With respect to the relation of faith to knowledge: we must remember that the positive dogmas of a fixed definite creed belong to theology, and lie altogether out of the domain of philosophy. For though a truly learned exegesis of Holy Writ most unquestionably demands a truly philosophical spirit, it is not philosophy itself. And this applies also to ecclesiastical tradition, as running parallel to and co-ordinate with written revelation. This enlarged assumption, however, of a twofold source for deducing a knowledge of the truths necessary to be believed, and for their dogmatic interpretation, as touching on a particular province of history, or as some, perhaps, will rather say, a controverted point of church authority, must be left to theology to discuss and decide. It does not fall within the true limits of philosophy, which properly is concerned only with faith in general, and the notion thereof relatively to knowledge. And here comes in the greatest of the distinctions between the philosophy of life (which is founded both on an external and also an internal and higher experience, being itself a science of experience) and the philosophy of absolute reason. The relation between faith and knowledge, as respectively established by them, is thoroughly and essentially different. According to that absolute view of the world and things which rests on and springs from a pure and necessary rational science, faith and knowledge stand in absolute opposition to each other. The only connection into which they can possibly enter is that by which faith is called in to the aid of reason, and in order to supply its deficiencies. When, for instance, the unconditional science can not by itself attain to fullness and perfection of knowledge, or, after all its labors, finds itself standing unsatisfied even within its own domain, then the transition is made forcibly, and, as it were, by a great and sudden leap into the opposite and totally different domain of reason, in order to seek there refuge and protection from itself. And this indeed is the only way still open, if not to a complete reconciliation between the two, yet, at least, to a peaceful compromise of the respective claims of knowledge and of faith. Quite different, however, is the relation between them, as set forth by the philosophy of life, which takes its position in experience and the knowledge which is based thereon. For, in the first place, faith and knowledge are not so rigorously separated, nor so absolutely distinguished in it as they are in the preceding system. And, secondly, as regards the order and succession of the two: here, in the wide field of man’s experience, both inward and outward, in nature and in his own self, it is faith for the most part that furnishes the beginning and foundation of knowledge, which, however, as such is incomplete, and requires further development. We have already remarked, that the positive dogmas of a particular faith, together with the scientific investigations appropriate to them, form a special domain of higher experience. This is a statement which scarcely requires any labored proof. And we need not dwell on it further than to remind you, that even here the faith, so far as it is dogmatically propounded, forms the foundation. In this higher region faith is the first and that which makes the beginning, while the knowing forms the further development. Descending into its particular applications, the latter furnishes an explanation, or, rather, elucidation, of the whole. Still it must all the while adhere faithfully to the fact of a revelation, and maintain its authority over the rational principle which otherwise seeks to depress, and does often actually overbear it. And so is it also with the first awakening of the consciousness. And even in experimental science, the order between faith and knowledge is exactly the same. In actual life, too, every great enterprise begins with and takes its first step in faith. In faith Columbus, compass in hand, and firmly relying on its revelations, traversed, in his frail bark, the wide waters of an unknown ocean. In this faith he discovered a new world, and thereby opened a new era in the history of science and of man. For all his inquiries, all his thirst and search after information, all his thinking, guessing, and supposing, did not as yet amount to a complete knowing—by such means he could not succeed in working out a full conviction, either for himself or for others. It was the given fact, the unquestionable proof of actual experience, that first exalted his bold conception into true and perfect certainty. In a greater or less degree this is the course by which all the great discoveries in science have been made; passing by a slow but still advancing process of thought from faith up to knowledge. And the same character of faith is stamped on every great and decisive act, every important event in the history of individuals or of nations. And if, in contrast with these grander phenomena, an instance be required from the first and almost unnoticeable beginnings of consciousness, I would refer to the first time that, with manifest purpose, the infant seeks and finds for itself its mother’s breast. But perhaps the force of this illustration may be questioned, as being drawn from what might be called a mere gratification of an animal want. I shall therefore take one which borders closely indeed on the former, but which does not appear to be so immediately connected, not to say identical, with instinct. We will take, then, the second moment of consciousness—that at which the child regards its mother for the first time, full, apparently of reflection, and, certainly of attention and meaning, as it were with a wish to say something, if it had the power to talk. And this eye, upturned for the first time, full of love and meaning, what is it but the first look of faith? And though even this opening dawn of consciousness involves a certain distinction and recognition, it is still very far from the certainty of knowledge. And is not the former instance highly appropriate and well fitted to illustrate the relation in which man stands to God? For that paternal heart, which, as the living pulse of omnipotence, beats sensibly in the boundless universe—is it not also, as it were, the full maternal fountain at which the immortal spirit imbibes its first milk, and indeed all its nourishment for eternity? In short, at the vivid point of experience, the first—the still delicate and innocent—beginnings of feeling are very often in close contact with the full maturity of the most enlightened knowledge, expanded and elevated to the height of its Infinite source.

At this point, then, of living experience, faith and knowledge are not so sharply separated from, or so unconditionally opposed to, each other as is commonly thought. The relation of faith to knowledge is that nearly of the beginning to the consummation. Such, too, is the case with experience and revelation, as the data of all scientific knowledge. These two also stand in close dependence on each other. Their mutual relation is something similar to that of the external manifestation to the inward energy—of the visible body to its animating principle, or to that inward spark of light which the body serves as an organ and vehicle, or as an outward garb and veil. In history, and in every science that in any way deserves to be called historical, the spirit or mind has been long and generally acknowledged to be the first and only thing that gives to the whole its true worth. And in the domain of physical science, which of all branches of mere empirical knowledge is the most comprehensive and most extensive, the case is precisely similar. The externally given phenomenon of the fact or natural object that is under consideration, forms only the outward investiture and is to be regarded as the mode of manifestation—the visible form—of the inner life, and law which rules within it. And man’s chief object in investigating the former is, if possible, to pierce its shroud, and to seize and to discover the inward law of life, as all that is most essential, and as the germ of existence, which is wrapped up and hidden in the outward and sensible veil. Many of the special branches of physical inquiry, such as botany and mineralogy, can only be considered as preparatory labors, which are to furnish the materials and apparatus for future science to act upon, and not really as sciences. When all the facts of mineralogy shall have been brought under one great and universal law—when the isolated results of anatomical research and observation can be reduced to one common physiological idea—when chemistry, by its exclusive analysis, and decomposition of matter into its ultimate elements, shall be able to discern, in the different gases and other imponderable agents, the various forms of the invisible principle of things—when a higher range of physical research shall penetrate the grand primal phenomena of the electric shock, of magnetic attraction, and the prismatic decomposition of light, and its artistic imitation for scientific purposes, then only shall we be able to remove the last veil which shrouds the mysteries of nature.

For the whole effort of natural science is indefatigably directed to reaching to that hidden center of life through external existence, of whose inner light and splendor the whole corporeal mass of the sensible world is but the broken and multiplied reflection, and empirical science but the chemical precipitate, the gross material residuum of its pure and spiritual truth. It is to this that all the results of science point and tend; every investigation in the domain of natural history, which in any degree pretends to be philosophical, likewise leads to this conclusion. Assuming, then, the existence of a God as the Creator of the world, what else can nature be than a revelation of God and divine love—a visible manifestation thereof in outward and material matter? And how, if otherwise conceived of, can it ever be understood or comprehended? Supposing also (what at the first we may very well allow) that even from this point of view much remains obscure, enigmatical, and unintelligible to us—still these incomprehensible, or, rather, uncomprehended, matters are merely a few individual instances. The whole, nevertheless, will, on this hypothesis, be found full of deep significancy, and satisfactory, not only to the feelings, but even to the inquiring and questioning intellect. But, according to the opposite view of the universe, though many, or, let us say, very many individual facts in nature may be acutely explained and scientifically understood; still the whole, if it be not looked upon as a revelation from God, but a peculiar self-existent entity, remains forever an enigmatical mass of indissoluble complications. Stripped by this hypothesis of its higher design of leading man onward to the divine, it becomes, for him at least, perfectly unmeaning. But when, on the contrary, the universal system of nature is regarded as the unfolding and visible revelation of the hidden majesty of the Creator, then, together with that other one which is written and contained in the divine law and sacred records, it forms one consistent whole. Holy Writ and nature, according to this view, appear two mutually explanatory and supplemental halves of that book of God which is written on the inside and the out. The inner voice of conscience also has often, and indeed from the very earliest times, been represented as a revelation, though of a different kind; and the moral feeling and its peculiar law have been supposed to be frequently opposed to, or at least wholly independent of, nature and the natural law. But even this internal revelation is also double, like the external one of Holy Writ and of nature. For in its negative prohibitions, in its gentle or terrible, but ever-distinct warnings, as well as in its positive requisitions, it is quite distinct from its other form as a feeling of devotion and of mental prayer, or of an illimitable aspiration after God and divine things. And it is by no means allowable to confound or mix up these two distinct forms. For the one is universal, however variable in its degrees of intensity; whereas the other manifesto itself rather by way of exception as an individual vocation, or, if the term be preferred, as a peculiar genius for piety, and a special sensibility for holy thoughts and feelings.

Now this fourfold divine revelation, embracing the two external branches of Scripture and of nature, and the two inner ones of conscience and devotion, has its seat in the four faculties of the lower order which have so repeatedly been brought before our consideration. For the memory is the organ of its written and oral transmission and perpetuation—nay, of writing and language generally, according to the intimate connection which subsists between them. And in the next place, the external senses, with which we may also associate an immediate intuition into the depths and mysteries of nature, are the organs for perceiving and understanding the sensible phenomena. Lastly, there is conscience, and, on the other side, a longing after God and divine things, as the highest and most enhanced degree of human pursuit—of the profoundest aspiration of man’s soul, and the purest desire of his spirit. For it is even here, in these subordinate faculties, where the deep decline and gross degeneracy of the human mind in its present state most strikingly displays itself, that a susceptibility for improvement is first excited. Here springs the earliest impulse to return to the higher state from which we have fallen. Here the divine seed of resuscitation soonest expands itself, revivifying and restoring to its pristine worth and dignity the morbid and lifeless consciousness. The internal revelation, however, of devotion and prayer must be regarded as clearly distinct from, and as lying altogether out of, the domain of philosophy, even as the learned exposition of Scripture, and a scientific study thereof, forms a peculiar branch of intellectual pursuit. But though philosophy must not be mixed up with it, yet on the other hand it must not lapse into, or inseparably identify itself with, a pure mysticism of devotional feelings, or, if the term be preferred, a theory of prayer, and a mere contemplative meditation on the Deity and divine things. And the reason is obvious: devotion, with its mystical feelings, must necessarily and absolutely attach itself to the positive data of a fixed dogmatic faith. For in such alone can it find, not only a definite form and a maturely-developed external shape, but also an inner assurance for itself as well as a safeguard against the possible errors of fanaticism.

And here, however, it must not be forgotten that the intrinsic essence of divine longing, as well as of all other holy feelings, can never be or seem alien and repugnant to the philosophy of life, which indeed takes its rise out of this very center of a high and holy love. On the contrary, it must always be intimately associated with and amicably disposed toward it. The philosophy of life, therefore, even while it carefully guards against falling into a mere exposition and commentary of Scripture, may freely borrow from the old Scriptural language its awful spiritual phrases and its vividly forcible expressions. It would, in fact, be an overstrained pedantry, and an excessive affectation of scientific purism, were it to wish to avoid it. Still it is necessary to draw a precise line of demarkation between religion and philosophy, and carefully to observe their limits. And in the same manner, philosophy will abstain from an undue encroachment on the province of natural history, or on the domain of ethics where the internal revelation of conscience furnishes the basis of all moral legislation. At least it will keep from so doing as long as it is anxious to preserve its true dignity as a philosophy of life, and of thought and science in general, and fears to degrade itself by becoming nothing more than a special branch and application, either as mere morals or natural philosophy. This, however, does not preclude from it the liberty of occasionally entering even deeply into them, or of taking a general survey of their results, or borrowing largely from their facts, as pregnant instances, remarkable phenomena and similes, in order to make this remote region illustrate its own sphere, though properly they do not belong to it. Philosophy has enough to do with what really forms the subject-matter and contents of its own province, without seeking to enlarge it by any extraneous addition.

Now, to these four forms or sources of a higher revelation, both internal and external, a fifth remains to be added. It constitutes, as it were, their common bond of union—the center at which, converging and coming into contact, they exercise a mutual influence, and, adjusting and accommodating themselves to one another, combine in living union and perfect harmony. This we would designate by the general name of a revelation of eternal love. But a revelation of eternal love in man, and not merely such a one as we might, with good reason, pronounce nature and the whole creation to be. And even when we say in man, we do not merely mean thereby such as is revealed in his instinctive emotions of devotion and religion, but that, rather, which speaks out in man’s most universal feeling, and in his profoundest and intensest consciousness. But if love itself is nothing but the pure idea, the inmost spirit and essential energy of all true life, and especially of that which is highest and most exalted, then must this revelation of love be pre-eminently the subject-matter of the philosophy of life. For it is even the rich and intrinsic center of the other four sacred sources of divine revelation, and out of it all higher life, thought, faith, and science, flows into the soul of every man that has any susceptibility for such exalted excellence. This remark, moreover, implicitly determines the relation which both faith and enthusiasm (according to the Platonic notion of it) hold in general to science, and also to revelation and love, though, indeed, with respect to the latter, it is only inchoately and in outline that it is so fixed.

But, in order fully to work out and complete the idea of science, according to all those external relations which we have already laid down, it will be necessary to examine the several elements of this idea in their internal coherence, and also, by means of contrast with a complete evolution of the system of inborn error, to set them in the fullest and clearest light.

We have already declared and enumerated the several elements and degrees, or species and constituents which, together, make up scientific knowledge. First of all, there is the understanding and explaining, the discerning and distinguishing. In the second place comes the living cogitation or complete comprehension of the actual, which forms the true center of scientific knowledge, if not its very self; and, lastly, that which is closely connected therewith, the immediate perception and recognition of truth, and an inward feeling of certainty. All these, however, are more or less falsified and led astray by the principal of those scientific errors which are innate in man’s mind—which sometimes secretly undermine, and, at last, totally subvert and destroy them. First of all, the living thought is often converted into a dead cogitation, being carried away from its natural direction toward the actual, and misled to an unsubstantial pursuit of empty abstractions. The total confusion of ideas which this leads to is fatal to all distinctness and precision of understanding, and renders it impossible to have a clear discernment and correct judgment of things. And then, in this bottomless abyss, the firm foundation of actual truth and inward certainty sinks and is swallowed up.

Every one, indeed, of the four fundamental faculties of the human mind contains, in itself, a faulty disposition and pernicious germ of a special and precise form of scientific error, which establishes and fully develops itself in its appropriate domain, and which, when circumstances are favorable, is matured and shaped into a system of falsehood. It is chiefly in the visible consequences of its further development, and, also, by the intrinsic inconsistencies in which it is involved by the unfounded assumption from which it sets out at the very first, that each of these abortions of unsubstantial and empty cogitation is most easily detected. And, in fact, in the history of the human mind and philosophy, and even of science generally, the essential characters of these leading phases of scientific aberration are only too distinctly legible to him who contemplates that great intellectual picture with an eye unblinded by prejudice.

The error most peculiar to the reason, and which, in its domain, springs up almost indigenously, is one that has already been frequently mentioned—viz., the phantom, of the unconditional, or the delusion of absolute necessity. Now, all the data on which man’s knowledge must be based have a triple source; they are presented to him from within, from above, and from without. But the reason, which is the faculty of the logical connection of ideas, and of the logical necessity which rules in that connection, often quits this safe and solid ground of reality, as presented to it in triple experience, whether of revelation and history, or of natural science, and resting entirely on itself, tries to build exclusively on its own foundation. Whenever, therefore, it attempts this impossibility, it invariably copies the mathematical method of demonstration. And so there immediately springs up the false semblance of a necessary knowledge. As the faculty of logical thinking, the reason is at the same time a power of endless progressive development. To invent, however, to create and to produce, is absolutely beyond its capacity; and it forfeits its own rights, whenever, abandoning the pursuits most appropriate, and assigned to it by nature, it usurps the prerogatives of an inventive and productive faculty, and thereby gives birth to the abortions of false metaphysical systems.