The intellectual processes of a rational being must proceed according to some law. They cannot succeed each other at hap-hazard. The notion of rationality is conditioned upon this regular procedure; if this be wanting, the essential character of rational action is wanting. But to say that rational processes are determined by law, and conditioned upon a regular procedure, is simply to assert that the steps in ratiocination are so related to each other that the relation of each to every other may be determined by the application of the law—the difference between any two steps being analogous to the difference between any other two. The astronomer determines the orbit of a planet from three observations, because he thereby determines the law of variation between these points; from which he assumes that this law will be constant, presenting a series of terms each differentiated according the series of differences already determined.

Applying the same principle to mental phenomena, we may determine the law of intellectual action. Thoughts are discriminated by the presence or absence of certain attributes. At one extreme we find the summum genus, comprising the fewest possible attributes distinguishing an idea; at the other extreme we find the individual, comprising any number of attributes. Between these two extremes we find a regular series of intermediate terms. The movement of an idea from the general to the individual is like the motion of a planet through one-half of its orbit; while the return movement from the individual to the general, corresponds to the motion of the planet over the remaining half of its orbit. The same law governs both movements and unites the two halves of the orbit into a single whole; and a series of observations taken at equal distances, will, by the uniformity of differences presented, reveal the operation of the same law in this dual manifestation. Upon examining the processes of deduction and induction, we find in each the same series of terms, differing only in the fact that they are in inverse order, and this correspondence reveals the operation of one and the same law. An inductive series is only a deductive series read backward. Any two terms in a series whether inductive or deductive, differ only in the degree of generality, and differ similarly from a third term, so that two being known the third can be therefrom determined. In a deductive series the terms differ by a constant increase in the number of individualizing attributes—a concept being expanded into a deductive series by such regular additions. Having two terms we can proceed to the third—that is, from two propositions expressing this relation, we can proceed to a conclusion. In an inductive series the terms differ by a constant diminution in the number of individualizing attributes—an individual term being expanded into an inductive series, by successively dropping the attributes which compose the individual term, until we reach the required degree of generalization.

Thought must proceed in one of these two directions. The object-matter of thought being composed wholly of attributes can differ only in the presence or absence of certain attributes. A combination, then, of these two movements must complete the intellectual orbit. The direction of the movement of the mind will be determined by the end proposed. When we possess the knowledge of phenomena and wish to discover law—that is, when we seek information—we proceed by induction, from the individual to the general. When possessed of knowledge, we wish to discover its applications, when knowing the law, we wish to determine the phenomena necessarily resulting therefrom, we proceed by deduction—from the general to the individual. Complete knowledge, then, consists in the highest possible generalization, and the expansion of this term into a series, ending only with the last possible individualization. The aim of physical science is to determine that half of the intellectual orbit which lies between the individual and the general—the aim of metaphysical science is to trace the other half which lies between the general and the individual. When we seek to know what is, we proceed by induction—the method of the phenomenal. When, knowing what is, we proceed to determine what hence must be, we proceed by deduction—the method of the Necessary. Thus Science, at first seeking principles, proceeds by induction to establish them; but after these fundamental principles have been established, it proceeds deductively to determine what must result from them, without waiting to discover these truths by observation.

Knowledge is thus complete just in proportion to the extension of its scope through generalization. The higher the generalization, the more inclusive will it be, and the summum genus, or the final generalization, will be the highest attainable reach of knowledge. When man can make no further generalization, his knowledge will be, in so far, absolute and complete, and all that remains possible to him will be the practical application of what he already knows. Perfect knowledge is nothing but perfect generalization. The Supreme Intelligence being hypothetically possessed of all knowledge, that is, having discriminated the absolute summum genus, can proceed no further in this direction; his intellectual activity must be exerted in a descending series, or from the general towards the individual, and this process must be, as we have seen above, by a determinate series of steps, fixed by the operation of a definite law, which law proceeds by the successive addition of attributes to the general.

Complete knowledge, being complete generalization, the lines of all science will necessarily converge, as they approach this generalization, until all sciences coalesce in one science, and all truth is reduced to a single expression in the utterance of the final conception. In accordance with the laws of thinking, this general term is reached by successive omissions of particularizing attributes, until at last we reach Being—the absolute summum genus, wholly free from individual attributes, and thereby embracing everything possible to thought, whether material or immaterial. But this summum genus must be predicable of this whole. Matter and mind may thus be reduced to a single category, and the physical and the intellectual finally coalesce in this last generalization. Materialism and idealism thus differ merely in the degree of generalization reached—or rather they both agree in avoiding the final generalization which identifies both matter and mind. Materialism must always deal with the individual, for matter can appear under no other form. Idealism must always rest upon the general, for thought, to be thought, must state a generalization. Each, however, finds its explanation in the other, and both are harmonized by the application of the law of intellectual action above given. Matter and Mind are complementary, not incompatible. They differ with each other, but they agree in being similarly related to a third term. Matter is objective; it is thought taking form, becoming individual, manifesting itself in space. Mind is subjective. The one appeals to the senses; the other is known only to the consciousness.

Science reaches its full development only when it includes both physical and intellectual phenomena within its scope. Every step which it takes carries it further from the purely physical, and brings it nearer the purely intellectual—that is the development of physical science is from the individual towards the general, and it reaches its end, its completion, only when the last distinction, that of subjective and objective, has disappeared in the last possible generalization. When the objective has been identified with the subjective, the distinction between Mind and Matter has been obliterated, and we have reached the Supreme Intelligence—the "I Am" of Scripture—simple Being.

Matter is the formal expression of thought, or the necessary condition of such expression, and in this condition is found the link that connects the subjective and objective manifestations of being. Subjectivity is ideality, as objectivity is materiality. The consciousness can take cognizance only of what is within itself, and therefore without every other. Consciousness is therefore wholly personal. To communicate an idea it must be placed within the consciousness of another. To reach this result it must cease to be personal, must pass out of the subjective consciousness into objective form, so as to be placed in the same relation to the speaker and the hearer. Thought, out of the consciousness of the thinker, is objective to him, and to render thought objective is to give it material form. Thought to be communicated, must pass out of the consciousness of the thinker into a material representation. The assumption of material form individualizes the idea. The artist's mind may be filled with splendid conceptions, but no one but he can look within his consciousness and see them. Before others can have any knowledge of his thoughts, he must give them form, or embody them in statues or paintings. The soul of the musician may be thrilled by the harmonies that his imagination creates, but no other soul can join him in this ecstasy until he has given form to his conceptions. So the thinker must embody his thoughts in language before he can communicate them to another. Matter, then, is the vehicle by which thought is communicated, and, so far as we are concerned, the necessary condition of such communication, so that the conception of thought apart from the thinker involves the intervention of material forms, and it is by the interpretation of these symbolical forms that we discover the idea.

Now, let us suppose a Supreme Intelligence. The intellectual processes of such a Being, to be conceived as rational by us, must be identical with ours, or at least analogous to ours. The possession of infinite attributes may in fact free him from the control of any law, but it is impossible for us to conceive an intelligence acting otherwise than in accordance with law. So that if the Supreme Intelligence is to communicate with man, it must be in obedience to the laws which control our mental activities. The Divine thought must, then, like human conceptions, be communicated by means of physical symbols.

The Supreme Intelligence, being the final generalization, must possess all knowledge, and the only intelligent action possible to him from our point of view, is from this absolute generalization towards the concrete and individual. The absolute general is purely subjective, which, to become cognizable, must be rendered objective. This can be secured to us only through the intervention of material forms. From this point of view, matter is only the symbol of thought—thought apart from the thinker. The first result of the divine activity in self-manifestation would be the analysis of being into subjective and objective—that is the discrimination of mind and matter, which terms are severally the final generalizations of the two fundamental divisions of science. Matter, then, mere formless, chaotic matter, would be the first result of creative activity. Following the development of this idea in its continually increasing individuality, as new attributes are severally added, matter assumes determinate form and becomes related in systems, as the various so-called elementary substances are discriminated, until finally all truth, capable of being revealed by inorganic matter, is presented to us.

Add the idea of organism and we have the two great divisions of phenomena—material and vital. The higher the generalization, the fewer will be the attributes composing the concept, and thus the simpler will be the form symbolizing its expression. As in the case of matter, the first result of the divine activity was more matter, undiscriminated by any further attribute; so here, we have, as the first organic creation, a concrete expression of the highest possible generalization comprising the fewest possible attributes—that is, forms of life involving the fewest individual characteristics. To matter add the simplest organic attribute—that is, the one lying nearest the genus—and we have mere organized matter, the simple cell, the foundation of all life, no matter how great its future complexity, equally the origin of animal and vegetable growth, which are as yet entirely undiscriminated. This would be the first appearance of life.[1] Differentiating again by the addition of a new attribute, and organic being is subdivided into the two species, vegetable and animal. Beginning with these typical forms, adding single attributes in a continuous series, we at last reach the highest types of animals and plants. Finally, add rationality to the animal, and we reach man, the highest and therefore the most complex type of life, and who, so far as we are concerned, must be the end of creation. We cannot conceive of any higher creation, because we cannot add an attribute to those we already possess, any more than we can conceive of an additional sense by which to cognize such new attribute.

This process has been determined from the very outset by those intellectual laws which we cannot disobey, and which we cannot conceive disobeyed by an intelligent creator. If the law of intellectual action require this process from the simple to the complex, the concrete representation of the steps of this process must indicate the operation of this law, and must also proceed from the simple and rudimentary to the complex and highly developed. An intelligent Creator in revealing his thought must follow the method which our minds must follow in interpreting this revelation. When we know and seek to communicate our knowledge, we proceed from the general to the specific.[2] The Creator assumed to be infinite in knowledge would therefore follow this process instead of the method peculiar to investigation. The law of intellectual action determines this method, and the conditions of intellectual communication determine the representation of this method in the material expression of the ideas communicated. Considering the operation of this law under these conditions, we find that the thought communicating only, as nearly as may be, the generic idea, will be distinguished from it by the addition of but a single attribute as the generic by itself is incapable of being represented in concrete form, the expression of this thought in form will present us matter distinguished from matter in general by but a single attribute. The least possible individualizing attribute added to the highest possible generalization gives us the simplest expression of an idea, and the form or the organism symbolizing this thought will be the simplest form and the simplest organism possible. For instance: in organic life the highest generalization barely individualized will give us the simple cell; and no matter what degree of complexity we subsequently reach by the addition of an almost infinite number of attributes, we nevertheless begin in every case with the same starting point.

Each higher type is reached by adding to a lower. The higher thus embraces all that can be found in the lower, and something besides. This method is invariable, and can never be departed from. The genus must always be predicable of every individual component of every species contained under it. Translating this law into the forms of material expression, and it requires each higher species to physically include all lower species, and to differ from them only by addition. Man, the highest type, must thus include all the attributes of the cell as physically expressed, and without them he would not be man. The differences between no two terms in a series can be total. If the successive steps in a train of thought must be related, so that no two notions will be wholly distinct from each other, these notions will constitute a series, each term of which will, in a measure, determine the next, so soon as the law of the series is discovered; and if this train of thought be objectively presented, it will afford a corresponding series of physical terms, each one of which will in like manner determine the next. But thought is impossible unless by a train of ideas so related. Its physical expression will therefore be equally impossible except by a series of physical terms similarly related, each one of which in some manner determines the next. There must then be a perfect continuity in the line that reaches from the simplest form of matter through all grades of organic life up to man, the highest expression of the divine idea. There can be no break in the chain of thought, because the law of the logical process forbids it: there can be no break in the series of material symbols for the conditions of concrete expression equally forbid it. A symbol is nothing except as it represents that which is to be symbolized. So the symbols form a physical series, because the thoughts symbolized form a logical series.

If the creator has fully revealed his thought, it must be by a series of physical terms arranged in such a manner as to indicate the logical series of ideas symbolized. Every form of matter is a symbol of thought, and challenges interpretation. Every change in form corresponds to an antecedent change in idea, and must be intended to reveal it. As thought, then, begins its evolution with the general and proceeds to the individual by a series of terms each of which is similarly related to both extremes, we must find the material enunciation of this process assuming the form of a series of terms, beginning with mere nebulous matter, grading into organic life, and organic life presenting us with a similar series beginning with the mere cell and ending with man. So rigid and invariable must this serial arrangement be that if a term in either series be wanting, we are authorized to hypothetically interpolate it.

"Nature never makes a leap," says the scientific investigator, as he studies the material symbols of thought. "Thought never makes a leap," says the metaphysician, as he studies the necessary laws of rational action: and both have uttered the same truth. We prove a proposition by determining the steps by which it was educed from a more generic statement. Science must proceed in the same manner, for science only discovers the track of mind—it does not make the track, it only follows it. If then we find the chain of evolution broken at any point, science must either stop there, or assume the wanting term in the series. We have the right to interpolate these missing terms, for we must assume that the thoughts of God communicated to us in material forms constitute a continuous revelation, beginning with Himself, the final generalization, and ending with man the highest individualization. These limits are fixed—the one by the nature of God, and the other by the nature of man. Between these two extremes we must find a series of intermediate terms. Any other conception of their relation than that of a determinate series is impossible and irrational; and a series, so far as it means anything, means evolution of some sort. Finding the relation between these terms—distinguishing the same which reproduces itself, and the different which introduces a new term—that is, determining the law of apparent evolution—is the problem presented to science.

The astronomer found Bode's law to all appearance violated by the omission of a planet between Mars and Jupiter. He could see no reason for the law, but if the planets had been placed by an intelligent Creator, some order of arrangement must be discoverable according to which their position was determined. The Creator being intelligent, it is impossible to conceive them placed fortuitously. There must then be a link between Mars and Jupiter, because the law once established cannot be broken. The same law may be observed in the arrangement of leaves around the axis of a plant. If intelligence arranged them they must be arranged in some order, for intelligence never performs the least act without a purpose. Each leaf or pair of leaves is not a mere duplication of the previous leaf or pair of leaves. The relation which subsists between any two sets in the series expresses the idea of the Creator, and this must be constant. Completing the series as indicated by different plants, we may assume that if any term is apparently wanting, it is only because it has not been discovered. In neither of these cases would it be asserted that any physical evolution had taken place—the terms form a series of which each term is equally determined by the operation of a fixed law; and yet it is an operation precisely analogous to that which in the case of animals presents every appearance of a real evolution. Take, for instance, a series of animals, presenting at one period of time the simplest and most rudimentary forms, and at another the most complex and highly organized; we cannot do otherwise than conceive these two extremes as related by intermediate terms, through the operation of some law which holds good throughout the series. The relation subsisting between any two, must be the same as that subsisting between any other two similarly situated, or a departure from that relation which is itself governed by a definite law discoverable from a comparison of two sets of terms. The application of this law is so universal and so rigid that we need not hesitate to interpolate a missing term, and confidently assert that it either does exist or has existed. To deny this principle is to deny the necessity of continuity in reasoning. This continuity of thought is represented in matter by the persistence of generic forms under specific differences. But just as the specific is the generic with certain additions, so the individual is this same generic with still further additions; and these additions, whether considered solely in space, as given in the symbols of physical science, or in time as in the conceptions of intellectual science, must be determined by the same unvarying law. The persistence of the same form furnishes us the means of identifying this relation, while the differences reveal to us the successive steps by which the generic was differentiated into the individual.

If the creative thought has been expressed by the forms of matter, the laws of thought must be thus expressed in the relative forms of matter. Anything less than this, while it might interpret isolated ideas, would not communicate the method of the creative process, and science is nothing but the discovery of this method. If the terms of the logical process must be arranged in a series, the physical symbols rendering this logical process cognizable, must be arranged in a similar series, for science becomes impossible when the logical process becomes undiscoverable.

The differences between the terms in this series must be cognizable. Two terms which are indistinguishable are practically identical; and two terms which are not identical vary by a difference which is cognizable by itself apart from either term. The steps in the logical evolution of the final term. Being must be separable to be cognizable, and the material forms interpreting these steps to the senses must also be distinguishable. A species differs from the genus by the addition of at least one attribute. Now, if the species is distinguishable from the genus, the attribute which differentiates it, must be separately cognizable—so also the individual differs from the species by the addition of attributes, which must in like manner be separately cognizable, or the species will never be conceived independently of the individuals. A thought cannot proceed by insensible steps, nor can its material expression vary otherwise than by determinate and distinguishable differences. The distinction of species is thus a logical necessity. The addition of distinct attributes to the genus gives origin to distinct species; variation in attributes not affecting their substantial identity gives rise to varieties. One species, then, cannot become another, except by the assumption of a new specific attribute, so that one species passes into another precisely as the genus passes into the species, and that is just as, and not otherwise, than one thought passes into another.

The fundamental law of the logical process is that we pass from the generic towards the individual; from the simple to the complex. Induction can proceed only by assuming a genus at the outset—that is, by assuming certain attributes in the individual to be generic. Translate this law into material forms, and we have each higher—that is more complex—species evolved from the lower by the addition of some new characteristic. This new attribute cannot be added by the functional activity of the lower organism; that can only reproduce itself. A thought does not change merely through repeated expression. We pass to the conclusion of a syllogism, not from each term, but from a comparison of the premises—and this requires an intellectual operation entirely distinct from a mere apprehension of the terms. It is one thing to comprehend the premises; it is quite another to deduce a conclusion from them. It may necessarily follow, but it requires a separate act of the mind to reach it. Premises will not of themselves reach a conclusion.

Reading this same truth in the forms of matter, we may say that species will not pass into higher species without the intervention of a force distinct from either. The impulse which adds a new attribute must be intellectually separable from all those pre-existing, and its material representation must be physically distinct from pre-existing forms. This complete separability precludes the possibility of mere physical genesis. The added attribute is presented by a new form of matter, revealing the presence of a new thought—a new effect, requiring the agency of a new cause. In accordance with the usual economy of nature, who never duplicates her forces, change will be made only so far as may be necessary to communicate the additional idea. Organisms representing previous thoughts will be added to, in order to express the expansion of the thought, instead of a creation de novo in each instance. Thus an identical cellular structure will be found in all organic beings, from the lowest to the highest, each higher type carrying forward the idea and its physical expression found in the lower. The differences between no two terms in the series can be total, nor can any two terms be identical, as each higher species will embrace all the attributes of the lower, differing only by the addition of others. This is simply the physical expression of the logical truth that whatever can be predicated of the genus can be predicated of every individual contained under it. As the individual is only the expansion of the genus, so higher physical types must also be similar expansions of lower.

Here, then, is evolution, or development: primarily an evolution of the generic into the individual, the continued differentiation of a generic idea through successive individualizations, each adding to the previous group of attributes, thus rendering the idea increasingly complex; and, secondly, an apparent physical evolution or development, interpreting this logical process by a series of physical forms so related as to reveal the relation existing between the thoughts thus interpreted. In the physical representation of the ideas so related, there must be an apparent physical evolution—that is, the process of evolution logically must, like the ideas thus evolved, have a physical expression, and the successive steps in this logical evolution must be revealed by material forms bearing an analogous relation, and thereby expressing the logical process. Matter is nothing, so far as we are now concerned, but the condition necessary to the objective expression of thought. Every phase of matter is simply an objective formulation of a corresponding phase of thought. Every addition to form implies an antecedent increase of thought, as there can be no formal expression until there is something to be expressed. There can, then, be no such thing as mere material evolution, for whatever is material is only symbolical.

Matter being thus wholly inert, the origin of the impulse towards greater complexity must be sought for outside of that which undergoes the change. The movement by which one species becomes a higher is not an elaboration, an extension or a differentiation of existing attributes, but involves the positive addition of a new attribute, different and distinct from any or all previously existing. One species cannot pass into another by an innate impulse, for a species is an entity composed of a determinate number of attributes, and all attributes potentially present must be considered as actually present. We cannot say that the child is a different species from the man, and that one passes into the other by a process of evolution, because all the essential attributes of the man are potentially present in the child. If the polyp, by the action of innate forces, operating through a series of ages, however extended, can, without any impulse from without, develop itself into a man, then the polyp is as much a man as a boy is, differing only in the time required for development: and the data for the final deduction of the highest types of creation must be furnished in the most elementary forms of life.

The force manifesting itself in organic life is readily distinguishable from the organism by which it is manifested. Life and organization are not synonyms; one is the condition of the other, but a condition is not a cause. We can consider force apart from organism, and this possible separation in thought proves that the same form may not represent both, but that life can absolutely exist apart from organs which serve to give it a physical manifestation.[3] Physical life being conditioned upon organization, whenever the organism varies, the vital force thus manifested must also vary, such variation being necessarily antecedent to its manifestation. The organism varies, because it must, in order to express the added thought. Change in organism, therefore, is not induced by simple organic action, because the organs and the force acting through them can be distinguished. Assuming that matter is the objective or formal representation of thought, there can be no change in the material expression without a corresponding change in the antecedent conception. There can, then, be physical evolution, only as there is antecedent logical evolution, and then only because of this logical evolution and not because of the operation of an innate organic force. Force, whatever may be its genesis, is only the exertion of power, not the increase of it. Exertion limits the view to the force immediately in operation. We may replace one manifestation by another, but the quantity is neither increased nor diminished by this change. Change in form implies the operation of force: and apart from such manifestation in matter, it escapes the tests of science, and passes into the purely metaphysical notion of cause. And unless the operation of force be constant, or, if different forces are blended, variable according to some determinate law, the action of which is constant and discoverable, so that the different units of force are separately measurable, the force thus irregular in its action can never be placed in any scientific category. Evolution, then, cannot proceed from any innate organic impulse, unless the force that tends to exact reproduction, and the force that induces a change be equally and separately cognizable. Change must proceed according to some law which accounts for the change, and distinguishes between the normal exertion of power and that exertion which causes a deviation. Science, to be science, must explain apparent exceptions as fully as the regular operation of forces, and that which causes the irregularity must be as distinctly cognizably by itself as the force which acts regularly. Anything less than this is not science. The discovery of Neptune was the result of the application of this principle; it was a successful attempt to discriminate the force which caused variation from the force which operated regularly.

Each species represents the operation of certain vital forces, and one cannot physically pass into another except by the increase of this force, or at least by a change in the manner of its manifestation; and this increase in amount or this change in direction must separately be accounted for. Nor does it matter, for the purposes of this discussion, as to the genesis of this added increment, further than to show that its origin must be exterior to the organism by which its presence is manifested; for vital energy acting through an organism is a unit, and cannot, even in thought, be separated into distinguishable portions. Change in the direction of vital energy indicates that the original impulse has been modified in its action by encountering another force, for nothing but force can change the direction of force. It does not fall within the range of this paper to determine the nature of this exterior force which is thus distinguishable from that acting through the vital organization, and therefore capable of separate objective representation. Metaphysically we may say that force is resolvable into will, but will being purely personal is incapable of material representation, and thus cannot enter into the determinations of physical science, which does not seek to discover the origin of force, but deals solely with its presence.

As the logician must assume his premises, and, as a logician, cannot question their truth, so the physicist must assume a force in operation, and, as a physicist, cannot examine its genesis. The physical or the metaphysical method of inquiry is valid only so long as restricted to physical or metaphysical processes: a mixture of the two methods will give results satisfactory neither to science nor to philosophy. As logic furnishes no criterion by which to test the absolute truth of propositions, but deals wholly with conclusions drawn from given premises, so science furnishes no data by which to determine the absolute genesis of force, but restricts its enquiries to the phenomena resulting from a force given. For the student of physical science cause and effect is only the transference of a given and determined force from one material form to another. If this idea is to be traced further, it must be studied outside the limits of physics. This study belongs to metaphysics.

Now, if physical science does not deal with the origin of the initial force, but assumes at the outset its presence, no more does it fall within its province to examine into the origin of the increments which give to physical forms that variety which renders science possible. Science deals with results, not antecedents; and after having determined results, it is not authorized to affirm that one species has produced another by evolution, or has produced it at all. If there are agreements between different organisms by which they are brought into relation, there are also differences by which they are discriminated, and these differences imply increments of force; and to assert that one organism has evolved another is to determine not merely the presence of this new increment, but also to determine its origin. Scientific investigation deals with phenomena which give evidence to the senses of a transference of force from one form or from one manifestation to another. Transference is not increase—an effect can be no more than the evolution of what was potentially present in the cause; it cannot add to it. The origin of the force must be investigated according to intellectual laws.

It has been argued that a Supreme Intelligence in manifesting his thought will, according to the necessary laws of rational activity, pass from the universal and general to the particular and individual, or from concepts involving few attributes to those involving these and others; and that these steps in the rational process must be represented in a corresponding physical series; and that the communication of thought is conditioned upon this physical representation. If the logical series comprises one thousand terms, each related to the preceding according to logical law the physical series must comprise one thousand terms, each physically related in such a manner as to reveal this law. As the highest generalization comprises the fewest attributes, the concrete expression of this idea will present the simplest possible physical form and the least complexity of organization, and thus will present the lowest types of life; and as the individual comprises the greatest number of attributes, its concrete expression will present the greatest complexity, and consequently the highest type of life. We have seen that the logical process begins with the general and ends with the individual; its material expression must therefore begin with the lowest orders and end with the highest. But the individual cannot be immediately derived from the general without the intervention of intermediate generalizations. No more in the concrete expression of this deduction can we pass from the lowest types to the highest without the intervention of an intermediate series. These intermediate terms are not capable of independent interpretation; they find their full explanation only in the extremes of the series—God and Man.

If, then, in the intellectual process from the abstract and universal towards the concrete and individual, we find a constant evolution of idea, each advance being an addition to the previous conception, each new term in the series embracing all the attributes of the preceding, and differing only by addition; and if thought is possible only on this condition; it necessarily follows that the material representation of this thought must present physical forms similarly related, so that, leaving out of view the intellectual genesis of this relation, the observer might conclude that these forms compose a series evolved from a primordial cell in accordance with an organic law. But such we find to be the universal law of intellectual procedure: this apparent development or evolution must, therefore, be the condition of the communication of such intellectual process, and the physical terms are brought into this relation by the fact that they symbolize the logical process. If the material symbols of thought were unrelated physically, the thoughts thus expressed would also be unrelated and independent. But such a supposition readers Science impossible, for its one aim is to find the same in the different. If there be no same, there can be no science: if there be no different, there can be no science. Thought proceeds by adding the different to the same in an endless series, and this addition of the different to the same expressed in concrete forms is what is called evolution. If no evolution were apparent in Nature, there could be no Science; for those steps which to the naturalist indicate evolution, being only the physical expression—the formulation—of the logical process, afford the means by which the student reaches the highest generalization. If these steps be wanting, he cannot proceed.

Admitting then to its fullest extent the fact that, judged from a purely physical point of view, all organic forms seem to have been derived each from its immediate predecessor, by a mere functional impulse; and admitting that science is possible upon no other condition; we claim that these material forms are brought into such relation by intellectual evolution, and not by physical genesis; they represent an evolution of Thought and not an evolution of Matter. We know from consciousness that this process of evolution is the method of our thinking. We know also that the divine thought can be rendered intelligible to us upon no other hypothesis than that which supposes it to be governed by the laws which control human thought. Translating the physical symbols which we see about us, and which present this appearance of evolution, we infer that this is the method according to which the divine mind proceeded. Science will not materially err in its physical results, if it adopt the hypothesis of physical evolution, but it must confine its attention to physics; it is only as we attempt higher generalizations that the insufficiency of the hypothesis becomes manifest in its failure to satisfy the conditions of the problem as presented to philosophy.

[1] This, of course, does not absolutely determine the order of organic creation; as in the case of the syllogism the conclusion or either premise may be the proposition first enunciated, the order of expression being determined by circumstances.