that he had been the first to discover the solar spots, and that he had observed the satellites of Jupiter simultaneously with Galileo. For the leisure necessary for these researches he was indebted to the Earl of Northumberland, who, besides maintaining many other learned men, had settled on him a pension of £300 a year. Concerning this great mathematician Bacon makes a note in his Commentarius Solutus; but it is merely to the effect that he is "inclined to experiments." We cannot be surprised if hereafter we find Bacon-in his keen realization of the evils arising from the isolation of the labourers in the field of science-laying great, and perhaps too great, stress on the advantages to be expected from systematic division of labour and co-operation.

§ 46 THE SCHEME OF THE MAGNA INSTAURATIO" We have briefly considered the obstacles that Bacon saw before him in his path to scientific discovery — prejudice, suspicion, contempt, isolation, want of facts, want of means. But, of all the enemies of the New Philosophy, Aristotle and the Aristotelian spirit appear to have been regarded by him as the most dangerous; and perhaps a few words on the antagonism between the ancient and the modern philosopher may be no unfit preparation for understanding the objects of the latter. We cannot well understand what Bacon tried to effect, and how he tried, unless we first know what Aristotle failed to effect, and why he failed: and we may be led by Bacon's virulent invective against his great predecessor to judge the inveigher somewhat harshly unless we have a clear notion of the immense mischief which Aristotelianism had done, and was doing, to all science and all progressive thought. The mere completeness and literary symmetry of some of Aristotle's physical theories commended them to bookish, non-observant students, interested in natural science rather because of its bearing on theology than for its own sake; and their adoption. barred the way for progress. One or two instances may suffice. Aristotle's theory of astronomy was based on the belief that the heavens and all the heavenly bodies must be incorruptible, free from change and from irregularity: consequently

the motions of all the orbs must be in the perfect figure, the circle, and all the orbits must be concentric. Moreover the incorruptibility of the stars demanded that they should be made, not of the perishable four elements, but of an imperishable fifth essence or "quintessence."

These propositions he proved by appeal, not to observation nor to experiment, but to what is good and bad, to what is natural and unnatural. Thus, concerning the motion of the heavenly bodies, he argued that their motion "must go on constantly, and therefore must be either continuous, or successive. Now what is continuous is more properly said to take place constantly than what is successive. Also the continuous is better; but we always suppose that which is better to take place in nature, if possible." Again as to the fifth element, or quintessence, he argued after this fashion: We have proved that the heavenly bodies move in circles and for ever; but it is the nature of earth and water to move down, and of air and fire to move up: therefore the heavenly bodies either do not belong to the four elements, or else move in a motion contrary to their nature. But unnatural motions decay speedily. Therefore to the heavenly bodies (having been proved to move for ever) the circular motion must be natural. Therefore they do not belong to the four elements. Therefore they are composed of a fifth element or quintessence.” For similar reasons Aristotle gives his verdict against the possibility of a vacuum in nature: "In a void there could be no difference of up and down; for as in nothing there are no differences, so there are none in a privation or negation: but a void is merely a privation or negation of matter: therefore in a void bodies could not move up and down, which it is their nature to do. Therefore a void is against nature and impossible." 1

Such theories and such arguments commend themselves at once to children and it is not surprising that for many ages during the infancy of European civilisation, this symmetrical Aristotelianism took captive the imaginations of many minds, even after Ptolemy and Copernicus had published their astronomical hypotheses. It was against such a yoke as this that Bacon protested when he declared that "Aristotle's temerity and false reasoning had begotten for men a fantastic heaven, 1 Whewell, History of Inductive Sciences, i. pp. 43, 45, 54.

composed of a fifth essence, free from change; "1 and Aristotle is always in Bacon's mind when he declaims against the easy assent of the multitude to authority, and against the willingness of most men to receive, without discussion, symmetrical and agreeable, but fictitious, theories-no better than mere stageplays-which we shall presently find our philosopher branding with the name of the Idols of the Theatre.

It is a popular belief that Aristotle was led into the errors of his physical philosophy because he did not know Induction, which, it is thought, was first invented by Francis Bacon. This, however, is an error. Induction is nothing more than the introduction or induction of a number of particular instances to prove a general statement; and, consciously or unconsciously, every child is constantly in some sense practising Induction. All that we can say as to Aristotle's Induction is, that it was so different from Bacon's proposed Induction in certainty and completeness as almost to be different in kind. An important part of Bacon's Induction was the system of "exclusions;" that is to say, a method of gradually excluding such supposed causes of any phenomenon as do not invariably co-exist with the phenomenon. This, and other methods of increasing the efficiency of Induction were neglected by Aristotle. His Induction was for the most part what Bacon describes as "puerile" and " enumerative," without due selection or variation of circumstances (as though a child were to infer that all men are white because all the men whom he has met are white); and although Aristotle did occasionally experimentalize in physiological researches, his Induction was not systematically accompanied by experiment. Moreover, the disadvantages and limitations under which he worked, necessarily made his observations inadequate and insufficient; and in setting before himself scientific problems he sometimes hastily adopted (as if they were scientific terms) popular words implying popular notions, which were really vague, unscientific, and misleading. To say, for example, that a feather floats in the air because it is light, and that a stone falls in the air because it is heavy, and to infer that light things have a nature or appetite for rising, and heavy things have a nature or appetite for falling-this is not only untrue but an

1 Spedding, Works, v. 525.

untruth that is all the more dangerous because it is, as it were, democratic and suited to the minds of the multitude. It enthrones popular expressions, giving them supremacy over facts. In this particular error-which, strengthened by Aristotle's authority, blocked up for centuries the path towards the scientific explanation-Bacon himself appears to have shared; but the multitude of similar mistakes arising from the quasi-philosophic adoption of such terms as "hot," " cold," " moist," " dry," nature," "appetite," and the like, appears to have induced the modern philosopher to single out for reprobation this mischievous reaction on the mind resulting from popular words and notions, as being one of the special obstacles in the way of attaining the Truth; and—as this error sprang from the intercourse and common traffic of thoughts, represented by popular and inadequate words-he called it the Idol of the Market-place.

The reader of Bacon's works must not accept as exactly and literally true all his attacks on Aristotle. Against the exaggerated depreciation of Francis Bacon, Roger Bacon's words should be placed in the other scale: "Aristotle arranged all the departments of philosophy according to the possibilities of his time." 1

But the

When we compare his results with his means the work of the great Stagirite may be regarded as almost superhuman. True, he sometimes fell into the error of too hastily adopting some neat and consistent physical theory that conformed itself to his favourite metaphysical distinctions; but occasionally Bacon makes the teacher bear the blame that should fall on the scholars. It was not Aristotle, as Bacon declared,2 but Aristotle's followers, who asserted that one measure of earth is transmutable into ten of water; and one of water into ten of air. very fact that the Aristotelians could base such a dogma upon a mere misinterpretation of part of a single sentence of their master, attests most eloquently the servitude in which this Ottoman," as Bacon calls him, enchained posterity for ages. Under this Sultan the Schoolmen served as Mamelukes. By arguing, as Aristotle had done, from assumptions of what is best, or most wonderful, or most natural, and by a judicious use of the mystical meanings of numbers, it was possible to deduce,

1 Professor Fowler's Novum Organum, p. 73.

2 Spedding, Works, ii. 235.

by mere reasoning, most ample and satisfying accounts and explanations of all things in earth and heaven-especially in the latter. It was in the strength of Aristotle and the Aristotelian logic that Duns Scotus (1307), disputing before the University of Paris, demolished "two hundred objections" to the doctrine of the Immaculate Conception and resolved the knottiest syllogisms of his adversaries as Samson did the bonds of Delilah; and the same philosophy could be trusted to settle for mankind, by simple logic, the precise number of angels that could stand on the point of a pin. The syllogistic and metaphysical method admirably suited those who wished to systematize a vast system of ecclesiastical and theological doctrine, apart from all experience of human nature. Thus a universal science, obtained by reasoning alone, and intimately connected with the scholastic theology, was established with the authority of a religious creed; and theology came to be considered the only philosophy. It is said, though possibly it may be in hyperbole, that in some part of Germany the Ethics of Aristotle were read in the churches on Sunday, in the place of the Gospel : but there is no hyperbole in the saying of Francis Bacon that "the Schoolmen, having made Divinity into an art, have almost incorporated the contentious philosophy of Aristotle into the body of Christian religion."1

These considerations may enable us, while doing full justice to the great Greek philosopher, to understand, and in large measure to sympathise with, the burning indignation with which Bacon assails him. For "Aristotle," let us substitute "the Aristotelians," and every word of Bacon's invective will be true: their philosophy was barren; their induction was an imposture; and if they ever summoned Experience, it was, in the words of Bacon's bitter accusation, not to consult her as an adviser but to drag her at their chariot-wheels as a captive.2 Yet, for Bacon's own sake, we must regret the excess of his contempt and scorn for Aristotelianism. It placed a real and serious obstacle in the way of his own scientific work. Seeing so clearly where Aristotle had gone wrong, he was too apt to think that, by simply avoiding the mistakes of his predecessor,

1 Filum Labyrinthi, Works, iii. 499.

2 See the Redargutio Philosophiarum, p. 369, below.