From the Greeks to Darwin: An outline of the development of the evolution idea

Front matter

ety SS

Beet

phe eS

II. Among The Greeks

Never has the influence of Nature upon thought been more evident than in the philosophy and natural history of the Greeks. Whatever they may have drawn from the vague, abstract notions of development and transformation of Asiatic philosophers, they certainly recast into comparatively modern Evolutionism. No landlocked people could have put forth the rich suggestions of natural law which came from the long line of natural philosophers from Thales to Aristotle.

Their earliest known philosophy was a philosophy \ of Nature, of the origin and causes of the Universe. / As Zeller observes, they aimed directly at a theory before considering the severe conditions required for the attainment of scientific knowledge. How, then, can we explain the nearness of their easy guesses at the secrets of Nature to the results of modern labor? Only through this influence of the ‘ wzlzeu,’ of their physical surrounding upon their thought. ) It is in the environment of the sea we find the inspiration of Greek biological prophecy. Along the shores and in the waters of the blue A%gean, teeming with what we now know to be the earliest and simplest forms of animals and plants, they founded their hypotheses as to the origin and succession of life. Lucretius the Roman was Greek in spirit, but dwelling inland he substituted a terrestrial theory. Even the early Greek natural philosophy sprang more or less from observation, and therefore had some concrete value. It was not wholly imaginative.

The spirit of the Greeks was vigorous and hopeful. Not pausing to test their theories by research, they did not suffer the disappointments and delays which come from our own efforts to wrest truths from Nature. Combined with great freedom and wide range of ideas, independence of thought, and tendencies to rapid generalization, they had genuine gifts of scientific deduction, which enabled them to reach truth, as it were, by inspiration. As a case in point, Aristotle advanced a true theory of the nature of embryonic development by a very easy process, when contrasted with the slow steps which led to the establishment of the same theory of Epigenesis in the eighteenth century.

Their development from a childish to a mature philosophy was a slow one, and their thought upon Nature passed through four phases. First, the prehistoric mythological phase, which left its imprints in guesses as to the strange origin of monstrous forms of life, by the first natural philosophers who

SPIRIT OF THE GREEKS. 31 endeavoured to replace mythological by natural phenomena.

These pioneers contributed the spirit of the second phase, seen in the naturalism of the pre- Socratic period, suggesting Evolution, but neither conceiving of Evolution by slow stages of development nor seeking to explain Adaptation or Design in their systems of natural causation. They could not, in fact, speculate upon Design, as Zeller very acutely observes in reply to Lange, until the idea of Design as the result of a controlling Intelligence had arisen, and this idea was first developed by Anaxagoras, the last of the Physicists. He was followed by Socrates, who enlarged the theistic principle, which in the natural philosophy of Plato: and in the natural history of Aristotle, inspired.

the third or teleological phase.of thought. Then came the fourth phase, which was a naturalistic reaction to the novel and widely opposed mechanical or materialistic conceptions of the Universe developed by the Epicureans. |

—

Tur GREEK Pertops. (After Zeller.) GENERAL CONCEPTION OF NATURE.

Mythological. The Prehistoric ‘Traditions. I. Zhe Three Earliest Schools.

The Ionians. Thales (624-548), Anaximander (611-547), Anaximenes (588-524), Diogenes (440- ).

Naturalistic, The Pythagoreans. (580-430.) The Eleatics. Xenophanes (576- 480), Parmenides (544-_ ).

II. Physicists.

Heraclitus (535-475), Empedocles

DIVISIONS OF THE SCHOOLS.

FIRST PERIOD,

Earlier Materialistic, (495-435), Democritus (450- ), Anaxagoras, (500-428).

SECOND PERIOD. Socrates (470-399), Plato (427- S47) ie Teleological. Aristotle (384-322).

The Peripatetics, or post-Aristotelian school, including Theophrastus, Preaxagoras, Herophilus, Erasistratus.

TuirD Pertop. A. I. Zhe Stoics.

II. The Epicureans. Epicurus (341- 2470 B.C.).

Ill. Zhe Sceptics.

B. 1. Lelecticism. Galen (131-201 A.D.).

Later Materialistic.

In Zeller’s volumes on Greek Philosophy, and in his special discussion of Evolution among the Greeks, Die Griechischen Vorgiinger Darwin's, we find a full examination of the speculations of these ancient philosophers. Lange and Haeckel

THALES AND ANAXIMANDER. 33 tend to read into these speculations opinions which Zeller, with his more critical and exact analysis, throws into their actual relative value.

> Tuer Iontians AND ELEATICS.

THALES and ANAXIMANDER, the earliest Ionians, were students of Astronomy and of the origin of the Universe. So far as we know, they were the first who endeavoured to substitute a natural explanation of things for the old myths. Thales was also the first of the long line of natural philosophers who looked upon the great expanse of mother ocean and declared water to be the matter from which all things arose, and out of which they exist. This idea of the aquatic or marine origin of life, which is now a very widely accepted theory, is therefore an extremely ancient one. As has been said, it could only have arisen in a country surrounded by warm marine currents prodigal with shore and deep sea life.

ANAXIMANDER (611-547), the Milesian, is termed by Haeckel the prophet of Kant and Laplace in Cosmogony, and of Lamarck and Darwin in Biology! His theories were still largely imbued with mythology, and the more closely we examine them, the less they seem to resemble modern ideas. If we reduce this superlative prophetic mantle, we still find Anaximander imbued with a wealth of suggestion, and a literal prophet of some of the eighteenth century, rather than of the nineteenth century, speculations upon Evolution. He _ conceived of the earth as first existing in a fluid state. From its gradual drying up all living creatures were produced, degzuning with men. These aquatic men first appeared in the form of fishes in the water, and they emerged from this element only after they had progressed so far as to be able to further develop and sustain themselves upon land. This is rather analogous to the bursting of a chrysalis, than to progressive development from a simpler to a more advanced structure by a change of organs, yet a germ of the Evolution idea is found here.

We find that Anaximander advanced some reasons for this view. He pointed to man’s long helplessness after birth as one of the proofs that he cannot be in his original condition. His hypothetical ancestors of man were supposed to be first encased in horny capsules, floating and feeding in water; as soon as these ‘ fish-men’ were in a condition to emerge, they came on land, the capsule burst, and they took their human form. Anaxt mander, naturally, is not staggered by the differences of internal organization necessary for aquatic or terrestrial life, nor are we to translate the word petaB.ovv as ‘adaptation’ to new conditions of life, but simply as implying that the original fish-men persisted through their metamorphoses long enough to reproduce true men on land. There is, how-

ANAXIMANDER. 35 ever, the dim notion here of survival or persistence throughout decidedly trying circumstances, which was greatly developed later by Empedocles. In the fragments of Anaximander’s teachings we find he does not speculate upon the origin of other land animals, or intimate that he has any ‘notion of the

_ development of higher from lower organisms, except in the case of man. As to the origin of life in the beginning, he was the first teacher of the doctrine of Abiogenesis, believing that eels and other aquatic forms are directly produced from lifeless matter.

Grotesque as these ideas of Anaximander are, they indicatesa marked advance over the autochthonous myths of earlier times, according to which man grew, like a plant, directly out of the earth; for we find here an attempt to explain. human origin, upon the basis of natural analogies. Unfortunately, so little knowledge of Anaximander’s work is left us, that we can only obtain these vague glimpses of his opinions. _ANAXIMENES, his pupil (588-524), found in air the cause of all things. A\ir, taking the form of the soul, imparts life, motion,

‘and thought to animals. He introduced the idea | of primordial terrestrial slime, a mixture of earth and water, from which, under the influence of the sun’s heat, plants, animals, and human beings were directly produced—in the abiogenetic fashion. Diocengs of Apollonia (440- __), a late adherent of the Ionian school, also derived both plants and animals from this primordial earth slime. This is the prototype of Oken’s Ur-Schlecm.

XENOPHANES (576-480) was the founder of the Eleatic school, and is believed to have been a pupil of Anaximander. He agreed with his master so far as to trace the origin of man back to the transition period between the fluid or water and solid or land stages of the development of the earth, but we do not know how far he elaborated his ideas. The ultimate origin of life he traced to spontaneous generation, believing that the sun in warming the earth produces both animals and plants. He is famous in the annals of science as being the first to recognize fossils as remains of animals formerly alive, and to see in them the proofs that the seas formerly covered the earth, and that water was the element from which the earth emerged. PARMEN- IDES, his pupil, developed his cosmogony, and also derived men from the primitive earth slime directly engendered by the sun’s heat.

Tue PuySsICISTs.

The Physicists, Heraclitus, Empedocles, Democritus, and Anaxagoras, were far bolder and more _ fruitful in their suggestions. Among them we find that the vague notions of metamorphosis and the notions of Abiogenesis derived from the lIonians were developed into surprising anticipations of the true Evolution idea.

EMPEDOCLES. 37

Heracuitus of Ephesus (535-475) gave the impetus to this advance. He was so profoundly impressed with the ceaseless revolutions in the Universe that he saw in movement the universal law. Everything was perpetually transposed into new shapes. It must not be supposed for a moment that Heraclitus had even a remote notion of the transformation process of life. He was rather a metaphysician than a natural philosopher; and his principal contribution to the Evolution idea was manifestly in his broad view of Nature, as involved in perpetual_changes, yet always constituting a uniform whole.

EmpepocLes of Agrigentum (495-435) took a great stride beyond his predecessors, and may justly be called the father of the Evolution idea. He was not only a poet and musician, but made the first observations in Embryology which are recorded. Among his first physical principles we find the four elements — fire, air, water, and earth, — played upon by two ultimate forces, a combining | force, or love, anda separating force, or hate. He. believed in Abiogenesis, or spontaneous generation, as the explanation of the origin of life, but that) Nature does not produce the lower and higher forms simultaneously or without an effort. Plant. life came first, and animal life developed only after a long series of trials. After the first formation of the earth, and before it was surrounded by the sun, plants arose, and from their budding forth came animals. But this origin he believed to be a very gradual process, for even now the living world presents a series of incomplete products. All organisms arose through the fortuitous play of the two great forces of Nature upon the four elements. Thus animals first appeared, not as complete individuals, but as parts of individuals, — heads without necks, arms without shoulders, eyes without their sockets. Asa result of the triumph of love over hate, these parts began to seek each other and unite, but purely fortuitously. Thus out of this confused play of bodies, all kinds of accidental and extraordinary beings arose,—animals with the heads of men, and men with the heads of animals, even with double chests and heads like those of the guests in the Feast of Aristophanes. But these unnatural products soon became extinct, because they were not capable of propagation. Here it would appear that Empedocles was mainly endeayouring to give a naturalistic theory for the origin of the Centaurs, Chimzras, and other creations of Greek mythology. Thus, at least, Lucretius interpreted Empedocles many centuries later, putting these conjectures into verse (Book V. 860): —

“ Hence, doubtless, Earth prodigious forms at first Gendered, of face and members most grotesque : Monsters half-man, half-woman, not from each Distant, yet neither total ; shapes unsound,

EMPEDOCLES. 39

To act all impotent, or flee from harm, Or nurture ' take, their loathsome days t’extend. These sprang at first and things alike uncouth > Yet vainly ; for abhorrent NATURE quick Checked their vile growths; .

Hence, doubtless, many a tribe has sunk supprest, Powerless its kind to gender.” For whate’er Feeds on the living ether, craft or speed, Or courage stern, from age to age preserves In ranks uninjured: .. . : Yet Centaurs lived not ; nor could shapes like these Live ever, from two different natures reared, Discordant limbs and powers by powers reversed.”

Empedocles imagined that after these unnatural products became extinct, other forms arose which were able to support themselves and multiply; but even these were not formed at once. First came shapeless masses built of earth and water, or earth slime, without limbs, organs of reproduction, or speech, thrown from fires beneath the earth. Later came the separation of the two sexes and the existing mode of reproduction. These trials of Nature were not a succession of organisms, improving as time went on, but a series of direct births from Nature, which were unfit to live, and hence eliminated, until, after ceaseless trials, Nature produced the fit and perpetual tribes.

Thus, in the ancient teachings of Empedocles, we find the germ of the theory of the Szrvzval

1-2 It is interesting to note the remote parallel with the modern notion of the ‘struggle for existence’ as, mainly, success in feeding and in leaving progeny.

of the Fittest, or of Natural Selection. And the absolute proof that Empedocles’ crude hypothesis embodied this world famous thought, is found in passages in Aristotle’s Physzcs, in which he refers to Empedocles as having first shown the possibility of the origin of the fittest forms of life through chance rather than through Design. With Empedocles himself, however, it was no more than the potential germ of suggestion, which, in the brilliant mind of Aristotle, was stated precisely in its modern form, as we shall see later in our study of Aristotle.

Lange attributes to Democritus a similar interpretation of Empedocles’ teaching, namely, the “attainment of adaptations through the infinitely repeated play of production and annihilation, in which finally that alone survives which bears the guarantee of persistence through its relatively fortuitous constitution.” But Zeller takes a more conservative and sounder view of the real meaning of this old philosopher of Agrigentum. He says this could not have been advanced by Empedocles as an explanation of Design in Nature, because this idea had not yet been formulated in the Greek mind.

Empedocles was an evolutionist only in so far as he taught the gradual substitution of the less by the more perfect forms of life. He had a dim adumbration of the truth. There is no glimmering of slow development through the successive modification of lower into higher forms. His

DEMOCRITUS. 4I beings, which were incapable of feeding, reproducing, or defending themselves, were all produced spontaneously, or directly from the earth. He thus simply modified the abiogenetic hypothesis, and, by happy conjecture, gave his theory a ‘semblance of modern Evolution, with four sparks of truth, — first, that the development of life was a gradual process; second, that plants were évolved before animals; third, that imperfect forms were gradually replaced (not succeeded) by perfect forms; fourth, | that the natural cause of the production of perfect | orms was the extinction of the imperfect. Democritus (450- B.c.), the founder of the Atomistic philosophy, and precursor of materialism, studied and compared the principal organs of man and the lower animals. Cuvier has called him the first comparative anatomist. He did not, as Zeller points out, further the Evolution idea, because his teaching was not constructive in the way of advancing explanations of natural phenomena; it was simply destructive as regards Teleology. He perceived Design and admired the adaptations of Nature, but left their origin unexplained. As Zeller observes, Democritus had a gift for observing the purposeful direction and the functions of bodily organs, and Was in every way inclined, one would think, to explain these adaptations upon the principles of his mechanical philosophy, for he stood far from a teleological conception of Nature, yet he advanced no explanations. He denied that the Universe was

—_

AZa AMONG THE GREEKS.

created or ordered by reason. He adopted the older views as to the origin of animals and plants directly from the terrestrial slime. His main indirect contribution to the sub-structure of Evolution was his perception of the principle of the adaptation of single structures and organs to certain purposes, —an important step in advance, for Empedocles’ notion of adaptation extended only to organisms as a whole.

ANAXAGORAS (500-428 B.c.) took a further step. According to Plato and Aristotle, this philosopher was the first to attribute adaptations in Nature to Intelligent Design, and was thus the founder of Teleology. He also was the first to trace the origin of animals and plants to pre-existing germs in the air and ether. That the idea of Design was only developed in his mind to a very limited extent is shown in his history of the Universe. “All things existed, in some form, from the beginning. There were the germs, seeds, or miniatures of plants, animals, and minerals intermingled in the mass of matter. These germs had to be separated from the mass and arranged under the direction of Mind or Reason. The original chaos was heated; it divided into cold mist and warm ether. Water, earth, and minerals were formed from the former. The germs of plants were floating in the air; then they were carried down by the rains, and produced vegetation. The germs of animals, including those of man, were in the ether; they were fructified by the warm and moist terrestrial slime. In regard to Anaxagoras’ conception of adaptations as due to intelligent design in Nature, Zeller says: —

“The question whether the purposefulness of the tendencies of Nature (Natureinrichtung) could be explained without a purposeful working natural force — this question could not be raised until men had observed adaptation in Nature and had begun to attribute it to Intelligent Design. No one, according to Aristotle and Plato, had taken this step before Anaxagoras. But even he applied this newly discovered principle in exceptional cases, — not to the origin of life, surely, for he derived plants and animals from the air and ether. He did not, therefore, further the explanation of the problem of design in Nature, which Empedocles is mistakenly supposed to have raised.”

ARISTOTLE.

Give me no peeping scientist, if I Shall judge God's grandly-ordered world aright; But give, to plant my Cosmic survey high, The wisest of wise Greeks, the Stagirite. — JOHN STUART BLACKIE,

With Aristotle (384-322) we enter a new world. _ He towered above his predecessors, and by the force of his own genius created Natural History. | In his own words, lately quoted by Romanes, we learn that the centuries preceding him yielded him nothing but vague speculation : —

“T found no basis prepared ; no models to copy. . . . Mine is the first step, and therefore a small one, though worked out with much thought and hard labor. It must be looked at as a first step and judged with indulgence. You, my readers, or hearers of my lectures, if you think I have done as much as can fairly be required for an initiatory start, as compared with more advanced departments of theory, will acknowledge what I have achieved and pardon what I have left for others to accomplish.”

In the Physzcs and in the Matural History of Animals, are contained Aristotle’s views of Nature and his remarkable observations upon the plant and animal kingdoms. He was thoroughly versed in old Greek philosophy, and begins many of his treatises with a history of opinion, after the modern German fashion. He frequently quotes and discusses the opinions of Empedocles, Parmenides, Democritus, Heraclitus, Anaxagoras, and others. He undoubtedly inherited his taste for science from the line of physicians upon his father’s side, perhaps from the Asclepiads, who are said to have practised dissection. He was attracted to natural history by his boyhood life upon the seashore, and the main parts of his ideas upon Evolution were evidently drawn from his own observations upon the gradations between marine plants and the lower and higher forms of marine animals. He was the first to conceive of a genetic series, and his conception of a single chain of evolution from the polyps to man was never fully replaced until the beginning of this century. It appeared over and over again in different guises. In all his philosophy of Nature, Aristotle was guided partly by his preconceived opinions derived from Plato and Socrates, and partly by convictions derived from his own observations upon the wonderful order and perfection of the Universe. His ‘perfecting principle’ in ' Nature is only one of a score of his legacies to later speculation upon Evolution causation. Many of our later writers are Aristotelians without apparently being conscious of it.

Let us first look at Aristotle’s equipment as a naturalist. He enters a plea for the study and dissection of lower types: “ Hence we ought not with puerile fastidiousness to neglect the contemplation of more ignoble animals; for in all animals there is something to admire because in all there is the natural and the beautiful.” He distinguished five hundred species of mammals, birds, and fishes, besides exhibiting an extensive knowledge of polyps, sponges, cuttlefish, and other marine forms of life. His four essays upon the parts, locomotion, generation, and vital principle of animals, show that he fully understood Adaptation in its modern sense; he recognized the analogies if not the homologies between different organs like the limbs; he distinguished between the homogeneous tissues made up of like parts and the heterogeneous organs made up of unlike parts; he perceived the underlying principle of physiological division of labour in the different organs of the body; he perceived the unity of plan or type in certain classes of animals, and considered rudimentary organs as_ tokens a whereby Nature sustains this unity ; he rightly con- - ceived of life as the function of the organism, not as a’ separate principle; he anticipated Harvey’s doctrine of Epigenesis in embryonic development ; he fully perceived the forces “of hereditary transmission, of the prepotency of one parent or stock, and of Atavism_or Reversion; he also perceived the ‘compensation of growth’ principle as shown in a passage of his upon the origin of horns: “ Having now explained the purpose of horns, it remains to see the necessity of matter, by which Nature gave horns to animals; we see that Nature taking away matter from the front teeth (alluding to the ruminants) has added it to the horns.” He saw the fundamental difference_between animals and plants, and distinguished the organic or living world from the inorganic or lifeless world.

In his treatise upon the Generation of Animals (I. Sec. 35) we find him discussing the Heredity theories of Hippocrates and Heraclitus, which were similar to those of Democritus, and to the later Pangenesis of Darwin. He says: —

“Children resemble their parents not only in congenital characters, but in those acquired later in life. For cases are known where parents have been marked by scars, and children have shown traces of these scars at the same points; a case is also reported from Chalcedon in which a father had been branded with a letter, and the same letter somewhat blurred and not sharply defined appeared upon the arm of his child.”

Aristotle, however, does not accept the Pangenesis hypothesis of Heredity, nor does he suggest the inheritance of normal functional modifications. In his Hzstory of Animals he again refers to the inheritance of mutilations, remarking that such inheritance, although observed, is decidedly rare.’

We can pass leniently by errors which are strewn among such grand contributions to Biology and to the very foundation-stones of the Evolution idea. Aristotle showed practical ignorance of human anatomy and physiology; he failed to establish ,a natural classification; he also fostered the abiogenetic myth, that not only. smaller but larger animals, such as frogs, snakes, and eels, are produced spontaneously from the mud. Some of these and many other of his mistaken teachings were not wholly outlived until the present century; yet we may not allow them to detract from our general admiration of his great genius. His failures in descriptive science were chiefly in statements where he departed from his own principle of verification, and’relied upon the scientific hearsay of his day.

Aristotle’s method has been fully discussed in Lewes’ very interesting work, Arzstotle; a Chapter in the Firstory of Science. While Plato had, relied upon intuitions as the main ground of true knowledge, Aristotle relied upon experiment and) induction. ‘“ We must not,” he said, “accept a general principle from logic only, but must prove its application to each fact; for it is in facts that we must seek general principles, and these must always accord with facts. Experience furnishes the partic-

ular facts from which induction is the pathway to general laws” (History of Animals, |. 6). He held that errors do not arise because the senses are false media, but because we put false interpretations upon their testimony.

Aristotle’s theories as to the origin and succession of life went far beyond what he could have reached by the legitimate application of his professed method of procedure. Having now briefly considered the materials of his knowledge, let us carefully examine how he put his facts together into an Evolution system which had the teachings of Plato and Socrates for its primary philosophical basis.

Aristotle believed in a complete gradation in Nature, a progressive development corresponding with the progressive life of the soul. Nature, he _ says, proceeds constantly by the aid of gradual transitions from the most imperfect to the most perfect, while the numerous analogies which we find in the various parts of the animal scale show

_ that all is governed by the same laws, —in other words, Nature is_a_unit as to its causation, The lowest stage is the inorganic, and this passes into the organic by direct. metamorphosis, matter being transformed into life. Plants are animate as compared with minerals, and inanimate as compared with animals; they have powers of nourishment and reproduction, but no feeling or sensibility.

\ Then come the plant-animals, or Zodphytes; these are the marine creatures, such as sponges and seaanemones, which leave the observer most in doubt, for they grow upon rocks and die if detached. (Polyps Aristotle wrongly thought were plants, while sponges he rightly considered animals.) The

») third step taken by Nature is the development of , animals with sensibility, — hence desire for food —————— .

and other needs of life, and hence locomotion to fulfil these desires. Here was a more complex and energetic form of the original life. Man is the

Le highest point of one long and continuous ascent; ~ other animals have the faculty of thought; man - alone generalizes and forms abstractions; he is physically superior in his erect position, in his purest and largest blood supply, largest brain, and highest temperature.

How was this progression effected ?

Here we come to the second feature in Aristotle’s theory, which is more or less metaphysical,—it is the idea of the development of the potentiality of perfection into actuality, the creation - of form in matter. “Nature does nothing without ’/ an aim.” “She is always striving after the most beautiful that is possible.’ Aristotle perceived a most marvellous adaptation in the arrangement of the world, and felt compelled to assume Intelligent

Design as the primary cause of things, by the per-, fection and regularity which he observed in Nature. Nothing, he held, which occurs regularly can be the result of accident. This perfection is

E the outcome of an all-pervading movement, which we should, in nineteenth-century language, speak of as an ‘internal perfecting tendency.’ In Aristotle’s conception of ‘movement, as outlined in his Physzcs, we find something very analogous to our modern biological conception of transformation in development, for he analyzes ‘movement’ as every change, as every realization of what is possible, consisting in: (a) Swdstantzal movement, origin and decay, as we should now say, development and degeneration; (46) Quantitative movement, addition and subtraction, or, in modern terms, the gain and loss of parts; (c) Quattative movement, or the transition of one material into another, in metamorphosis and change of function; (@) Local movement, or change of place, in the transposition of parts.

Thus Aristotle thought out the four essential features of Evolution as a process; but we have found no evidence that he actually applied this conception to the development of organisms or of organs, as we do now in the light of our modern knowledge of the actual stages of Evolution. This enables us to understand Aristotle’s view of Nature as the principle of motion and rest comprised in his four Causes. Here again he is more or less metaphysical. The first is the ‘physical Material _- Cause,’ or matter itself; the second is the ‘ physical Formal cause,’ or the forces of the ‘ perfecting prin- . ciple’; the third is the ‘abstract Final cause,’ the fitness, adaptation, or purpose, the good of each and all; the fourth, presiding over all, is the ‘ Efficient cause, the Prime Mover, or God. Aristotle attributed all the imperfections of Nature to the struggle “en between the material and formal causes,—to the resistance of matter to form. There is room for difference of opinion as to whether he considered the Efficient cause, or God, as constantly present and working in Nature, or as having established a | preordained harmony. Romanes points out that