde consilium, rationes, oracula peterentur.' Epistola Encyclica, Aeterni Patris. Aug. 4, 1879.

{2} A letter to a young poet.