without doing violence to truth, this could only take place by placing the whole _necessity_ in the _acting and doing_ (_Operari_), and the whole _freedom_ in the _being and nature_ (_Esse_). Thereby a riddle is solved which is as old as the world, simply because it has hitherto always been held upside down and the freedom persistently sought in the _Operari_, the necessity in the _Esse_. I, on the contrary, say: Every being without exception _acts_ with strict necessity, but it _exists_ and is what it is by virtue of its _freedom_. Thus with me freedom and necessity are to be met with neither more nor less than in any earlier system; although now one and now the other must be conspicuous according as one takes offence that _will_ is attributed to processes of nature which hitherto were explained from necessity, or that the same strict necessity is recognised in motivation as in mechanical causality. The two have merely changed places: freedom has been transferred to the _Esse_, and necessity limited to the _Operari_.
In short, _Determinism_ stands firm. For fifteen hundred years men have wearied themselves in vain to shake it, influenced by certain crotchets, which are well known, but dare scarcely yet be called by their name. Yet in accordance with it the world becomes a mere puppet‐show, drawn by wires (motives), without it being even possible to understand for whose amusement. If the piece has a plan, then fate is the director; if it has none, then blind necessity. There is no other deliverance from this absurdity than the knowledge that the _being and nature_ of all things is the manifestation of a really _free will_, which knows itself in them; for their _doing and acting_ cannot be delivered from necessity. To save freedom from fate and chance, it had to be transferred from the action to the existence.
As now necessity only affects the phenomenon, not the thing in itself, _i.e._, the true nature of the world, so also does _multiplicity_. This is sufficiently explained in § 25 of the first volume. I have only to add here one remark in confirmation and illustration of this truth.
Every one knows only _one_ being quite immediately—his own will in self‐ consciousness. Everything else he knows only indirectly, and then judges it by analogy with this; a process which he carries further in proportion to the grade of his reflective powers. Even this ultimately springs from the fact that there really is _only one being_; the illusion of multiplicity (_Maja_), which proceeds from the forms of external, objective comprehension, could not penetrate to inner, simple consciousness; therefore this always finds before it only one being.
If we consider the perfection of the works of nature, which can never be sufficiently admired, and which even in the lowest and smallest organisms, for example, in the fertilising parts of plants or in the internal construction of insects, is carried out with as infinite care and unwearied labour as if each work of nature had been its only one, upon which it was therefore able to expend all its art and power; if we yet find this repeated an infinite number of times in each one of innumerable individuals of every kind, and not less carefully worked out in that one whose dwelling‐place is the most lonely, neglected spot, to which, till then, no eye had penetrated; if we now follow the combination of the parts of every organism as far as we can, and yet never come upon one part which is quite simple, and therefore ultimate, not to speak of one which is inorganic; if, finally, we lose ourselves in calculating the design of all those parts of the organism for the maintenance of the whole by virtue of which every living thing is complete in and for itself; if we consider at the same time that each of these masterpieces, itself of short duration, has already been produced anew an innumerable number of times, and yet every example of a species, every insect, every flower, every leaf, still appears just as carefully perfected as was the first of its kind; thus that nature by no means wearies and begins to bungle, but, with equally patient master‐hand, perfects the last like the first: then we become conscious, first of all, that all human art is completely different, not merely in degree, but in kind, from the works of nature; and, next, that the working force, the _natura naturans_, in each of its innumerable works, in the least as in the greatest, in the last as in the first, _is immediately present whole and undivided_, from which it follows that, as such and in itself, it knows nothing of space and time. If we further reflect that the production of these hyperboles of all works of art costs nature absolutely nothing, so that, with inconceivable prodigality, she creates millions of organisms which never attain to maturity, and without sparing exposes every living thing to a thousand accidents, yet, on the other hand, if favoured by chance or directed by human purpose, readily affords millions of examples of a species of which hitherto there was only one, so that millions cost her no more than one; this also leads us to see that the multiplicity of things has its root in the nature of the knowledge of the subject, but is foreign to the thing in itself, _i.e._, to the inner primary force which shows itself in things; that consequently space and time, upon which the possibility of all multiplicity depends, are mere forms of our perception; nay, that even that whole inconceivable ingenuity of structure associated with the reckless prodigality of the works upon which it has been expended ultimately springs simply from the way in which things are apprehended by us; for when the simple and indivisible original effort of the will exhibits itself as object in our cerebral knowledge, it must appear as an ingenious combination of separate parts, as means and ends of each other, accomplished with wonderful completeness.
The _unity of that will_, here referred to, which lies beyond the phenomenon, and in which we have recognised the inner nature of the phenomenal world, is a metaphysical unity, and consequently transcends the knowledge of it, _i.e._, does not depend upon the functions of our intellect, and therefore can not really be comprehended by it. Hence it arises that it opens to the consideration an abyss so profound that it admits of no thoroughly clear and systematically connected insight, but grants us only isolated glances, which enable us to recognise this unity in this and that relation of things, now in the subjective, now in the objective sphere, whereby, however, new problems are again raised, all of which I will not engage to solve, but rather appeal here to the words _est quadam prodire tenus_, more concerned to set up nothing false or arbitrarily invented than to give a thorough account of all;—at the risk of giving here only a fragmentary exposition.
If we call up to our minds and distinctly go through in thought the exceedingly acute theory of the origin of the planetary system, first put forth by Kant and later by Laplace, a theory of which it is scarcely possible to doubt the correctness, we see the lowest, crudest, and blindest forces of nature bound to the most rigid conformity to law, by means of their conflict for one and the same given matter, and the accidental results brought about by this produce the framework of the world, thus of the designedly prepared future dwelling‐place of innumerable living beings, as a system of order and harmony, at which we are the more astonished the more distinctly and accurately we come to understand it. For example, if we see that every planet, with its present velocity, can only maintain itself exactly where it actually has its place, because if it were brought nearer to the sun it would necessarily fall into it, or if placed further from it would necessarily fly away from it; how, conversely, if we take the place as given, it can only remain there with its present velocity and no other, because if it went faster it would necessarily fly away from the sun, and if it went slower it would necessarily fall into it; that thus only one definite place is suitable to each definite velocity of a planet; and if we now see this solved by the fact that the same physical, necessary, and blindly acting cause which appointed it its place, at the same time and just by doing so, imparted to it exactly the only velocity suitable for this place, in consequence of the law of nature that a revolving body increases its velocity in proportion as its revolution becomes smaller; and, moreover, if finally we understand how endless permanence is assured to the whole system, by the fact that all the mutual disturbances of the course of the planets which unavoidably enter, must adjust themselves in time; how then it is just the irrationality of the periods of revolution of Jupiter and Saturn to each other that prevents their respective perturbations from repeating themselves at one place, whereby they would become dangerous, and brings it about that, appearing seldom and always at a different place, they must sublate themselves again, like dissonances in music which are again resolved into harmony. By means of such considerations we recognise a design and perfection, such as could only have been brought about by the freest absolute will directed by the most penetrating understanding and the most acute calculation. And yet, under the guidance of that cosmogony of Laplace, so well thought out and so accurately calculated, we cannot prevent ourselves from seeing that perfectly blind forces of nature, acting according to unalterable natural laws, through their conflict and aimless play among themselves, could produce nothing else but this very framework of the world, which is equal to the work of an extraordinarily enhanced power of combination. Instead now, after the manner of Anaxagoras, of dragging in the aid of an _intelligence_ known to us only from animal nature, and adapted only to its aims, an intelligence which, coming from without, cunningly made use of the existing forces of nature and their laws in order to carry out its ends, which are foreign to these,—we recognise in these lowest forces of nature themselves that same, one will, which indeed first manifests itself in them, and already in this manifestation striving after its goal, through its original laws themselves works towards its final end, to which therefore all that happens according to blind laws of nature must minister and correspond.
And this indeed cannot be otherwise, because everything material is nothing but just the phenomenal appearance, the visibility, the objectivity of the will to live which is one. Thus even the lowest forces of nature themselves are animated by that same will, which afterwards, in the individual beings provided with intelligence, marvels at its own work, as the somnambulist wonders in the morning at what he has done in his sleep; or, more accurately, which is astonished at its own form which it beholds in the mirror. This unity which is here proved of the accidental with the intentional, of the necessary with the free, on account of which the blindest chances, which, however, rest upon universal laws of nature, are as it were the keys upon which the world‐spirit plays its melodies so full of significance,—this unity, I say, is, as has already been remarked, an abyss in the investigation into which even philosophy can throw no full light, but only a glimmer.
But I now turn to a _subjective_ consideration belonging to this place, to which, however, I am able to give still less distinctness than to the objective consideration which has just been set forth; for I shall only be able to express it by images and similes. Why is our consciousness brighter and more distinct the further it extends towards without, so that its greatest clearness lies in sense perception, which already half belongs to things outside us,—and, on the other hand, grows dimmer as we go in, and leads, if followed to its inmost recesses, to a darkness in which all knowledge ceases? Because, I say, consciousness presupposes _individuality_; but this belongs to the mere phenomenon, for it is conditioned by the forms of the phenomenon, space and time, as multiplicity of the similar. Our inner nature, on the other hand, has its root in that which is no longer phenomenon, but thing in itself, to which, therefore, the forms of the phenomenon do not extend; and thus the chief conditions of individuality are wanting, and with these the distinctness of consciousness falls off. In this root of existence the difference of beings ceases, like that of the radii of a sphere in the centre; and as in the sphere the surface is produced by the radii ending and breaking off, so consciousness is only possible where the true inner being runs out into the phenomenon, through whose forms the separate individuality becomes possible upon which consciousness depends, which is just on that account confined to phenomena. Therefore all that is distinct and thoroughly comprehensible in our consciousness always lies without upon this surface of the sphere. Whenever, on the contrary, we withdraw entirely from this, consciousness forsakes us,—in sleep, in death, to a certain extent also in magnetic or magic influences; for these all lead through the centre. But just because distinct consciousness, being confined to the surface of the sphere, is not directed towards the centre, it recognises other individuals certainly as of the same kind, but not as identical, which yet in themselves they are. Immortality of the individual might be compared to a point of the surface flying off at a tangent. But immortality, by virtue of the eternal nature of the inner being of the whole phenomenon, may be compared to the return of that point, on the radius, to the centre, of which the whole surface is just the extension. The will as the thing in itself is whole and undivided in every being, as the centre is an integral part of every radius; while the peripherical end of this radius is in the most rapid revolution, with the surface, which represents time and its content, the other end, at the centre, which represents eternity, remains in the profoundest peace, because the centre is the point of which the rising half is not different from the sinking. Therefore in the Bhagavad‐ gita it is said: “_Haud distributum animantibus, et quasi distributum tamen insidens, animantiumque sustentaculum id cognoscendum, edax et rursus genitale_” (Lect. 13, 16 vers. Schlegel). Certainly we fall here into mystical and figurative language, but it is the only language in which anything can be said on this entirely transcendent theme. So this simile also may pass. The human race may be imagined as an _animal compositum_, a form of life of which many polypi, especially those which swim, such as _Veretillum_, _Funiculina_, and others, afford examples. As in these the head isolates each individual animal, and the lower part, with the common stomach, combines them all in the unity of one life process, so the brain with its consciousness isolates the human individual, while the unconscious part, the vegetative life with its ganglion system, into which in sleep the brain‐consciousness disappears, like a lotus which nightly sinks in the flood, is a common life of all, by means of which in exceptional cases they can even communicate, as, for example, occurs when dreams communicate themselves directly, the thoughts of the mesmeriser pass into the somnambulist, and finally also in the magnetic or generally magical influence proceeding from intentional willing. Such an influence, if it occurs, is _toto genere_ different from every other on account of the _influxus physicus_ which takes place, for it is really an _actio in distans_ which the will, certainly proceeding from the individual, yet performs in its metaphysical quality as the omnipresent substratum of the whole of nature. One might also say that as in the _generatio æquivoca_ there sometimes and as an exception appears a weak residue of the original _creative power_ of the will, which in the existing forms of nature has already done its work and is extinguished, so there may be, exceptionally, acting in these magical influences, as it were, a surplus of its original _omnipotence_, which completes its work and spends itself in the construction and maintenance of the organisms. I have spoken fully of this magical property of the will in “The Will in Nature,” and I gladly omit here discussions which have to appeal to uncertain facts, which yet cannot be altogether ignored or denied.
Chapter XXVI.(4) On Teleology.
The universal teleology or design of organised nature relative to the continuance of every existing being, together with the adaptation of organised to unorganised nature, cannot without violence enter into the connection of any philosophical system except that one which makes a _will_ the basis of the existence of every natural being; a will which accordingly expresses its nature and tendency not merely in the actions, but already in the _form_ of the phenomenal organism. In the preceding chapter I have merely indicated the account which our system of thought gives of this subject, since I have already expounded it in the passage of the first volume referred to below, and with special clearness and fulness in “The Will in Nature,” under the rubric “Comparative Anatomy.”
The astounding amazement which is wont to take possession of us when we consider the endless design displayed in the construction of organised beings ultimately rests upon the certainly natural but yet false assumption that that _adaptation_ of the parts to each other, to the whole of the organism and to its aims in the external world, as we comprehend it and judge of it by means of _knowledge_, thus upon the path of the _idea_, has also come into being upon the same path; thus that as it exists _for_ the intellect, it was also brought about _by_ the intellect. We certainly can only bring about something regular and conforming to law, such, for example, as every crystal is, under the guidance of the law and the rule; and in the same way, we can only bring about something designed under the guidance of the conception of the end; but we are by no means justified in imputing this limitation of ours to nature, which is itself prior to all intellect, and whose action is entirely different in kind from ours, as was said in the preceding chapter. It accomplishes that which appears so designed and planned without reflection and without conception of an end, because without idea, which is of quite secondary origin. Let us first consider what is merely according to rule, not yet adapted to ends. The six equal radii of a snowflake, separating at equal angles, are measured beforehand by no knowledge; but it is the simple tendency of the original will, which so exhibits itself to knowledge when knowledge appears. As now here the will brings about the regular figure without mathematics, so also without physiology does it bring about the form which is organised and furnished with organs evidently adapted to special ends. The regular form in space only exists for the perception, the perceptive form of which is space; so the design of the organism only exists for the knowing reason, the reflection of which is bound to the conceptions of end and means. If direct insight into the working of nature was possible for us, we would necessarily recognise that the wonder excited by teleology referred to above is analogous to that which that savage referred to by Kant in his explanation of the ludicrous felt when he saw the froth irresistibly foaming out of a bottle of beer which had just been opened, and expressed his wonder not that it should come out, but that any one had ever been able to get it in; for we also assume that the teleology of natural productions has been put in the same as it comes out for us. Therefore our astonishment at design may likewise be compared to that which the first productions of the art of printing excited in those who considered them under the supposition that they were works of the pen, and therefore had to resort to the assumption of the assistance of a devil in order to explain them. For, let it be said again, it is our intellect which by means of its own forms, space, time, and causality, apprehends as object the act of will, in itself metaphysical and indivisible, which exhibits itself in the phenomenon of an animal,—it is our intellect which first produces the multiplicity and diversity of the parts, and is then struck with amazement at their perfect agreement and conspiring together, which proceeds from the original unity; whereby then, in a certain sense, it marvels at its own work.
If we give ourselves up to the contemplation of the indescribably and infinitely ingenious construction of any animal, even if it were only the commonest insect, lose ourselves in admiration of it, and it now occurs to us that nature recklessly exposes even this exceedingly ingenious and highly complicated organism daily and by thousands to destruction by accident, animal rapacity, and human wantonness, this wild prodigality fills us with amazement; but our amazement is based upon an ambiguity of the conceptions, for we have in our minds the human work of art which is accomplished by the help of the intellect and by overcoming a foreign and resisting material, and therefore certainly costs much trouble. Nature’s works, on the contrary, however ingenious they may be, cost her absolutely no trouble; for here the will to work is already the work itself, since, as has already been said, the organism is merely the visibility of the will which is here present, brought about in the brain.
In consequence of the nature of organised beings which has been set forth, teleology, as the assumption of the adaptation of every part to its end, is a perfectly safe guide in considering the whole of organised nature; on the other hand, in a metaphysical regard, for the explanation of nature beyond the possibility of experience, it must only be regarded as valid in a secondary and subsidiary manner for the confirmation of principles of explanation which are otherwise established: for here it belongs to the problems which have to be given account of. Accordingly, if in some animal a part is found of which we do not see any use, we must never venture the conjecture that nature has produced it aimlessly, perhaps trifling, or out of mere caprice. Certainly it is possible to conceive something of this kind under the Anaxagorean assumption that the disposition of nature has been brought about by means of an ordering understanding, which, as such, obeys a foreign will; but not under the assumption that the true inner being (_i.e._, outside of our idea) of every organism is simply and solely _its own will_; for then the existence of every part is conditioned by the circumstance that in some way it serves the will which here lies at its foundation, expresses and realises some tendency of it, and consequently in some way contributes to the maintenance of this organism. For apart from _the will which manifests itself in it_, and the conditions of the external world under which this has voluntarily undertaken to live, for the conflict with which its whole form and disposition is already adapted, nothing can have influenced it and determined its form and parts, thus no arbitrary power, no caprice. On this account everything in it must be designed; and therefore final causes (_causæ finales_) are the clue to the understanding of organised nature, as efficient causes (_causæ efficientes_) are the clue to the understanding of unorganised nature. It depends upon this, that if in anatomy or zoology, we cannot find the end or aim of an existing part, our understanding receives a shock similar to that which it receives in physics from an effect whose cause remains concealed; and as we assume the latter as necessary, so also we assume the former, and therefore go on searching for it, however long we may already have done so in vain. This is, for example, the case with the spleen, as to the use of which men never cease inventing hypotheses, till some day one shall have proved itself correct. So is it also with the large spiral‐ formed teeth of the babyroussa, the horn‐shaped excrescences of certain caterpillars, and more of the like. Negative cases are also judged by us according to the same rule; for example, that in a class which, as a whole, is so uniform as that of lizards, so important a part as the bladder is present in many species, while it is wanting in others; similarly that dolphins and certain cetacea related to them are entirely without olfactory nerves, while the rest of the cetacea and even fishes have them: there must be a reason which determines this.
Individual real exceptions to this universal law of design in organised nature have indeed been discovered, and with great surprise; but in these cases that _exceptio firmat regulam_ applies, since they can be accounted for upon other grounds. Such, for example, is the fact that the tadpoles of the pipa toad have tails and gills, although, unlike all other tadpoles, they do not swim, but await their metamorphosis on the back of the mother; that the male kangaroo has the marsupial bones which in the female carry the pouch; that male mammals have breasts; that the _Mus typhlus_, a rat, has eyes, although very small ones, without any opening for them in the outer skin, which thus covers them, clothed with hair; and that the moles of the Apennines, and also two fishes—_Murena cœcilia_ and _Gastrobrauchus cœcus_—are in the same case; of like kind is the _Proteus anguinus_. These rare and surprising exceptions to the rule of nature, which is otherwise so rigid, these contradictions with itself into which it falls, we must explain from the inner connection which the different kinds of phenomena have with each other, by virtue of the unity of that which manifests itself in them, and in consequence of which nature must hint at some thing in one, simply because another of the same type actually has it. Accordingly the male animal has a rudimentary form of an organ which is actually present in the female. As now here the difference of the _sex_ cannot abolish the type of the _species_, so also the type of a whole order—for example, of the batrachia—asserts itself even where in one particular species (pipa) one of its determinations is superfluous.
Still less can nature allow a determination (eyes) which belongs to the type of a whole division (Vertebrata) to vanish entirely without a trace, even if it is wanting in some particular species (_Mus typhlus_) as superfluous; but here also it must at least indicate in a rudimentary manner what it carries out in all the others.
Even from this point of view it is to some extent possible to see upon what depends that _homology_ in the skeleton primarily of mammals, and in a wider sense of all vertebrates, which has been so fully explained, especially by Richard Owen in his “_Ostéologie comparée_,” and on account of which, for example, all mammals have seven cervical vertebræ, every bone of the human hand and arm finds its analogue in the fin of the whale, the skull of the bird in the egg has exactly as many bones as that of the human fœtus, &c. All this points to a principle which is independent of teleology, but which is yet the foundation upon which teleology builds, or the already given material for its works, and just that which Geoffroy St.
Hilaire has explained as the “anatomical element.” It is the _unité de plan_, the fundamental type of the higher animal world, as it were the arbitrarily chosen key upon which nature here plays.
Aristotle has already correctly defined the difference between the efficient cause (_causa efficiens_) and the final cause (_causa finalis_) in these words: “Δυο τροποι της αιτιας, το οὑ ἑνεκα και το εξ αναγκης, και δει λεγοντας τυγχανειν μαλιστα μεν αμφοιν.” (_Duo sunt causæ modi: alter cujus gratia, et alter e necessitate; ac potissimum utrumque eruere oportet._) _De part. anim._, i. 1. The efficient cause is that _whereby_ something is, the final cause that _on account of which_ it is; the phenomenon to be explained has, in time, the former _behind_ it, and the latter _before_ it. Only in the case of the voluntary actions of animal beings do the two directly unite, for here the final cause, the end, appears as the motive; a motive, however, is always the true and proper _cause_ of the action, is wholly and solely its _efficient_ cause, the change preceding it which calls it forth, by virtue of which it necessarily appears, and without which it could not happen; as I have shown in my prize essay upon freedom. For whatever of a physiological nature one might wish to insert between the act of will and the corporeal movement, the _will_ always remains here confessedly that which moves, and what moves _it_ is the _motive_ coming from without, thus the _causa finalis_; which consequently appears here as _causa efficiens_. Besides, we know from what has gone before that the bodily movement is one with the act of will, for it is merely its phenomenal appearance in cerebral perception. This union of the _causa finalis_ with the efficient cause in the one phenomenon _intimately_ known to us, which accordingly remains throughout our typical phenomenon, is certainly to be firmly retained; for it leads precisely to the conclusion that at least in organised nature, the knowledge of which has throughout final causes for its clue, a _will_ is the forming power. In fact, we cannot otherwise distinctly think a final cause except as an end in view, _i.e._, a motive. Indeed, if we carefully consider the final causes in nature in order to express their transcendent nature, we must not shrink from a contradiction, and boldly say: the final cause is a motive which acts upon a being, by which it is not known. For certainly the termite nests are the motive which has produced the toothless muzzle of the ant‐bear, and also its long extensile, glutinous tongue: the hard egg‐shell which holds the chicken imprisoned is certainly the motive for the horny point with which its beak is provided in order to break through that shell, after which it throws it off as of no further use. And in the same way the laws of the reflection and refraction of light are the motive for the wonderfully ingenious and complex optical instrument, the human eye, which has the transparency of its cornea, the different density of its three humours, the form of its lens, the blackness of its choroid, the sensitiveness of its retina, the contracting power of its pupil, and its muscular system, accurately calculated according to those laws. But those motives acted before they were apprehended; it is not otherwise, however contradictory it may sound.
For here is the transition of the physical into the metaphysical. But the latter we have already recognised in the _will_; therefore we must see that the will which extends an elephant’s trunk towards an object is the same will which has also called it forth and formed it, anticipating objects.
It is in conformity with this that in the investigation of _organised_ nature we are entirely referred to _final causes_, everywhere seek for these and explain everything from them. The _efficient causes_, on the contrary, here assume only a quite subordinate position as the mere tools of the final causes, and, just as in the case of the voluntary movement of the limbs, which is confessedly effected by external motives, they are rather assumed than pointed out. In explaining the physiological _functions_ we certainly look about for the efficient causes, though for the most part in vain; but in explaining the origin of the parts we again look for them no more, but are satisfied with the final causes alone. At the most we have here some such general principle as that the larger the part is to be the stronger must be the artery that conducts blood to it; but of the actually efficient causes which bring about, for example, the eye, the ear, the brain, we know absolutely nothing. Indeed, even in explaining the mere functions the final cause is far more important and more to the point than the efficient; therefore, if the former alone is known we are instructed and satisfied with regard to the principal matter, while, on the other hand, the efficient cause alone helps us little. For example, if we really knew the _efficient cause_ of the circulation of the blood, as we do not, but still seek it, this would help us little unless we knew the final cause, that the blood must go into the lungs for the purpose of oxidation, and again flow back for the purpose of nourishing; but by the knowledge of this, even without the knowledge of the efficient cause, we have gained much light. Moreover, I am of opinion, as was said above, that the circulation of the blood has no properly efficient cause, but that the will is here as immediately active as in muscular movement where motives determine it by means of nerve conduction, so that here also the movement is called forth directly by the final cause; thus by the need of oxidation in the lungs, which here to a certain extent acts as a motive upon the blood, yet so that the mediation of knowledge is in this case wanting, because everything takes place in the interior of the organism.
The so‐called metamorphosis of plants, a thought lightly thrown out by Kaspar Wolf, which, under this hyperbolic title, Goethe pompously and with solemn delivery expounds as his own production, belongs to the class of explanations of organic nature from the efficient cause; although ultimately he only says that nature does not in the case of every production begin from the beginning and create out of nothing, but as it were, writing on in the same style, adds on to what already exists, makes use of the earlier forms, developed, and raised to higher power, to carry its work further: just as it has done in the ascending series of animals entirely in accordance with the law: _Natura non facit saltus, et quod commodissimum in omnibus suis operationibus sequitur_ (_Arist. de incessu animalium, c. 2 et 8_). Indeed, to explain the blossom by pointing out in all its parts the form of the leaf seems to me almost the same as explaining the structure of a house by showing that all its parts, storeys, balconies, and garrets, are only composed of bricks and mere repetitions of the original unity of the brick. And not much better, though much more problematical, seems to me the explanation of the skull from vertebræ, although even here also it is a matter of course that the covering or case of the brain will not be absolutely different and entirely disparate from that of the spinal cord, of which it is the