History of Materialism and Criticism of Its Present Importance Vol III

By Frederick Albert Lange

Originally published in 1825, this book contains volume three of the 'History of Materialism and Critique of Its Present Importance', and will prove to be a fascinating read for anyone with an interest in philosophy. Many of these earliest books, particularly those dating back to the 1900s and before, are now extremely scarce and increasingly expensive. Obscure Press are republishing these classic works in affordable, high quality, modern editions, using the original text and artwork.

• Language: English
• Publisher: Read Books Ltd.
• Release date: Jan 11, 2013
• ISBN: 9781447487555

Book preview

SECOND SECTION

Continued.

THE NATURAL SCIENCES.

CHAPTER III.

THE SCIENTIFIC COSMOGONY.

ONE of the most important questions in ancient Materialism was the question of the natural cosmogony. The much-ridiculed doctrine of the endless parallel motion of the atoms through infinite space, of the gradual entwinings and combinations of the atoms into solid and fluid, living and lifeless bodies, for all its singularity, had still a great work to accomplish. And beyond doubt these ideas have had a mighty influence upon modern times, though the connexion of our natural cosmogony with that of Epikuros is not so clear as the history of Atomism. It is rather the very point which subjects the ancient ideas to the first decisive modification, from which that idea of the origin of the universe was developed, which, despite its hypothetical character, even yet has the utmost importance. Let us hear Helmholtz on this point.

It was Kant who, feeling great interest in the physical description of the earth and the planetary system, had undertaken the laborious study of the works of Newton; and, as an evidence of the depth to which he had penetrated into the fundamental ideas of Kewton, seized the masterly idea that the same attractive force of all ponderable matter which now supports the motion of the planets must also aforetime have been able to form the planetary system from matter loosely scattered in space. Afterwards, and independently of Kant, Laplace, the great author of the ‘Mécanique Céleste,’ laid hold of the same thought, and introduced it among astronomers.⁴²

The theory of gradual condensation possesses the advantage that it admits a calculation, which through the discovery of the mechanical equivalent of heat has reached a high degree of theoretical perfection. It has been calculated that in the transition from an infinitely slight density to that of the present heavenly bodies as much heat must be produced from the mechanical force of attraction of the particles of matter as if the whole mass of the planetary system were expressed 3500 times in pure coal and this mass were then burned. It has been inferred that the greatest part of this heat must have lost itself in space before the present form of our planetary system could arise. It has been found that of that enormous store of mechanical force of the original attraction only about the 454th part is maintained as mechanical force in the motions of the heavenly bodies. It has been calculated that a shock which should suddenly stay our earth in its course would produce as much heat as the combustion of fourteen earths of pure coal, and that in this heat the mass of the earth would be completely fused, and at least the greatest part of it would evaporate.

Helmholtz observes that in these assumptions nothing is hypothetical but the presupposition that the masses of our system were in the beginning distributed in space as vapour. This is so far right, that from such a distribution, in co-operation with gravitation, the total sum of heat and mechanical motion may be approximately reckoned. But in order to produce our solar system as it actually is, we need further certain presuppositions as to the mode of distribution of the nebular masses in space. The rotation of the whole mass, once given, must of necessity become ever greater with the increasing contraction and condensation; its original existence may be deduced in many ways, but also belongs to the more special assumptions in which considerable play is still left to hypothesis. It is most simply explained by not making the nebular masses concentrate immediately and equably into a single great ball, but by making several such masses collect around their own centres of gravity and then fall together with a non-central impact. We will here, in passing, with reference to Ueberweg’s theory, to be mentioned later, interject that the whole process can be built also upon the collision of solid bodies, which, in consequence of the collision, first dissolve into a mass of vapour, and then, in the course of immeasurable time, are again organised into a new system.

The condensation hypothesis has gained an important support of late through spectrum analysis, which shows us that we find the same materials of which our earth consists in the whole solar system, and partly also in the stellar world. To the same method of inquiry we are indebted for the view that the nebulæ which appear scattered through the heavens by no means all consist, as might have been supposed earlier, of distant clusters of stars, but that a considerable number of them are really nebular masses, which may therefore present to us a picture of the earlier condition of our solar system.

In view of these confirmations, it is, on the other hand, of slight importance that recent geology has given up the revolutionary theory, and, so far as is at all possible, explains the formation of the surface of our planet from the same forces which we now see everywhere at work. The stability theory, which is supported on this geological tendency, can at most claim importance in a relative sense. We can regard the condition of the earth’s crust and the progress of the changes taking place in it as comparatively stable, as opposed to the theory of catastrophes, with which is frequently enough combined the shrinking from large figures referred to in the previous chapter. If, on the contrary, we assume sufficiently long periods, then a change, a becoming and perishing, is not only probable in itself, but it may be demonstrated on the strongest scientific grounds.

We may therefore well ask how it comes that we do not willingly deal with long periods of time; that, on the contrary, the idea of absolute stability lies comparatively so close to us; that in particular it has so little that is strange to our feelings? We descry the reason of this curious phenomenon only in the dulling habituation to the notion of eternity. This notion is familar to us from childhood, and, as a rule, we do not examine it carefully. Such, indeed, is the constitution of our mind, which is so closely connected with sensibility, that it seems necessary to lessen, as it were, absolute eternity in our conception, and to make it relative, in order in some degree to realise its meaning; much as we try to make the tangent of 90° in some degree picturable by making it become—i.e., by making before the eye of fancy a very great and ever greater tangent—although for the absolute there can no longer be any becoming. Thus the popular images of the theologians deal with eternity, which heap one period of time upon another in thought, and then make the very utmost that the imagination can reach, as it were, ‘a second of eternity.’ Although the notion of an absolute eternity includes so much, that all that the soaring imagination can possibly think compared with it is no more than the most trivial space of time, yet this notion is so familiar to us that the man who speaks of an eternal existence of the earth and of mankind seems comparatively modest beside the man who would merely multiply, say, the period of transition from the diluvial man to the man of to-day a millionfold, in order to go back to the origin of man from the simplest organic cell. Here sensibility is everywhere opposed to logic. What we can only in some degree picture to ourselves easily appears to us exaggerated and improbable, while we play with the most enormous conceptions when we have once brought them into the shape of an entirely abstract notion. Six thousand years on the one hand, eternity on the other—to this we are accustomed. What lies between them seems first remarkable, then bold, then magnificent, then fantastical; and yet all such predicates belong only to the sphere of feeling—cold logic has nothing to do with them.

It was formerly supposed, on a calculation of Laplace, that the period of the earth’s revolution, from the days of Hipparchos to the present, had not altered by the three-hundredth part of a second; and Czolbe has employed this calculation to support his stability theory. But it is quite clear that nothing more could follow from such a fact than that the retarding of the speed of revolution, which must be assumed as necessary from the physical theory, never goes more quickly than about 1 second in 600,000 years. But let us suppose that it reached a single second only in 100,000,000 years; still, after a few billions of years, the relations of day and night upon the earth must have been so totally changed that all the existing life of the surface must disappear, and the entire cessation of the axial revolution could not be far distant. We have, however, a thoroughgoing physical principle of this retardation in the effect of ebb and flood tides. Here all the conclusive keenness of mathematical conclusions finds its application. Only on the supposition of an absolute rigidity of the earth must the effects of the attraction which hinder the rotation completely cancel those which accelerate it. Since now there are some portions which may be delayed, the earth must of necessity receive an ellipsoid swelling, the delaying of which produces on the surface a friction, however slight it may be. The force of this inference cannot be in the least shaken by the fact that, according to recent observations, the phenomena of ebb and flood which we perceive on our coasts are not so much produced by a progressive swelling, but rather by one considerable elevation, which takes place when the middle of the largest expanses of sea is exactly opposite the moon or sun. Though the circular waves propagated from this elevation, as they proceed equally in every direction, have no retarding influence on the speed of rotation, yet the retarding influence of the flood must be equally present, though less perceptible. The process cannot possibly be the same as if the earth were to turn backwards, and in the position in which the flood-wave is formed were each time to remain motionless for some seconds. There must be a progressive flood-wave, unless all physics are deceptive. The actual flood-tide we may regard as composed of the effects of a standing and a progressive flood-wave. Even if the effect of the latter may apparently disappear in the infinitely complicated phenomena of ebb and flood, yet its retarding effect can never be lost. And however small a constantly acting cause may be, we have only to take sufficiently long periods of time and the result is inevitable. A portion of the living force of the planetary movement is absolutely destroyed by ebb and flood. We come thereby, says Helmholtz, to the unavoidable conclusion that every tide, although with infinite slowness, still with certainty, diminishes the store of mechanical force in the system; and as a consequence of this, the rotation of the planets in question round their axes must become more slow, and they must approach nearer to the sun or their satellites to them.

There is but one means of avoiding the conclusion that at last the revolution of the earth must cease, namely, if we can discover an opposite effect, which again accelerates the speed retarded by ebb and flood. Such an effect Mayer, the well-known discoverer of the equivalent of heat, formerly believed he had found, by supposing that the cooling of the earth is not yet finished. The earth—and with this he connected an explanation of earthquakes—is still constantly contracting, and therefore lessening its circumference, and with this must necessarily be involved an acceleration of the axial revolution. Mayer saw, however, very well that even in this assumption there lies no guarantee of eternal stability, since the two opposing influences cannot possibly maintain constantly an even pace. He assumed, therefore, three periods: one in which the acceleration in consequence of the contraction prevails; a second in which acceleration and retardation balance each other; and a third in which the retardation by ebb and flood prevails. Mayer believed at first that we are in the middle period, that of equilibrium; but he has abandoned this view. It is ten years since the English astronomer Adams, in London, led by the discovery of the retarding influence of ebb and flood, proved that Laplace’s calculation as to the constant duration of the sidereal day is not absolutely exact, since the speed of the earth’s rotation is lessened, and the sidereal day, therefore, is already augmenting. This makes, indeed, in the course of thousands of years, only a small fraction of a second, for a whole thousand years namely only 1/100 second! So that we must marvel at the human sagacity which has succeeded in ascertaining such an infinitesimal quantity.⁴³

An equally indispensable condition of an eternally unchanging planetary motion, as the absolute rigidity of the heavenly bodies, is the absolute emptiness of the space in which they move, or at least the entire absence of resistance in the æther, with which we suppose space to be filled. It appears that this condition too is not fulfilled. Enke’s comet describes, as it were, before our eyes an ever closer ellipse about the sun, and the most obvious way of explaining this is to suppose a resisting medium. Here indeed there is not the compulsion of a necessary deduction; but we have an observation which compels us to assume, as at least probable, the existence of a resisting medium. But with the mere fact of a resistance, however slight, of the æther nothing more need be said."⁴⁴

Absolutely convincing, again, is the conclusion that the heat of the sun cannot last for ever. It is impossible to avoid this conclusion by denying the fiery condition of the sun and supposing a source of heat in an eternal friction between the body of the sun and its covering, or the tether, or anything of the kind. Notions of this kind have, in fact, for the most part, been rendered impossible by the recent keenly prosecuted studies of the sun More rational is the hypothesis of the conservation of the sun’s heat by the continual falling in of meteorites and smaller bodies; but even this theory leads to no stability. And this is still less so with the view of Helmholtz, which we may well regard as the truest, viz., that the main source of the conservation of the sun’s heat is to be sought in gravitation.⁴⁵ The sun contracts, lessens its circumference, and thus mechanical force is converted into heat. That this process must, however, ultimately cease is matter of course. No motion can be conceived by which heat is produced without the consumption of other forces. We may suppose, therefore, any theory we choose as to the sun’s heat: it will always come to this, that the source of this heat is finite, while its consumption is infinite. We must always come to the conclusion that in the course of infinite time the to us so interminable duration of the sun’s heat and light will not only fall off, but will completely disappear.

Finally, there seems to result also, as a simple consequence of the mechanical theory of heat, the destruction of all life in the whole universe. As regards the earth, this destruction of course is involved in that caused by the extinction of the sun. Mechanical force can always be converted into heat, but heat can only be converted into work when it flows from a warmer to a colder body. With the equalisation of temperature in any system whatever ends the possibility of further changes, and accordingly of any kind of life. The sum of possible changes, or the ‘Entropy,’ as Clausius calls it, has reached its maximum.⁴⁶ Whether, however, this conclusion, though it rests upon conclusive mathematical reasoning, can actually be applied to the universe in the strictest sense of the term, depends essentially upon the ideas which we form of its infinity; and here we again find ourselves in a transcendental sphere. There is nothing, that is to say, to prevent us from multiplying such frozen systems at pleasure, and supposing them to attract each other from infinite distances, and then producing afresh from their collision the play of cosmogony as it were upon a larger scale. Nothing prevents us from making such an assumption except the question whether we are entitled, merely because we cannot conceive any limit to creation, to suppose a material infinity of worlds as actually existing.

Materialism taught even in ancient days the origin and destruction of our universe, while by the doctrine of the infinity of worlds it secured that satisfaction of the mind which lies in the simple belief in the permanence of things. Amongst our modern Materialists Czolbe especially has not been content with this, and postulates an eternal persistence of terrestrial life from the standpoint of our spiritual needs. Feuerbach’s categorical imperative, ‘Content thyself with the given world!’ seems to Czolbe impracticable until at least the persistence of this ‘given world’ is secured against the destruction threatened by the conclusions of the mathematicians. But it is very doubtful whether, from the standpoint of our peace of mind, it seems better completely to carry out one’s system while its very foundation remains exposed to the must violent concussions, or once for all to acquiesce in a limit to knowledge and opinion beyond which all questions are left open. In fact, in view of the convincing proofs which we have adduced, it must be seen that Czolbe’s satisfaction-theory is built upon sand, and therefore, in the long-run, can no more attain its end than the popular dogmatism which, on the contrary, will not give up a beginning and an end of things—the Creation and the Day of Judgment. If we once rise above this standpoint—if we seek the peace of the soul in what is given, we shall easily learn to find it not in the eternal duration of material conditions, but in the eternity of natural laws, and in such a duration of existing things as removes the idea of their destruction to a proper distance from us. The architectonic inclination of the reason will content itself, if we reveal to it the charm of a view of things which has no sensible support, but which also needs none, because the absolute is wholly set aside. It will remember that this whole world of relations is conditioned by the nature of our knowing faculty. And even though we always come back to this, that our knowledge does not disclose to us things in themselves, but only their relation to our senses, yet this relation is always more perfect, the freer it is; nay, it is, in fact, the more intimately related to the justified imagination of the absolute, the more free it holds itself of arbitary admixtures.

Almost more even than the origin of the universe has the origin of organisms for a considerable time occupied the thoughtful mind This question is of importance for the history of Materialism, if only because it forms the transition to those anthropological questions about which the Materialistic controversy has been wont to turn. The Materialist demands an explicable world: it is enough for him if the phenomena can be so conceived that the compound proceeds from the simple, the great from the small, manifold motion from simple mechanics. The rest affords him no anxiety, or rather he overlooks the difficulties which only come to view when the explicable world has been so far established in theory that the law of causality has no further sacrifice to demand. Even in this sphere Materialism has drawn nourishment from things which must be recognised from any rational standpoint; yet, until quite recent times, the origin of organisms was a point of which the opponents of Materialism made emphatic use. In particular, it was believed that the origin of organisms necessarily led us to a transcendental creative act, while in the arrangement and preservation of the organic world fresh supports for teleology were supposed to be constantly found. In fact, a certain opposition to Materialistic views was frequently connected with the very terms ‘organic,’ ‘living,’ inasmuch as here was found, as it were, the embodied antithesis of a higher, spiritually working force, as opposed to the mechanism of dead nature.

In mediæval, and still more at the outset of modern times, especially so far as the influence of men like Paracelsus and Van Helmont extended, no such chasm was found between the organic and inorganic worlds as in the last centuries. It was a widespread notion that all nature was animated. If even Aristotle made frogs and snakes originate from mud, such ideas were only too natural under the dominion of alchemy. Those who descried spirits even in metals, and a process of fermentation in their combination, could hardly find any special difficulty in the origin of life. There was, indeed, in general a belief in the invariability of species—a dogma which comes direct from Noah’s ark—but it was, at the same time, not taken too literally, and especially the lower creatures were made to the fullest extent to develop from inorganic matter. Both articles of faith have lasted till to-day—the one more amongst professors, the other amongst peasants and carters. The former believe in the invariability of species, and search twenty years perhaps in the bite of snails for proof of their belief; the latter are continually finding confirmation in their experience that fleas originate from sawdust and other materials. Science has only succeeded here later than elsewhere in bringing articles of faith down to hypotheses, and in stemming the broad current of opinions by experiment and observation.

The very question which first confronts us is even yet the object of a bitter controversy—the question of spontaneous generation (generatio aequivoca). Carl Vogt has given us a humorous account of how in Paris the scientific battle between Pasteur and his allied opponents, Pouchet, Joly, and Musset, is carried on with the bitterness of theologians, and with a dramatic effect which reminds us of the magistral theses of the fifteenth century. On Pasteur’s side are the Academy and the Ultramontanes. To controvert the possibility of spontaneous generation is a mark of conservatism. The old authorities of science were unanimous that no organic being can ever be produced without egg or seed. Omne vivum ex ovo is a scientific article of faith. But why do the orthodox take this side? Perhaps only to establish a something inexplicable, to spite the reason and the senses by holding fast to a purely mystical creation. The older orthodoxy, in the lead of S. Augustine, took quite another standpoint—to some extent a half-way one. There was no disdain of the notion of making things as intelligible as possible. Augustine taught that from the beginning of the world there had existed two kinds of seeds of living things: visible ones, which the Creator had placed in animals and plants, that each might bring forth after its kind; and invisible ones, which are concealed in all elements, and become active only under certain conditions of combination and temperature. It is these invisible seeds, latent in the elements from the first, which produce plants and animals in great numbers, without any co-operation of existing organisms.

This standpoint would be quite favourable to orthodoxy; it might even, without much trouble, be so far modified that, in the present state of the sciences, it might be maintained just as well as either of the two conflicting dogmas. But as in the heat of a contest the champion is often half compelled, half involuntarily changes his position, so too it happens in the whole course of scientific controversies. The Materialism of the last century here plays its part. In endeavouring to explain life from the inanimate, the soul from matter, the supposed origin of insects from decaying matter was ranged together with the resuscitation of dead flies by salt, with the voluntary movements of beheaded birds and other instances, for the Materialistic view. Friends of teleology and natural theology, supporters of the dualism of mind and nature, adopted as their tactics to controvert utterly the origination of insects and infusoria without generation; and the conflict of ideas led, as so often in the history of science, to fruitful and ingenious experiments, in which the Materialists were behindhand. After the much-read and admired Bonnet, in his ‘Contemplations de la Nature,’ had refuted generatio aequivoca, it was counted as spiritualism to maintain the omne vivum ex ovo, and in this point orthodoxy harmonised literally with the results of exact research. Indeed, it seemed almost to our own times as though that principle would be the more inexpugnably established the more exactly and carefully investigation went to work.

Metaphysic went mad over the new discovery. It was concluded that in natural propagation all future generations must be already contained in the egg or spermatozoon; and Professor Meier of Halle exhibited this ‘preformation theory’ so naively and vividly, that it would be unfair to our readers not to give them a sample. Thus, says the Professor, Adam must have carried all men in his loins; for instance, the very spermatozoon from which Abraham was. And in this spermatozoon all the Jews lay as spermatozoa. When, then, Abraham begat Isaac, Isaac went out from his father’s body and took with him, as part of himself, the whole race of his descendants.⁴⁷ The remaining unused spermatozoa, which it was natural to regard as possessing some share of soul, gave rise, as we may understand, to much wilder fantasies, which do not concern us here.

In recent times it was Schwann in particular who partly demonstrated the true element of all organic formations in the cell, partly showed by a series of experiments that in the apparent origin of organisms by generatio aequivoca the presence of eggs or germ cells must always be presupposed. His methods of proof were generally regarded as excellent, but it was one of our own Materialists, Carl Vogt, who definitely expressed his doubts of their sufficiency, long before the old controversy burst again into such violent flame in France. We gather the tenour of his keen and thorough criticism from the Bilder aus dem Thierleben, 1852.

The infusoria originate from the combination of air, water, and organic matter. Schwann found means to destroy all organic germs in these constituents. If now they are isolated and yet infusoria originate, then generatio acquivoca is proved. Hay was boiled with water in a retort until not only all the fluid, but even the air in the neck of the retort, was heated to the boiling-point. It was known that in closed retorts no infusoria would originate. If now ordinary air was admitted to the retort, then infusoria always appeared despite the previous boiling; if, on the contrary, only air was admitted which had been passed through a red-hot tube, through sulphuric acid, or through caustic potash, no infusoria ever appeared. Now it is supposed that the composition of the air is not altered by the means employed. This is, however, only approximately true. The atmosphere contains not only oxygen and nitrogen. It contains a certain quantity of carbonic acid, of aqueous vapour, of ammonia, perhaps infinitesimal quantities of many other matters. These are by the means adopted more or less decomposed and absorbed, the carbonic acid by the potash, the ammonia by the sulphuric acid. The heating of the air must produce a partial influence upon the arrangement of its molecules . . . We have cases enough in chemistry where apparently very inconsiderable circumstances are needed to produce a combination or decomposition. . . . It is possible that just the precise quantity of ammonia, of carbonic acid, that a certain disposition or tension of the atmospheric molecules is necessary in order to set up and complete the process of the fresh formation of an organism. The conditions in which the two retorts are placed are therefore not perfectly alike, and therefore also the experiment does not appear quite conclusive. In fact, this argumentation shows the inadequacy of Schwann’s experiment, and the question may therefore be treated as an open one, especially as a series of weighty considerations is opposed to the assumption that all the germs of the countless infusoria which appear in these experiments circulate in the air in a condition capable of life. Ehrenberg supposed a division of the infusoria, which proceeding in geometrical ratio would in a few hours people the water; Vogt, on the contrary, has shown the improbability of this hypothesis.⁴⁸ Recently the practice has arisen of systematically collecting the dust particles winch may be floating in the air before the experiment: is begun. Pasteur throws his collection of supposed germs and eggs into the fluids intended to be experimented with, and believes that he thus sows infusoria and funguses; Pouchet previously examines the collection. He lets hundreds of cubic metres of air stream through water, and examines the water, he invents an instrument which blows the air against glass plates, to which the seminal dust lemams attached, he analyses dust which has been deposited, and he makes these experiments on the glaciers of Maladetta in the Pyrenees, as well as in the Catacombs of Thebes, on the continent as well as on the sea, on the Pyramids of Egypt as well as at the summit of Rouen Cathedral. Thus he brings together a mass of air-inventories, in which, indeed, everything conceivable figures, but only very seldom a germ-spore of a fungus plant, and much seldomer still the dead body of an infusorium.

For all this, the state of things remained that spontaneous generation had not been demonstrated despite the pains spent upon it. Schwann’s experiments were varied and modified in the most manifold ways, but as often as spontaneous generation seemed to be reached, more exact experiments showed that the possibility of a communication of germs was not excluded. The greatest impression was produced in the last few years by the experiments of Bastian and of Huizinga. The latter in particular were very seductive, since in a hermetically fused glass retort, after ten minutes’ boiling of the liquid, there appeared Bacteria, and only Bacteria; so that it seemed safe to assume spontaneous generation at least for these simplest of organisms. But in Pfluger’s laboratory the same liquid, fastened up in the same way, was kept boiling for hours, and even after it had cooled no Bacteria were produced. There remained, therefore, the possibility that there were germs in the liquid which were not destroyed by ten minutes’ boiling, though they could not resist a longer application of heat.⁴⁹

At the same time it must be admitted that continuous boiling might possibly destroy other and as yet unknown conditions of Bacterial existence So that the proof is by no means convincing that there were actually germs present in the liquid which were in the first case developed, and in the second destroyed. The result, therefore, of all these experiments remains, that spontaneous generation is not established, and just as little shown to be impossible.

A fresh possibility for the origin of organisms seemed to be opened by the discovery of Monera, those formless, and, so far as our means of examination reach, structureless lumps of protoplasm, which maintain, nourish, and propagate themselves without possessing any distinct organs. Haeckel, who regards spontaneous generation as an indispensable, if as yet unconfirmed hypothesis, promises himself much in this regard from a slime-creature living in the still depths of the sea of the following kind:—"Even among the Monera at present known there is a species which probably even now always comes into existence by spontaneous generation. This is the wonderful Bathybius Haeckelii, discovered and described by Huxley. This Moneron is found in the greatest depths of the sea, at a depth of between 12,000 and 24,000 feet, where it covers the ground partly as retiform threads and plaits of plasma, partly in the form of larger or smaller irregular lumps of the same material."⁵⁰

If we do not accept the hypothesis of spontaneous generation, he says further on, "then at this one point of the history of development we must have recourse to the miracle of a supernatural creation. The Creator must have created the first organism, or a few first organisms, from which all others are derived, and as such He must have created the simplest Monera or primitive Cytods, and given them the capability of developing further in a mechanical way. Haeckel rightly finds the latter idea just as unsatisfactory to a believing mind as to a scientific intellect. We may, however, go further, and assert that such an alternative is logically quite inadmissible. To scientific research the intelligibleness of this world must be an axiom; and if, therefore, we hold spontaneous generation to be improbable, the origin of organisms remains simply as a yet unsolved problem. Natural science has not the slightest occasion now or ever to suppose a supernatural" act of creation. To fall a victim to such explanations is accordingly always an abandonment of scientific ground, which in a scientific inquiry can never be mentioned as admissible, or even as matter for consideration. To those, however, who regard a creative act as a spiritual necessity, it must be left to consider whether they prefer to take refuge with it in that dark corner which the light of science has not yet reached, or whether they rather declare against all science, and, untouched by the rules of the understanding, believe what seems good to them; or whether, lastly, they know how to take up their stand on the ground of the ideal, and revere what science calls a natural event as an outcome of Divine power and wisdom. That only the last standpoint is suited to an advanced state of culture, while the first is indeed the commonest, but also in every way the weakest, we need here only indicate.

Finally, it by no means follows that to give up terrestrial spontaneous generation involves the giving up of any possibility of asserting a consistent causal connexion in nature.

Here we have first to consider a recently proposed hypothesis of the English physicist Thomson,⁵¹ which derives the origin of the organisms upon our earth from space, and makes use of meteorites to carry them. When a volcanic island springs up from the sea, and after a few years is found clothed with vegetation, we do not hesitate to assume that seed has been wafted to it through the air or floated to it on rafts. Is it not possible, and, if possible, is it not probable, that the beginning of vegetable life on the earth is to be similarly explained?

Thomson regards the meteorites as fragments of ruined worlds which were once covered with life. Such ruins may in a collision partly remain tolerably uninjured, though a great portion of them is melted. If, then, we suppose that there are at present, and. have been from time immemorial, many worlds of life beside our own, we must regard it as probable in the highest degree that there are countless seed-hearing meteoric stones moving about through space. If at the present instant no life existed upon this earth, one such stone falling upon it might, by what we blindly call natural causes, lead to its becoming covered with vegetation.

Zollner tries to show that this hypothesis is unscientific; first of all formally, because it only postpones the problem, and so makes it more complicated. We must then ask, Why was this ruined world covered with vegetation and our own not? But he would also call it materially unscientific to make meteorites the bearers of the seed, because the friction with our atmosphere must make them red-hot.

Helmholtz, who defends Thomson’s hypothesis against the reproach of being unscientific, reminds us that the large meteorites are heated only externally and remain cold internally, where such seeds might very well be sheltered in crevices. And even the seeds situated at the outside, upon entering the outer strata of the atmosphere, would be blown inwards before the heat could reach a destructive degree. Helmholtz, who had even before Thomson mentioned, in a scientific lecture, the same hypothesis as admissible, is ready to leave it to every one whether to regard it as so extremely improbable. But, he remarks, it seems to me a thoroughly correct scientific procedure, when all efforts to produce organisms from lifeless matter have failed, to ask whether life ever has originated, whether it is not as old as matter, and whether its germs my not have been carried about from one world to another, and have been developed wherever they found a favourablesoil.⁵²

It is, in fact, very easy to answer to Zollner’s formal objection, that we must suppose our earth to have been originally devoid of vegetation simply because it had to pass from a fiery-fluid condition into a condition capable of vegetation. If we suppose that the other world has gone through just the same process, only at an earlier period, it must of course have derived its life from a third world, and so on. This indeed is to push the question further back, but by no means makes it more complicated. In any case, that great shoal is avoided which the explanation of organisms finds in Kant’s hypothesis of condensation. We find ourselves in a process ad infinitum, and this kind of ‘postponement’ has at least the advantage that it brings the unsolved difficulty into good company. The origin of life thus becomes as explicable and as inexplicable as the origin of the world generally; it comes into the sphere of transcendental problems, and to transfer it into this sphere is by no means logically improper, as soon as natural science has good grounds within its sphere of knowledge to regard such a theory of transmission as relatively the most probable.

Zollner agrees with Haeckel that generatio aequivoca can only be denied on a priori grounds by doing violence to the law of cause. Instead, however, of admitting at the same time the possibility of a supernatural creative act, he regards the question, deductively considered, as decided, and even regards it as a lack of philosophical culture that the men of science still attach so much value to the inductive proof of generatio acquivoca. With formal correctness he observes, that by no perfection of experiment could we escape the germ-theory, since we could not prevent any one from maintaining that the primitive organic germs belonged in point of size to the order of æther-atoms, and forced their way with the latter through the intervals between the material molecules which form the boundaries of our apparatus. At the same time this remark can at most only be sometimes applied satirically to the certainty with which Pasteur and similar dogmatists hold that their experiments have definitely refuted generatio aequivoca. No one will seriously propose such an hypothesis, as long as we see that in certain cases a fluid sealed up for a very long period remains without any trace of life.

Inductive inquiry, therefore, is here by no means so indefensible, as long as it reaches various results by various methods and can compare these. Even