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had slowly attained by the labours of successive generations. If this were true, it would be, as we have intimated, nothing short of miraculous. It would be as if Eclipse not only distanced all competitors in the race, but was gifted with a faculty by which he could reach the goal without passing over the intermediate ground. For science is knowledge built on knowledge; it is not an affair of intuition. Neither is a happy guess, figuring perhaps amidst a crowd of vagrant fancies, to be dignified with the name of a scientific truth. There is no such thing as the anticipation of a discovery, unless the intermediate steps also have been anticipated, by which alone it becomes a discovery, or is distinguished from a random guess. Amidst such opposite estimates as these, such unqualified detraction on the one hand, such inordinate and impossible praise on the other, Mr. Lewes offers himself as our guide. He has given us an analysis of Aristotle's scientific writings quite ample enough for the purpose at which he aims. Had it been more complete, the patience of the reader would have broken down; had it been briefer than it is, we should have complained that materials enough had not been given for an independent judgment. He himself holds the balance with impartiality, or, at least, with the evident effort to be impartial. Between the careless detractor who echoes a contempt which had become conventional, and the lover of paradox, or the pedantic devotee of whatever is ancient and whatever is Greek, Mr. Lewes steers his middle course. He is, perhaps, more successful, more completely convincing, when he combats the exaggerated praise of certain admirers of Aristotle, than when he himself becomes eulogistic. Desirous of assuming the more agreeable attitude of bestowing praise, he, on two occasions, opens the chapter with a rather startling note of admiration, but the extracts which follow hardly support his own eulogium. He gradually relapses

into the calm and clear-sighted critic. On the whole, the work will confirm and render distinct the vague impressions which most of us have received of the science of Aristotle ; that it was all that could be expected from mortal man living at the period of Aristotle, but that, regarded from our present position, it can have no value except to those who are curious to trace the progress of the human mind.

And indeed it is from this point of view that Mr. Lewes invites us to the study of the scientific works of Aristotle. A mere history of past blunders is the dreariest thing imaginable. We are too anxious to learn something of real science, and there is too much on every side to be learnt, to allow us time for studying, merely for their own sake, the inevitable mistakes and errors of the past.

And remember that in science the past error is utterly extinct-dead beyond all possibility of revival. It is otherwise in philosophy. The old quarrels here are always capable of being rekindled. Often they are the same disputes which agitate the living generation; nay, it has happened that a speculation in philosophy, after having been given over to mere ridicule as a flagrant folly of the past, has been revived, and taught, with some modifications, as a profound truth. We should not wonder if the very age we live in took to the belief in the transmigration of souls. When souls inhabit the legs of tables, or creep under chairs and paw us about the knees, this old fancy of the East must surely seem a most respectable article of faith. There is no folly of this kind that may not be revived. But a scientific hypothesis, once fairly supplanted, is extinct for ever; its place can know it no more; there, where it stood, and where alone it could stand, another growth has occupied the soil. The transmigration of souls might be revived to-morrow; phlogiston is dead for ever. Philo sophical speculations are like the clouds of heaven, which may rise to

day and disperse to-morrow, just as they rose and dispersed a thousand yesterdays ago. Science is like the tree which grows from the seed, and from a seedling extends its branches into the air, but goes never back into the seed again.. To write a narrative, therefore, of the errors of the past, that had no other object than simply to record such errors, would be the most wearisome and useless of tasks. But, in fact, it is not in this barren spirit of narrative that Mr. Lewes, or any philosophical writer, would invite us to survey the mistakes and tentatives of the past. It is as part of the history of that, living human mind which is still with us, and is still ours, that this narrative of its past wanderings becomes valuable. Phlogiston and the like are dead, and let them be buried so far as they are individually concerned; but that human spirit from which science grew is with us still, and we would study this its faculty of growth, and trace the method of its progress. From this point of view a history of scientific errors becomes a history of the development of the human mind. We highly approve of Mr. Lewes's undertaking to write what he terms the embryalogy of science; nor need we suggest to a writer of his tact and discrimination that it would be useless to load his pages with a multitude of errors of the same kind. We have read histories of medicine where the philosophical lesson which might be learnt from past errors was quite lost sight of in the multitude of instances given of absurd hypotheses and miserable nostrums. The attention was fatigued by the mere enumeration of fantastic speculations, which were followed, alas ! by very real sufferings to the patient in the shape of cruel and dis gusting remedies. On the other hand, there is no more effective manner of expounding the latest tenets or discoveries of science than by a judicious account of the errors and mistakes which preceded them, and which often led the way to

them. And Mr. Lewes has shown in the present volume that he well understands the art of mingling together the modern truth of science and the ancient guess-work, so that by their contrast they may throw light upon each other. Of course, when we speak of the truth of modern science, we do not forget that many of our truths may be destined to figure as pardonable errors in the pages of some future historian of science.

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A brief account of the life of Aristotle naturally precedes the criticism upon his philosophy, or rather, we should here say, upon his science. This relates, in a short compass, all, we believe, that is known of Aristotle's personal history. As the few facts that bear the stamp of credibility are familiar to most readers, or at least lie open to every one in the pages of biographical dictionaries, we need not repeat them here. But in this our critical age the following list of the authorities on which all these accounts are founded will be acceptable. It will be seen how remote we are from any thing like contemporary evidence,

"

What, then, are the dates, or thereabouts? Aristotle was born B.C. 384. Diogenes Laertius, whose narrative is the fullest, the best, and the most generally followed, was born, at the earliest, and it is even supposed that he was as nearly six centuries later. e., A.D. 200; late as Constantine. The next on our list is Ammonius, (if the work be really his,) who comes eight centuries after his hero, in A.D. 460; and that these eight centuries have not been profitably employed in sifting tradition and bringing it nearer to accuracy, may be gathered from a single detail noticed by Buble, that Aristotle is made a pupil of Socrates, who died just fifteen years before the Stagirite was born. The nearest biographer in point of time is Dionysius of Harlicarnassus, (B.c. 50,) and this gives a gap of

three centuries; moreover, one meagre chius was born A.D. 500, nearly nine cenpage comprises all he has to say. Hesyturies too late; the date of Suidas is uncertain, but probably not earlier than the eleventh century of our era.

"These writers contradict each other on separate points. What means have we for deciding between them? They may have had contemporary documents as their authorities; but what guarantee have we for the accuracy of these documents? It is but just three hundred years since Shakespeare was born; throughout this period he has been prized and written about; compilers have done their worst upon this subject; yet what do we authentically know of his life? Above all, what value do we attach to the earliest biography, that of Rowe?"

What can a modern Englishman do but accept such of the facts as appear to him probable and coherent? That Aristotle was, in the language of our times, a gentleman of birth and fortune, who, simply from an ardent love of knowledge, devoted himself to philosopy; that, born at Stagira, a town of northern Greece, situated in what is now called the Gulf of Contezza, he migrated to Athens, the intellectual capital of Greece and of the world, where Plato was then teaching; that, after many years of laborious application, his reputation was such that it brought an invitation from Philip of Macedon to undertake the education of the young Alexander-are facts, we presume, that we may accept without distrust. There is one trait of character ascribed to Aristotle, which we hope also we may believe in: this great thinker, one of the most indefatigable and powerful of the class that has lived upon the earth, was a tender and warm-hearted man, capable of love and of ardent friendship.

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"His health," says Mr. Lewes in that general summary of personal details which make up for us the picture of a was, like that of most ardent brain-workers, delicate. He was short and slender in person; he had small eyes and an affected lisp. Somewhat given to sarcasm in conversation, he made, of course, many enemies. On hearing that some one had vituperated him in his absence, he humorously said, If he pleases, he may beat me too-in my absence. His heart was kind, as was manifest in certain acts, and is expressed in this saying, 'He who has many friends

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One of the last and most, conspicuous incidents of his life appears to corroborate this impression of his affectionate chapter. When, upon the death of Alexander, the Macedonian party in Athens belonged to this party, was exposed lost their power, and Aristotle, who to the malice of his enemies, the worst charge these could bring against him was, that he had paid divine honours to his wife and to his friend. He had burned the one and raised a statue to the other in a too sacred manner, or too sacred locality thus infringing on the rights and privileges of the gods. In liberal and enlightened Athens, if a man was to be destroyed, the surest way was to represent him as a profane person-a despiser of the gods; to accuse him, in fact, of irreligion, or heresy of some kind. An incautious or too ambitious testimony of affection was the impiety alleged against our philosopher. He retired, we are told, before the coming storm. Mindful of the death of Socrates, he refused to the Athenians a second opportunity of disgracing the republic.

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Mr. Lewes opens his criticism on the science of Aristotle with the following general account of his physics:—

"The physical writings of Aristotle still extant are the eight books of Physics,' the four books On the Heavens, the two books on Generation and Corruption,' with the Meteorology' and the Mechanical Problems.' The contents of these works very slightly correspond with their titles, according to modern concep tions. The sciences which we class under the heads of Physics and Astronomy are in no sense represented in them. There is no attempt to sketch the laws of Statics, Dynamics, Optics, Acoustics, Thermotics, or Electricity. There is nothing beyond metaphysical disquisitions sug gested by certain physical phenomena; wearisome disputes about motion, space,

infinity, and the like; verbal distinctions, loose analogies, unhesitating as sumptions, inexpressibly fatiguing and unfruitful. They have furnished matter for centuries of idle speculation, but few beams of steady light to aid the groping endeavours of science. We cannot say that in every point he is

altogether wrong -on some points he was assuredly right; but these are few, isolated, without bearing on the rest of his speculations, and without influence on research. I shall therefore analyse these works much more rapidly and briefly than the works on Biology."

We are thus inducted into some of those earlier doctrines, or me

thods of thinking upon physical topics, which belong not exclusively, indeed, to Aristotle, but to the age in which he lived. We are taught the principle of Contraries, once a theme of learned disquisition throughout Europe

"There are," says Aristotle, "three principles: Matter, Form, and Privation. In every phenomenon we can distinguish the substance and its form; but as the form can be only one of two contraries, and as only one of these two can exist at each moment, we are forced to admit the existence of a third principle, Privation, to account for the contrary which is absent. Thus a man must be either a musician or a non-musician; he cannot be both at the same time: and that which prevents his being one of these is the privation of the form."

Then we have a definition of nature as "the principle of Motion and Rest;" and of Movements it is added, that "those are called natural which are self-moved." Further on we are told that there are two great classes of movements1. The natural; and, 2. The violent or unnatural. Fire ascends and a stone descends by natural movement. A stone may be made to ascend, but this is owing to violence. Some external motor causes it to ascend; by its natural movement the stone would never rise, but always fall. For a similar reason, fire may be made to descend; but, left to its natural movement, it will only ascend,

We have in these few passages a fair specimen of that mode of

thought, or false method, which Aristotle and his contemporaries brought to the study of nature. Men of acute intellect, eager to give at once to the phenomena before an explanation of all things, applied them some abstraction or generalisation ready made in the language of daily use, They should have occu pied themselves, we are apt to say, with the collection of facts; they should have formed generalisations from this careful observation of facts, and then proceeded to reason on these ferences at each step by fresh apgeneralisations, verifying their inpeals to observation and experi

ment. Such is the true method of science. But we perceive very which the man of science permits clearly that the generalisations from himself to reason deductively (because originally formed from careful induction) were not then in existence, and could not have been then in existence. Were these men to be silent? If it is said they should have occupied themselves with ob servation and experiment, the answer is at hand: No men ever did, train of observation or experiment, or could, pursue to advantage a unless under the guidance of some There is hypothesis or conjecture. some guess of their own they seek to establish, or guess of others they seek to overthrow. Conjecture and experiment must at all times proceed together. These early sages were to blame, not so much for what they did, as what they left undone. They conjectured much and experi mented little: but it was something to conjecture; the rest of the world neither observed nor conjectured.

The false method of the Greek philosopher did not consist in any theoretical neglect of observation. He knew the value of a fact as well as his modern successor; but he lived at a time when those generalisations formed by careful observation had not yet been made. He himself might be helping to make them, but as yet they were not. What could he do but avail himself of such ideas or generalisations as an

uncritical experience had produced, and which, perhaps, were incorporated into the very language of daily use? Gravity, or the attraction of matter to matter, is a generalisation of modern science; it is formed from induction or observation, and we permit ourselves, therefore, to reason on it with confidence. It enters into our explanation of this or that still perplexing phenomenon. The principle of contraries was the result of no careful induction; it was snatched up in haste. Heat drives out cold, and cold heat. Was there not a principle here of universal application? So amongst motions of inanimate bodies were not some natural, just as certain motions in our own organism are felt to be natural? It was a rude analogy - an unauthorised generalisation.

The difference between the false method and the true is the inevitable result of position in the course of time, or process of development. The modern man of science reasons from generalisations which are the results of a hitherto universal experience; but, waiting the formation of these, the earlier sage reasoned on something which was the result of a scanty experience or a fanciful analogy. He had nothing better to

reason on.

What, let us ask ourselves, is the kind of observation on which science is founded, or with which science commences? It is not the mere use of our senses, or the mere perception of objects. Nor do we call by the name of Science that practical knowledge of the qualities of things so essential to life, as that fire burns, or food nourishes. Such knowledge as the senses directly give us lies, we need not say, at the basis of all science, but is not science itself. There are two kinds of observation on which science depends: 1st, When we detect similarities between things or events which at first sight appeared widely different, and thus establish an essential identity where only diversity had presented itself; and, 2d, When, amongst the

series of events perpetually occurring around us, we select those which are unalterably united in never-failing sequence, or relation of cause and effect, and classify them apart from those whose connection is not invariable. And now let us ask, what motive or passion it is that prompts to observation of this subtle kind? It is not our daily wants or appetites. These may greedily seize upon knowledge of a scientific kind, which they can make subservient to them; they do not originally lead to it. Science originates in that noble curiosity with which men, or at least some men, are endowed-the desire to understand all, to see all as with the eye of intellect; to harmonise what seems confused; to represent to themselves the whole in its completeness. And now one question more, Would you check this curiosity till all legitimate appliances were ready for its gratification; would you prevent it from asking questions and giving answers till it had been strictly demonstrated what kind of questions were to be asked, and how precisely the answer was to be obtained? Manifestly such restrictions, instead of leading to a more rapid progress in knowledge, would have rendered all effort and all development impossible; they would have killed at once the noble curiosity we are speaking of. Honour to those who, stimulated by this generous passion, persisted energetically to think, in the full confidence that finally the human intellect would triumph over all difficulties.

Proceeding in our analysis, we come upon a curious notion relative to motion in a vacuum :—

"Aristotle argues that in vacuo motion is impossible. In a void there can be no difference of place; and motion implies difference of place. He then after the original motor ceases to be in adds, that projectiles continue moving contact with them, either, as some say, by reaction, or by the motion of the moved air. Moreover,' he adds, 'no one can say why, in vacuo, a body once set in motion should ever stop;

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