Now it will be admitted that the special sciences take us some distance along the road towards an answer to such questions, inasmuch as the truths established by these sciences, and even the wider hypotheses conceived though not strictly verified in them, furnish us with most valuable data in our investigation of those questions. Similarly the alleged fact of a Divine Revelation cannot be ignored by any man desirous of using all the data available as helps towards their solution. The Revelation embodied in Christianity claims not merely to enlighten us in regard to many ultimate questions which mankind would be able to answer without its assistance, but also to tell us about our destiny some truths of supreme import, which of ourselves we should never have been able to discover. It is obvious, then, that whether a man has been brought up from his infancy to believe in the Christian Revelation or not, his whole outlook on life will be determined very largely by his belief or disbelief in its authenticity and its contents. Similarly, if he be a Confucian, or a Buddhist, or a Mohammedan, his outlook will be in part determined by what he believes of their teachings. Man's conduct in life has undoubtedly many determining influences, but it will hardly be denied that among them the predominant influence is exerted by the views that he holds, the things he believes to be true, concerning his own origin, nature and destiny, as well as the origin, nature and destiny of the universe in which he finds himself. The Germans have an expressive term for that which, in the absence of a more appropriate term, we may translate as a man's world-outlook; they call it his Weltanschauung. Now this world-outlook is formed by each individual for himself from his interpretation of his experience as a whole. It is not unusual to call this world-outlook a man's philosophy of life. If we use the term philosophy in this wide sense it obviously includes whatever light a man may gather from the special sciences, and whatever light he may gather from a divinely revealed religion if he believes in such, as well as the light his own reason may shed upon a [pg 005] special and direct study of those ultimate questions themselves, to which we have just referred. But we mention this wide sense of the term philosophy merely to put it aside; and to state that we use the term in the sense more commonly accepted nowadays, the sense in which it is understood to be distinct from the special sciences on the one side and from supernatural theology or the systematic study of divinely revealed religion on the other. Philosophy is distinct from the special sciences because while the latter seek the proximate, the former seeks the ultimate grounds, reasons and causes of all the facts of human experience. Philosophy is distinct from supernatural theology because while the former uses the unaided power of human reason to study the ultimate questions raised by human experience, the latter uses reason enlightened by Divine Revelation to study the contents of this Revelation in all their bearings on man's life and destiny.
Hence we arrive at this simple and widely accepted definition of philosophy: the science of all things through their ultimate reasons and causes as discovered by the unaided light of human reason.[5] The first part of this definition marks off philosophy from the special sciences, the second part marks it off from supernatural theology.
We must remember, however, that these three departments of knowledge—scientific, philosophical, and revealed—are not isolated from one another in any man's mind; they overlap in their subject-matter, and though differing in their respective standpoints they permeate one another through and through. The separation of the special sciences from philosophy, though adumbrated in the speculations of ancient times and made more definite in the middle ages, was completed only in modern times through the growth and progress of the special sciences themselves. The line of demarcation between philosophy and supernatural theology must be determined by the proper relations between Reason and Faith: and naturally these relations are a subject of debate between philosophers who believe in the existence of an authentic Divine Revelation and philosophers who do not. It is the duty of the philosopher as such to determine by the light of reason whether a Supreme Being exists and whether a Divine Revelation to man is possible. If he convinces himself of the existence of God he will have little difficulty in inferring the possibility of a Divine Revelation. The fact of a Divine Revelation is a matter not for philosophical but for historical research. Now when a man has convinced himself of the existence of God and the fact of a Divine Revelation—the preambula fidei or prerequisite conditions of Faith, as they are called—he must see that it is eminently reasonable for him [pg 006] to believe in the contents of such Divine Revelation; he must see that the truths revealed by God cannot possibly trammel the freedom of his own reason in its philosophical inquiries into ultimate problems concerning man and the universe; he must see that these truths may possibly act as beacons which will keep him from going astray in his own investigations: knowing that truth cannot contradict truth he knows that if he reaches a conclusion really incompatible with any certainly revealed truth, such conclusion must be erroneous; and so he is obliged to reconsider the reasoning processes that led him to such a conclusion.[6] Thus, the position of the Christian philosopher, aided in this negative way by the truths of an authentic Divine Revelation, has a distinct advantage over that of the philosopher who does not believe in such revelation and who tries to solve all ultimate questions independently of any light such revelation may shed upon them. Yet the latter philosopher as a rule not only regards the “independent” position, which he himself takes up in the name of “freedom of thought” and “freedom of research,” as the superior position, but as the only one consistent with the dignity of human reason; and he commonly accuses the Christian philosopher of allowing reason to be “enslaved” in “the shackles of dogma”. We can see at once the unfairness of such a charge when we remember that the Christian philosopher has convinced himself on grounds of reason alone that God exists and has made a revelation to man. His belief in a Divine Revelation is a reasoned belief, a rationabile obsequium (Rom. XII. 1); and only if it were a blind belief, unjustifiable on grounds of reason, would the accusation referred to be a fair one. The Christian philosopher might retort that it is the unbelieving philosopher himself who really destroys “freedom of thought and research,” by claiming for the latter what is really an abuse of freedom, namely license to believe what reason shows to be erroneous. But this counter-charge would be equally unfair, for the unbelieving philosopher does not claim any such undue license to believe what he knows to be false or to disbelieve what he knows to be true. If he denies the fact or the possibility of a Divine Revelation, and therefore pursues his philosophical investigations without any regard to the contents of such revelation, it is because he has convinced himself on grounds of reason that such revelation is neither a fact nor a possibility. He and the Christian philosopher cannot both be right; one of them must be wrong; but as reasonable men they should agree to differ rather than hurl unjustifiable charges and counter-charges at each other.
All philosophers who believe in the Christian Revelation and allow its authentic teachings to guide and supplement their own rational investigation into ultimate questions, are keenly conscious of the consequent superior depth and fulness and certitude of Christian philosophy as compared with all the other conflicting and fragmentary philosophies that mark the progress of human speculation on the ultimate problems of man and the universe down through the centuries. They feel secure in the possession of a philosophia [pg 007] perennis,[7] and none more secure than those of them who complete and confirm that philosophy by the only full and authentic deposit of Divinely Revealed Truth, which is to be found in the teaching of the Catholic Church.
The history of philosophical investigation yields no one universally received conception of what philosophy is, nor would the definition given above be unreservedly accepted. Windelband, in his History of Philosophy[8] instances the following predominant conceptions of philosophy according to the chronological order in which they prevailed: (a) the systematic investigation of the problems raised by man and the universe (early Grecian philosophy: absence of differentiation of philosophy from the special sciences); (b) the practical art of human conduct, based on rational speculation (later Grecian philosophy: distrust in the value of knowledge, and emphasis on practical guidance of conduct); (c) the helper and handmaid of the Science of Revealed Truth, i.e. supernatural theology, in the solution of ultimate problems (the Christian philosophy of the Fathers of the Church and of the Medieval Schools down to the sixteenth century: universal recognition of the value of the Christian Revelation as an aid to rational investigation); (d) a purely rational investigation of those problems, going beyond the investigations of the special sciences, and either abstracting from, or denying the value of, any light or aid from Revelation (differentiation of the domains of science, philosophy and theology; modern philosophies from the sixteenth to the nineteenth century; excessive individualism and rationalism of these as unnaturally divorced from recognition of, and belief in, Divine Revelation, and unduly isolated from the progressing positive sciences); (e) a critical analysis of the significance and scope and limitations of human knowledge itself (recent philosophies, mainly concerned with theories of knowledge and speculations on the nature of the cognitive process and the reliability of its products).
These various conceptions are interesting and suggestive; much might be said about them, but not to any useful purpose in a brief introductory chapter. Let us rather, adopting the definition already set forth, try next to map out into its leading departments the whole philosophical domain.
III. Divisions of Philosophy: Speculative and Practical [pg 008] Philosophy.—The general problem of classifying all the sciences built up by human thought is a logical problem of no little complexity when one tries to work it out in detail. We refer to this general problem only to mention a widely accepted principle on which it is usually approached, and because the division of philosophy itself is a section of the general problem. The principle in question is that sciences may be distinguished indeed by partial or total diversity of subject-matter, but that such diversity is not essential, that diversity of standpoint is necessary and sufficient to constitute distinct sciences even when these deal with one and the same subject-matter. Now applying this principle to philosophy we see firstly that it has the same subject-matter as all the special sciences taken collectively, but that it is distinct from all of them inasmuch as it studies their data not from the standpoint of the proximate causes, but from the higher standpoint of the ultimate causes of these data. And we see secondly that philosophy, having this one higher standpoint throughout all its departments, is one science; that its divisions are only material divisions; that there is not a plurality of philosophies as there is a plurality of sciences, though there is a plurality of departments in philosophy.[9] Let us now see what these departments are.
If we ask why people seek knowledge at all, in any department, we shall detect two main impelling motives. The first of these is simply the desire to know: trahimur omnes cupiditate sciendi. The natural feeling of wonder, astonishment, “admiratio,” which accompanies our perception of things and events, prompts us to seek their causes, to discover the reasons which will make them intelligible to us and enable us to understand them. But while the possession of knowledge for its own sake is thus a motive of research it is not the only motive. We seek knowledge in order to use it for the guidance of our conduct in life, for the orientation of our activities, for the improvement of our condition; knowing that knowledge is power, we seek it in order to make it minister to our needs. Now in the degree in which it fulfils such ulterior purposes, or is sought for these purposes, [pg 009] knowledge may be described as practical; in the degree in which it serves no ulterior end, or is sought for no ulterior end, other than that of perfecting our minds, it may be described as speculative. Of course this latter purpose is in itself a highly practical purpose; nor indeed is there any knowledge, however speculative, but has, or at least is capable of having, some influence or bearing on the actual tenor and conduct of our lives; and in this sense all knowledge is practical. Still we can distinguish broadly between knowledge which has no direct, immediate bearing on our acts, and knowledge that has.[10] Hence the possibility of distinguishing between two great domains of philosophical knowledge—Theoretical or Speculative Philosophy, and Practical Philosophy. There are, in fact, two great domains into which the data of all human experience may be divided; and for each distinct domain submitted to philosophical investigation there will be a distinct department of philosophy. A first domain is the order realized in the universe independently of man; a second is the order which man himself realizes: things, therefore, and acts. The order of the external universe, the order of nature as it is called, exists independently of us: we merely study it (speculari, θεωρέω), we do not create it. The other or practical order is established by our acts of intelligence and will, and by our bodily action on external things under the direction of those faculties in the arts. Hence we have a speculative or theoretical philosophy and a practical philosophy.[11]
IV. Departments of Practical Philosophy: Logic, Ethics and Esthetics.—In the domain of human activities, to the right regulation of which practical philosophy is directed, we may distinguish two departments of mental activity, namely intellectual and volitional, and besides these the whole department of external, executive or bodily activity. In general the right regulation of acts may be said to consist in directing them to the realization of some ideal; for all cognitive acts this ideal is the true, for all appetitive or volitional acts it is the good, while for all external operations it may be either the beautiful or the useful—the respective objects of the fine arts and the mechanical arts or crafts.
Logic, as a practical science, studies the mental acts and processes involved in discovering and proving truths and systematizing these into sciences, with a view to directing these acts and processes aright in the accomplishment of this complex task. Hence it has for its subject-matter, in a certain sense, all the data of human experience, or whatever can be an object of human thought. But it studies these data not directly or in themselves or for their own sake, but only in so far as our acts of reason, which form its direct object, are brought to bear upon them. In all the other sciences we employ thought to study the various objects of thought as things, events, realities; and hence these may be called “real” sciences, scientiae reales; while in Logic we study thought itself, and even here not speculatively for its own sake or as a reality (as we study it for instance in Psychology), but practically, as a process capable of being directed towards the discovery and proof of truth; and hence in contradistinction to the other sciences as “real,” we call Logic the “rational” science, scientia rationalis. Scholastic philosophers express this distinction by saying that while Speculative Philosophy studies real being (Ens Reale), or the objects of direct thought (objecta primae intentionis mentis), Logic studies the being which is the product of thought (Ens Rationis), or objects of reflex thought (objecta secundae intentionis mentis).[12] The mental processes involved in the attainment of scientific truth are conception, judgment and inference; moreover these processes have to be exercised methodically by the combined application of analysis and synthesis, [pg 011] or induction and deduction, to the various domains of human experience. All these processes, therefore, and the methods of their application, constitute the proper subject-matter of Logic. It has been more or less a matter of debate since the days of Aristotle whether Logic should be regarded as a department of philosophical science proper, or rather as a preparatory discipline, an instrument or organon of reasoning—as the collection of Aristotle's own logical treatises was called,—and so as a vestibule or introduction to philosophy. And there is a similar difference of opinion as to whether or not it is advisable to set down Logic as the first department to be studied in the philosophical curriculum. Such doubts arise from differences of view as to the questions to be investigated in Logic, and the point to which such investigations should be carried therein. It is possible to distinguish between a more elementary treatment of thought-processes with the avowedly practical aim of setting forth canons of inference and method which would help and train the mind to reason and investigate correctly; and a more philosophical treatment of those processes with the speculative aim of determining their ultimate significance and validity as factors of knowledge, as attaining to truth, as productive of science and certitude. It is only the former field of investigation that is usually accorded to Logic nowadays; and thus understood Logic ought to come first in the curriculum as a preparatory training for philosophical studies, accompanied, however, by certain elementary truths from Psychology regarding the nature and functions of the human mind. The other domain of deeper and more speculative investigation was formerly explored in what was regarded as a second portion of logical science, under the title of “Critical” Logic—Logica Critica. In modern times this is regarded as a distinct department of Speculative Philosophy, under the various titles of Epistemology, Criteriology, or the Theory of Knowledge.