We find the scientific objections to the selection theory collected in detail in the before-mentioned works of Wigand, Blanchard, His, von Baer, and especially in Mivart's "Genesis of Species," (London, MacMillan, 1871); and it is a praiseworthy testimony of Darwin's love of truth, that lately he himself, the originator of the selection theory, willingly admits these weak points in his theory,[7] while Hackel and many of his followers {107} in Germany still stoutly reject every doubt of the autocracy of the selection principle.

In summing up all we have said thus far about the theories of descent, of evolution, and of selection, we still find all three solutions of the scientific problems to be hypotheses, but hypotheses of very different value. The idea of descent has the most scientific ground; it will, as a permanent presupposition, govern all scientific investigations as to the origin of species, even if it does not exclude the idea of an often-repeated primitive generation of organisms--especially of those that stand still lower in development. More uncertain and less comprehensive is the position of the evolution theory; in all likelihood, the idea of an origin through development will have to share the sovereignty with the idea of origin by leaps through metamorphosis of germs. Still more unfavorable is the state of the selection theory. It possesses the merit of having started the whole question as to the origin of species; it may explain subordinary developments; natural selection may have cooperated as a regulator in the whole progress and the whole preservation of organic life.

Ed. von Hartmann, in his essay, "Truth and Error of Darwinism," (Berlin, Duncker, 1875), on page 111, compares its functions with those of the bolt and coupling in a machine; but that the driving principle which called new species into existence lay or originated _in_ the organisms, and did not approach them from without, seems to be confirmed more and more decidedly with every new step of exact investigation as well as of reflection.

* * * * * {108}

BOOK II.

THE PHILOSOPHIC SUPPLEMENTS AND CONSEQUENCES OF THE DARWINIAN THEORIES.

THE PHILOSOPHIC PROBLEMS.

Although, in accordance with the requirements of the task before us, we have to restrict ourselves to giving the results of natural science only in their general outlines, still we believe that we have not overlooked any essential result which is of importance to the question of the origin of species and of man. We have now finished our scientific review; and the conclusion to which we see ourselves brought is that natural science, in its investigation of the origin of species, has arrived at nothing but problems which it is not able to solve. There is a very great probability of an origin of species, at least of the higher organized species, through descent; but whether through descent by means of gradual development or of metamorphosis of germs, or whether with one group of organisms it is in this way, with another in that, is not yet decided. The attempt to explain their entire origin exclusively by the selection theory, must be regarded as a failure; all indications rather show that, supposing the descent principle correct, the deciding agencies which formed new species did not approach the old species out of which the new ones originated from {109} without, but that they originated or were already in existence within them.

But what these agencies were, natural science is at present unable to state; and not only those scientists who reject every idea of a descent, but also those who are favorable to the ideas of descent and of evolution, rejecting only the selection theory, are at one in silent or open acknowledgment of this limit of our knowledge, be it permanent or temporary.

But now the question arises: does the search after these agencies henceforth remain the exclusive task of natural science, and have we therefore simply to wait and see whether it will succeed in finding them?

or have we to look for the answer to these questions, which natural science can no longer give, in another science--namely, philosophy? The first question we will have to answer in the affirmative, the second in the negative. It is certainly understood that _metaphysical_ principles must underlie all _physical_ appearances; and the right to define these principles, so far as they can be known, is willingly conceded to philosophy by the scientists, with the exception of those of materialistic and naturalistic tendencies. This mutual re-approaching of philosophy and natural science is one of the most gratifying, and, to both, most fruitful evidences of the intellectual work of the present generation. But these metaphysical principles themselves become cognizable only when the physical effects, whose cause they are, become accessible to our knowledge; and every attempt to find them _a priori_, or only to extend them _a priori_, will always fail through the opposition of empirical facts; or even if this attempt accommodates itself to the existing state of knowledge at a given time, it will always be overcome by the {110} progress of the empirical sciences. In the most favorable case, it can claim the value of a hypothesis which has to be put to the proof, whether it can be empirically confirmed and whether we can successfully operate with it in knowing the world of realities. But herewith it leaves the realm of pure philosophy, and makes the question of its right to exist dependent upon the decision of natural science.

Since the decline of the doctrines of nature held by Sch.e.l.ling, Steffens, and Hegel, there has come to our knowledge, from the domain of philosophy, but one earnest attempt to explain the origin and development of organisms down to the concrete differences between single types, cla.s.ses, and even orders and families, from one single metaphysical principle; and this attempt has been made by an antagonist of the descent doctrine. K. Ch.

Planck, in "Seele und Geist, oder Ursprung, Wesen und Thatigkeitsform der physischen und geistigen Organisation von den naturwissenschaftlichen Grundlagen aus allgemein fa.s.slich entwickelt" ("Soul and Spirit, or Origin, Nature, and Form of Activity of Physical and Intellectual Organization, Clearly Developed from a Scientific Basis"), Leipzig, Fues, 1871, and in "Wahrheit und Flachheit des Darwinismus" ("Truth and Plat.i.tude of Darwinism"), Nordlingen, Beck, 1872, makes the "inner concentration" the moving principle of the whole development of the world. He thinks that what belongs to the organism and to the soul has originated and developed up to man and his spiritual nature thus: that the creating centrum of the earth produces individual centra on its periphery, which tend more and more to bring into view the principle of {111} centralization, in its contrast to the purely peripheral form of existence, until it reaches its goal in man, with his centralizing spirit. We have no reason to reject the idea of a principle of concentration in the world and its parts; it is confirmed by observation, and shows itself fruitful in many respects. But in spite of the many ingenious and often suggestive ideas in the works of Planck, we have some doubt about a system which tries to explain the whole concrete abundance of the richness of formations and life-forms in the world, rising higher and higher up to spiritual existence and moral action, from the single idea of concentration, and makes this principle the mystical and mysteriously acting cause of a whole world and its contents. We doubt at the outset the success of this argument. We have especially the strongest objections to a philosophical system which submits all the contending physical theories of the present to the measure of that concentration principle, and from these purely metaphysical reasons takes side exclusively with the one or the other of the theories, or establishes new theories--from the theories of atoms and ether, of light and heat, down to geological questions as to whether universal revolutions of the world or a continual development took place. The solution of all these questions, in their full extent, we do not attribute to philosophy, but to natural science; although to a natural science which permits philosophy to define the ideas with which it operates and the general principles to which it comes. For this renunciation--which philosophy, however, can not at all escape--it will be the more richly rewarded in this, that it obtains the more certainly for its own work sure and sifted material. But all attempts which can not {112} submit to this renunciation, give only an apparent right to that view which Albert Lange, in his "History of Materialism,"

defends, when he banishes speculative philosophy to the realm of imagination.

But in rejecting philosophy in the question of the causes of the development and organization of the organic kingdoms, we did not reach the end of the philosophic problems with which we are confronted. This whole question is itself only a segment of the problems before which we stand, and leads of necessity to other questions.

Already within the series of development of the organic world, so far as it is investigated by natural science, we have found and named a point (at the end of -- 1, Chap. II, Book I), where the competency of pure natural science comes to an end, and the question arises whether another source of knowledge--_i.e._, even philosophy--can not take up the investigation where natural science completes its task. This point was the _origin of self-consciousness_ and of _free moral self-determination_; consequently, the origin of that which makes man _man_. Going still farther back on the temporal and ideal scale of organic beings, we arrive at another point, which natural science no longer can explain, and that is the _origin of sensation_ and of _consciousness_. With the appearance of sensation and consciousness, the _animal world_ came into existence. Moreover, the whole scientific question as to the origin and development of species, so far as we have hitherto treated it, started from initial points where the organic and life already existed; it, therefore, leads of necessity to the further question as to _the origin of the organic and of life itself_. D. F.

Strauss, {113} in his "Postscript as Preface," thus clearly and simply characterizes these still unfilled blanks in the evolution theory: "There are, as is well known, three points in the rising development of nature, to which the appearance of incomprehensibility especially adheres (to speak more categorically: which have not been explained thus far by anybody). The three questions are: How has the living sprung from that which is without life? the sentient (and conscious) being from that which is without sensation? that which possesses reason (self-consciousness and free will) from that which is without reason?--questions equally embarra.s.sing to thought." But even the question as to the origin of the organic and of life can not be discussed without an investigation, leading us farther back to the question as to _the elements of the world_ in general. The _doctrine of atoms_, and the _mechanical view of the world_, are the scientific evidences of the efforts in this direction.

So far as the attempts to solve these four questions start from the results of natural science and, from this starting-point of the known, try to solve the unknown, we will have to a.s.sign them in the encyclopaedic cla.s.sification of the sciences, to that department of philosophy which treats the doctrines of nature; and since our whole investigation starts from the Darwinian theories, and only tries to treat of what is properly connected with them, the attempts to solve these four questions offer themselves as the _naturo-philosophic supplements of the Darwinian-theories_.

After concluding our treatment of them, we shall have to speak of still another view, which presupposes all these attempts at solution to be wholly or nearly {114} successful, and draws an inference from them which no longer belongs to the realm of natural science, but is a purely _metaphysical_ hypothesis; it is the _abolition of the idea of design in nature_. In connection with this, finally, we shall have to discuss the name which this view has lately a.s.sumed, viz: "_Monism_."

Whatever further questions may arise, belong either to the special subdivisions of natural science and philosophy, or to theological and ethical problems.

* * * * * {115}

CHAPTER I.

THE NATURO-PHILOSOPHIC SUPPLEMENTS OF THE DARWINIAN THEORIES.

-- 1. _The Origin of Self-Consciousness and of Free Moral Self-Determination._

If sensation, and its most developed form, consciousness, is a reflex of the material in something immaterial, which feels itself a unit in contrast to the material, and, where sensation rises into consciousness, is opposed as a unit to the material--self-consciousness again is the reflex of this sentient and conscious subject in a new and still higher immaterial unity; and this again makes this sentient and conscious subject, together with the sum of its feelings and ideas, its object, changing it from a sentient and conscious subject into a felt and presented object. Therefore it is clear, and will be the result of all thought upon these concepts, that as with sensation and consciousness, so also with self-consciousness, something new always comes into existence--a higher category of being, different from the merely material. The first is the form of being of the animal world; the latter that of mankind.

It is exactly the same with the first appearance of voluntary movement, and again with that of free moral self-determination. The reaction of the sentient subject upon his sensations is something qualitatively different from the purely mechanical and physical action and {116} reaction of pure matter; although, in order to understand the possibility of a sensation as well as of a voluntary movement, we must admit that the physical qualities of matter must be such as to afford a basis and condition for sentient and reacting beings. That reaction is the reaction of something immaterial upon the material, even if it is entirely caused by the material and bound to the material. Now, with free moral self-determination a new subject comes into existence and activity in the individual, which makes that subject, reacting upon mere sensations and ideas, its object, and, as a new immaterial subjective unity, acts determiningly upon that subject which has just become object. This new subject, considered from the side of its receptivity, we call _self-consciousness_; from the side of its spontaneity, _free moral self-determination_. Whether we consider this freedom predetermined or not, does not at all alter the described fact and the qualitative difference between the form of human moral agency and that of purely animal spontaneity. For even those advocating determination must admit that the morally acting subject distinguishes itself from its object, and does not take its motives to action from the material and from the instinctive life which is bound to the sensual and dependent on it.

Now it is true that all these circ.u.mstances in organized individuals which serve self-consciousness and free moral self-determination as their condition, presupposition, and basis, all the dispositions of the soul and the manifestations of life found in the animal world, will be worthy of the closest attention even on this account: because they form the basis, the condition, and (if self-consciousness and freedom are once present) an essential {117} part of the contents and object of self-consciousness and moral self-determination. But where the origin of man is discussed, the central point of the investigation is no longer the enumeration of those activities of the soul of man whose a.n.a.logies we also find in the animal world, but rather in the answer to the question as to how that entirely new manifestation, self-consciousness and moral self-determination, came into existence or could have originated. This question is the more decidedly the central point of the investigation, since this new form, when once in existence, has for its object not only what already appears in the life of the soul of animals, but also receives a new object, which can only be an object of self-consciousness and of moral self-determination, and not of mere consciousness and instinctive life. These new objects are the ideas leading up to the conception of G.o.d and moral ideals.

Now this very question as to the origin of self-consciousness and of free moral self-determination is wholly misjudged as to its importance, and given remarkably little attention by those evolutionists who are well versed in the realm of natural science. The question as to the origin of self-consciousness is either entirely ignored--as if self-consciousness must originate wholly by itself, if only those first steps of an intellectual and social life which the animal world also shows, are once present and properly developed--or the solution is put aside with the most superficial a.n.a.logies. The question regarding free moral self-determination, on the other hand, is either likewise ignored, and for the same reasons, or it is supposed that it must fail of itself, if {118} only this self-determination is explained in a deterministic way.

It is true, Darwin devotes several chapters of his work, "Descent of Man,"

to a comparison of the intellectual powers of man with those of animals, and these chapters are full of the most interesting facts and comparisons; but although his work comprises two volumes, he devotes to the origin of self-consciousness, individuality, abstraction, general ideas, etc., only a single page, and justifies his brief treatment with the a.s.sertion that the attempt at discussing these higher faculties is useless, because hardly two authors agree in their definitions of these terms. What he says about self-consciousness is really contained in two sentences, namely: "But how can we feel sure that an old dog with an excellent memory and some power of imagination, as shown by his dreams, never reflects on his past pleasures or pains in the chase? This would be a form of self-consciousness." On the other hand, as Buchner has remarked in his "Lectures about Darwin's Theory": "How little can the hard-working wife of a degraded Australian savage, who hardly ever uses abstract words, and can not count above four, how little can such a woman exert her self-consciousness, or reflect on the nature of her own existence!" And in Darwin's _resume_ of his chapters on the intellectual powers of man and animals, he says, on page 126: "If it could be proved that certain high mental powers, such as the formation of general concepts, self-consciousness, etc., were absolutely peculiar to man, which seems extremely doubtful, it is not improbable that these qualities are merely the incidental results of other highly-advanced intellectual faculties: {119} and these again mainly the result of the continued use of a perfect language."

If Darwin is thus not able to show us in the animal world a single real a.n.a.logy which at all approaches self-consciousness, and, in order to supply this want, must have recourse to the purely hypothetical _possibility_ that it is not certain whether an old hunting-dog does not reflect upon the past joys of the chase; if by the uncertainty of the expression that self-consciousness might be an "_accompanying_" result of other faculties, he nevertheless gives us to understand that he can not find the _sufficient_ cause of the origin of self-consciousness in those other faculties; and, finally, if he closes the last mentioned quotation with a sentence which has for its premise the wholly illogical thought that language might have been able to reach "a high state of development" before the origin of self-consciousness and without its a.s.sistance: then, indeed, the result of all this certainly is that he has given no adequate consideration to the specific nature of self-consciousness. It is only under this supposition that it is possible for him to say: "Nevertheless, the difference in mind between man and the higher animals, great as it certainly is, is one of degree and not of quality." The authors may possibly not agree in the definitions of the idea of self-consciousness--we ourselves perhaps are only an additional example in confirmation of this fact--; but whatever the definition may be, the fact itself remains, that self-consciousness does not stand as one of the intellectual faculties beside the others and coordinate with them, but, as an entirely new form of being, introduces a qualitatively new and valuable factor into the subject.

That which precedes the {120} origin of self-consciousness--the purely conscious and not yet self-conscious life of the soul, as it shows itself with higher animals, especially with mammals--_may_ have been the necessary condition and requirement for the origin of self-consciousness. It certainly _has_ been so; and from this point of view, all these psychological studies of animals and psycho-physical investigations which are a favorite object of modern science, have a high value; but what has been called into existence by _means_ of conditions is not on that account the _product_ of those conditions. This very fact is one of the greatest mistakes of most of the modern evolution theories: that very often--and especially where they wish to draw metaphysical conclusions from their scientific results or hypotheses--they confound condition and basis with cause.

Now it appears to us that, in quite an a.n.a.logous way, Darwin overlooks or contests the fact that with _free moral self-determination_ something specifically new comes into existence. He certainly discusses the origin of the moral qualities of man more in detail than he does the origin of his intellectual qualities. He derives them, in their first beginnings, from the fixity, transmission and increase of the _social_ impulses and instincts. These, being the basis of the whole moral development, and leading in their more mature form to love and to sympathy, originated by natural selection; and the other moral qualities, such as moral sense and conscience, progressed more by the effect of custom, by the power of reflection, instruction, and religion, than by natural selection. Higher and lower, common and special, permanent and transitory instincts come into collision {121} with one another. The dissatisfaction of man when any of the lower, special, and transitory instincts have overcome the higher, common and permanent, and the resolution to act differently for the future, is _conscience_. Darwin considers that one a _moral being_ who is capable of comparing with one another his past and future actions and motives, of approving some of them and of disapproving others; and the fact that man is the only creature who can with certainty be ranked as a moral being is, according to Darwin, the greatest of all differences between man and animals.

Here, again, the whole central point of the investigation as to the origin of man does not lie in the question of the origin of the instincts between which the moral subject, acting in moral self-determination, has to choose.

For it is clear that the beginnings of these instincts are also present in the animal world. But the main question is, how did this faculty and necessity of choosing, this conscience and responsibility, this "moral sense," as Darwin calls it, originate? Now to this question we have a plain answer in the before-mentioned utterances of Darwin: It originated not as a _product_ of the social instincts--it only has these instincts for its preceding condition, object and instrument; but it originated as a product of other agencies, which act upon these impulses and instincts, operate with them, choose between them; and as these other agencies Darwin mentions the high development of the intellectual powers. That this is his opinion, we can clearly see from an expression with which he introduces his essay on the origin of "moral sense": "The following proposition seems to me in a high degree probable--namely, that {122} any animal whatever, endowed with well-marked social instincts, would inevitably acquire a moral sense or conscience, _as soon as its intellectual powers had become as well, or nearly as well developed, as in man_." These intellectual powers which moral feeling and conscience require at their birth, are certainly, according to Darwin the power to distinguish oneself as subject from one's impulses and instincts, and to choose between them; _i.e._, self-consciousness. We shall have to admit fully this intimate connection between moral self-determination and self-consciousness; but we must admit, at the same time, that moral self-determination--this new form of activity in which moral activity distinguishes itself from all _merely_ instinctive activity--finds its sufficient explanation in the previous stage of the animal world as little as self-consciousness; and that moral self-determination has the condition and presupposition, but not the cause, of its existence in that which is also found in the previous stage of the animal world. The proof that the origin of moral self-determination finds its sufficient explanation in that which the previous stage of the animal world also has, would appear to have been given by Darwin only when he had succeeded in explaining the origin of self-consciousness from animal intelligence; but that he did not succeed in it, we think we have clearly shown. On the other hand, we willingly admit that the study of the social and all other instincts and impulses which are common to man and animals, and which in man form the object and instrument of his moral activity, has for us the highest interest, inasmuch as the only problem is to explain the conditions and prerequisites of moral self-determination--or, historically speaking, the conditions {123} and prerequisites of the origin of morally acting beings. Furthermore we have to say here also that condition and prerequisite are not identical with cause, and it is precisely the _cause_ of moral responsibility and of the origin of such morally responsible beings, which has not yet been discovered by the Darwinian theory.

The followers of Darwin enter still less into the discussion of the question as to the origin of self-consciousness and of moral self-determination. Hackel--who, in his "Natural History of Creation" and in his "Anthropogeny," expounds his whole evolution theory in all its antecedent conditions and consequences--has, indeed, much to say of the different faculties of the soul of man and animals. He traces these faculties in the case of man down to the lowest state of the most degraded races, and in the case of animals from the kermes up to the bee, from the lancelet-fish to the dog, ape, elephant and horse; and he also treats of the so-called _a priori_ knowledge which "arose only by long-enduring transmission, by inheritance of acquired adaptations of the brain, out of originally empiric or experiential knowledge _a posteriori_," (Vol. II, 345). But we look in vain in his works for a treatment of the question as to the origin of the Ego--of self-consciousness. Nowhere does he enter into the a.n.a.lysis of the psychological ideas; he only compares the psychical utterances of different creatures, and thinks the whole problem solved when he says: "The mental differences between the most stupid placental animals (for instance, sloths and armadillos) and the most intelligent animals of the same group (for instance dogs and apes) are, at any rate, much more considerable than the differences in the {124} intellectual life of dogs, apes, and men." Or: "If these brutish parasites are compared with the mentally active and sensitive ants, it will certainly be admitted that the psychical differences between the two are much greater than those between the highest and lowest mammals--between beaked animals, pouched animals and armadillos, on the one hand, and dogs, apes, men, on the other." The fact that in the human individual consciousness and self-consciousness are gradually developed, is to him a proof that in the organic kingdom also consciousness and self-consciousness came into existence gradually, and, indeed, hand-in-hand with the development of the nervous system; and with this result he thinks that he has relieved himself from the task of showing the "how" of the origin of self-consciousness. This becomes clearly evident from a remark about the origin of consciousness, in his "Anthropogeny,"

where he says that, if DuBois-Reymond had thought that consciousness is developed, he would no longer have held its origin to be a thing beyond the limits of human capacity. Hackel likewise seems to regard the question of the origin of moral self-determination as solved or rejected, if only freedom is denied--which, indeed, is repeatedly done by him.

A similar defect in the treatment of this question by evolutionists we find in the works of Oscar Schmidt, Gustav Jager, and others. Even Emil DuBois-Reymond, who, in his celebrated and eloquent lecture on "The Limits of the Knowledge of Nature," given before the a.s.sembly of scientists at Leipzig, 1872, a.s.serts so energetically that the origin of sensation and consciousness is inexplicable (see next section), seems to {125} take the origin of self-consciousness for granted, and as needing no further explanation, if only consciousness is once present.

Since, then, the scientists leave us without a sufficient answer to the question respecting the origin of self-consciousness and of moral self-determination, we shall have to turn to the philosophers. Here, indeed, we find rich definitions and genetic a.n.a.lyses, but none that lead us any farther than to the information that consciousness is the necessary condition of self-consciousness; that animal instinct is the necessary antecedent condition of moral self-determination. Yet in the works of these very philosophers who are inclined to a mechanical and "monistic" view of the world, we find that they directly avoid the question as to the origin of self-consciousness and of moral self-determination. As soon as they are led near it, in the course of reasoning in their works, they suddenly turn aside again to the quite different questions of the connection between brain and soul, between physical and psychical, external and internal processes, etc. Evidently they feel that with this question they have arrived at the weak point of their system. That here is a weak point, we clearly see in the case of D. F. Strauss, a leading advocate of modern naturalism, and the greatest philosophic scholar of that school. It is true, in his "Postscript as Preface," as we saw before, he mentions the origin of self-consciousness as one of the points which need special explanation; but he seems to have made this acknowledgment more with the purpose of showing that DuBois-Reymond, in admitting the origin of self-consciousness to be explainable, has no longer any reason to contest the explicability of the {126} origin of sensation and consciousness; for in his work on "The Old Faith and the New," he did not enter into that question at all. On the other hand, he makes in his last-mentioned work a remarkable confession. In answering the question--how do we determine our rule of life?--he comes to speak of the position of man in nature, traces a law of progress in nature, and says: "In this c.u.mulative progression of life, man is also comprised, and, moreover, in such wise that the organic plasticity of our planet (provisionally, say some naturalists, but that we may fairly leave an open question) culminates in him. _As nature can not go higher, she would go inwards._ 'To be reflected within itself,' was a very good expression of Hegel's. Nature felt herself already in the animal, but she wished to know herself also." But still stronger is the following expression: "_In man, nature endeavored not merely to exalt, but to transcend herself._" In -- 1, Chap. II, we shall have to speak of this important acknowledgment of teleology in nature, which such an antagonist of teleology as Strauss makes in the above-quoted remarks about a progress in nature and a will of nature; but here we are more interested in the equally remarkable acknowledgment of the fact that man can not be explained from nature alone--that he is something which transcends nature. For that (according to Strauss) nature, in originating man, not only _intended_ to transcend herself, but really did transcend herself and, that she succeeded in her intention, we can infer from the moral precept which Strauss gives: "Do not forget for a moment, that thou art human; not merely a natural production."

The result of our investigation, therefore, is that {127} with self-consciousness and free moral self-determination something specifically new came into existence which had its antecedent condition in a previous state of existence, but has not yet found its sufficient explanation in this antecedent state.

-- 2. _The Origin of Sensation and of Consciousness._

The limits of our knowledge show themselves still more clearly in the attempts to explain the origin of consciousness and its lowest form--sensation. Self-consciousness is without doubt ideally nearer to consciousness in this, that both are an immaterial activity; and yet we found no demonstrable bridge which leads from consciousness to self-consciousness. Still broader is the gulf between the material and the immaterial, between the unconscious and the conscious,--or, to describe the two realms with names which bring them nearest together, between that which is without sensation and that which has sensation: a gulf to bridge which philosophy also has vainly exerted its utmost efforts, as has been well known since the "supernatural a.s.sistance" of Descartes and the "preestablished harmony" of Leibnitz. Wherein lies the real necessity that there should be sensation? How does the material become something that is felt? What is the demonstrable cause (not the condition, but the cause) of a sentient subject? To these questions, every science up to the present day lacks an answer. As is well known, DuBois-Reymond, in his previously-mentioned lecture upon "The Limits of our Knowledge of Nature,"

declares the origin of sensation and of consciousness to be one of two limits, beyond {128} which we have not only to say "_ignoramus_," but "_ignorabimus_."

_In abstracto_, we might think of two attempts at bridging over this gulf: the first one is that we try to transform sensation itself into something material, and the other is that we attribute sensation also to that which, according to our observation, seems to be without sensation; namely, to matter and its elements, the atoms. Both of these attempts have been made--the former by D. F. Strauss in his "The Old Faith and the New," and by the English philosopher, Herbert Spencer, in his "First Principles of Philosophy;" the latter, first pointed out by Schopenhauer, was taken up and farther developed by Zollner in his work, "Ueber die Natur der Kometen"

("Nature of the Comets"), Leipzig, Engelmann, 1872, and with special acuteness by an "Anonymus" in the work: "Das Unbewusste von Standpunkt der Physiologie und Descendenztheorie" ("The Unconscious from the Standpoint of Physiology and Descent Theory"), Berlin, Duncker, 1872.

Strauss says, in the previously-mentioned work: "If, under certain conditions, motion is transformed into heat, why may it not, under other conditions, be transformed into sensation?" And Herbert Spencer says, in his "First Principles of Philosophy," (page 217): "Various cla.s.ses of facts thus unite to prove that the law of metamorphosis, which holds among the physical forces, holds equally between them and the mental forces. Those modes of the unknowable which we call motion, heat, light, chemical affinity, etc., are alike transformable into each other, and into those modes of the unknowable which we distinguish as sensation, {129} emotion, thought: these, in their turns, being directly or indirectly retransformable into the original shapes."

But motion--even the finest material motion, that of ether, (which, in consequence of the very important discovery of the conservation of force and of the mechanical equivalent of heat, made by Robert von Mayer, at present is taken to be heat)--is so decidedly a material process, the sensation of motion is so decidedly a reflex of the material in something immaterial, that the a.s.sertion of a transformation of motion into sensation seems to us only to change the point of view, and not to explain the difference, but to efface it. And we think that the appeal of Strauss from his contemporaries, who do not understand him, to posterity, who would understand him better and esteem him, has but little prospect of being operative.

If that which has sensation and that which has it not, are to be brought genetically near one another, and hence the difference between the two at the point where the lowest sentient being has found its first existence, is to be made void or at least bridged over, then it is much more reasonable, and also in the line of Strauss's solution, to deny the difference between that which has sensation and that which has it not, and to do this in the sense in which we also declare that to be sentient which we have hitherto been accustomed to regard as without sensation; and we should likewise attribute sensation to the original elements of the world, be they called atoms or whatever one may wish. This is done by Zollner and by the before mentioned "Anonymus." This conclusion is logical; it is even the only possible conclusion, if we once start from the axiom that the new, which comes {130} into existence, must necessarily be explainable from agencies previously active, and known to or imagined by us through abstractions and hypotheses. Zollner is certainly right when, in his work which appeared before the lecture of DuBois-Reymond, he puts the alternative, "either to renounce forever the conceivableness of the phenomena of sensation, or hypothetically to add to the common qualities of matter one more, which places the simplest and most elementary transactions of nature under a process of sensation, legitimately connected with it;" as also when he says (page 327): "We may regard the intensity of these sensations (of matter) as little and unimportant as we wish; but the hypothesis of their existence is, according to my conviction, a necessary condition, in order to comprehend the really existing phenomena of sensation in nature." Only we shall do well to choose the first alternative for the present, and, with DuBois-Reymond, answer the question as to the explanation of the origin of sensation with an "_ignoramus_"; indeed, we shall take a surer road with his "_ignorabimus_" than by a plunge into that bottomless ocean of hypotheses--in spite of the protest of Hackel, who (Anthrop., page XXI) sees that scientist who has the courage to admit the limits of our knowledge, on account of this "_ignorabimus_", walking in the army of the "black International", and "marshalled under the black flag of the hierarchy," together with "spiritual servitude and falsehood, want of reason and barbarism, superst.i.tion and retrogression", and fighting, "spiritual freedom and truth, reason and culture, evolution and progress."

For a solution of the question which simply denies all sharply-marked differences in the world, and explains {131} the new, which comes into existence with sensation, by the a.s.sertion that this new element is not new, but was already present, and that it exists everywhere, only we do not see it everywhere,--such a solution seems to us not to be the true way to interpret the problem of the sphinx. Even Ed. von Hartmann seems to infringe the impartiality of the true observer, when, in his "Philosophy of the Unconscious," he attributes sensation to plants. But when Zollner says (p. 326): "_All the labors of natural beings_ [and, as the connection indicates, of all, even of inorganic natural beings] are determined by like and dislike;" and when "Anonymus" attributes sensation to all atoms and to all complexities composed of them, even to stone, then all reasonable conception of natural things and processes certainly vanishes into thin air.

It will be remembered, however, that in treating the question of the origin of self-consciousness, although we were not able to solve the problem, nevertheless we had to ascribe high value to the investigation of all psychical processes on the low stage of sensation and consciousness, since they show us not the cause, but the condition and basis, of self-consciousness. Likewise, in the question as to the origin of sensation and of consciousness, although we are not able to solve it, we will willingly admit that we observe, even in that which has no sensation, qualities and processes which furnish the absolutely necessary condition and basis for sensation. For the same reason, we will also admit the manifold a.n.a.logies of sensation which we observe in that which is without sensation. The whole system of symbols in nature which fills our treasury of words and penetrates, in a {132} thousandfold way, our scientific and popular, our poetical and prosaic speech, our thoughts and feelings, bears witness to the fact that that which is without sensation is also a preparatory step to sensation, and feeling both active and pa.s.sive springs from it. However, a preparatory step, as such, is not necessarily the cause; and the fact and the acknowledgment of a correlation is not on that account an explanation.

-- 3. _The Origin of Life._

The third problem to be solved is the origin of life. As is well known, Darwin himself makes no attempt at explaining this problem, but is satisfied with the idea that life was infused into one or a few forms by the Creator ("Origin of Species," 6 ed., p. 429). His investigations and theories only begin where organic life, in its first and lowest forms, is already in existence.

But lately there have been made, in the realm of the organic, discoveries of beings which take the lowest conceivable round on the ladder of organisms, and which in their form and structure are so simple that from them to the inorganic there seems to be but a short step. We can no longer mention as belonging to the bridges which are said to lead from the organic world to the inorganic, the often-named _bathybius_, discovered by Huxley, and so strongly relied upon for the mechanical explanation of life--a slimy net-like growth, which covers the rocks in the great depths of the ocean.

For after scientists like K. E. von Baer and others had already declared it probable that this bathybius is only a precipitate of organic relics, no less a person than the discoverer of the bathybius, in the "Annals of Natural History," 1875, {133} and in the "Quarterly Journal of Microscopical Science," 1875, has suggested that the whole discovery is but gypsum, which was precipitated in a gelatinous condition. Likewise the utterances concerning the simplicity and lack of structure of the lowest organisms, are to be accepted only with great reservation; for most of these organisms show very differently and very distinctly stamped structures; of this fact, anyone may easily convince himself, who has had the opportunity of observing with the microscope low and lowest organisms, and to admire their striking and manifold forms. Nevertheless, there are monera whose structure seems to be nothing but a living clod without kernel and cover, and which in that respect represent the lowest conceivable form of organic being and life.

Now, relying on these discoveries, as well as upon the successful demonstration, by inorganic means, of organic acids in chemistry, and starting from the supposition that the first appearance of life must necessarily be explained by those agencies which are already active in the inorganic nature, many scientists have attempted the so-called _mechanical explanation of life_. This attempt has been made most logically and systematically by Hackel. He says that organic _matter_, organic _form_, and organic _motion_, in the lowest stages of the organic, which are almost the only ones to be taken into consideration when the problem of the origin of life is discussed, contain nothing at all which does not also pertain to the inorganic. In his opinion, organic _matter_ is an alb.u.minous carbon combination, of which we have to presuppose that, like all chemical combinations, under certain physical and chemical conditions it can also arise in the realm {134} of the inorganic in a purely chemical and mechanical way. Organic _form_ which, in its lowest stages, is so simple, like the moneron and the bathybius, and which stands still lower than a cell, is, moreover, something which there is no difficulty in explaining from inorganic matter. Finally, organic _motion_ which alone is the last and lowest characteristic of the organic in its lowest stage--in which the process of life properly consists, and in which, therefore, we have to recognize the _punctum saliens_ of the whole question--is only an increase and complication of the merely mechanical motion of the inorganic, likewise explainable by mechanical causes. This view Hackel expounds in the thirteenth and partly also in the first chapter of his "Natural History of Creation," and explains the origin of the first and most simple organic individuals either through what he calls _autogony_ in an inorganic fluid, or through _plasmogony_ in an organic fluid--a plasma or protoplasma. In fact, according to him, the only correct idea is that all matter is provided with a soul, that inorganic and organic nature is one, that all natural bodies known to us are equally animated, and that the contrast commonly drawn between the living and the dead world does not exist. This is but a repet.i.tion, in a more rhetorical way, of the same idea which "Anonymus" expressed in discussing the question as to the origin of sensation.