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IN 1627, the year after that in which Bacon died, his chaplain Dr. Rawley published the Sylva Sylvarum. The preface is Rawley's own, and was written in Bacon's lifetime; it gives some account of Bacon's views touching the kind of natural history required as the foundation of the instauration of the sciences, but contains little or nothing which is not found elsewhere. Although Rawley says that in the present work the materials for the building are collected, yet it cannot be doubted but that Bacon was fully conscious that, even taken in conjunction with the treatises De Ventis and De Vitâ et Morte, &c., the Sylva Sylvarum falls far-short of his own idea of a just and perfect Natural History. We should do him injustice if we were to suppose that he was satisfied with the collection of facts here published, of which much the greater part are taken from a few popular writers. We ought rather to regard it as a proof that Bacon's thoughts were busied, up to the close of life, with his plan for the reform of philosophy, and as the work of a man who, knowing that he could not accomplish his own designs, was yet resolved, in spite of worldly troubles and of increasing infirmities, to labour on in the good cause which he had so long had in hand. That it was Bacon's last work gives it a peculiar interest, though the habits of thought which in the seventeenth century made it a popular book have long since passed away. Curiosity about isolated or slightly connected facts seems gradually to decline, as scien

All men

tific notions become more generally diffused; the interest which we feel in any phenomenon is much impaired, when we know that however marvellous it may seem to us it can nevertheless be intelligibly explained. Men learn by degrees to leave off wondering, and to seek for causes, or trust for information to those who do. At present, popular books on science attempt for the most part to make abstract theories intelligible, or at least to give an account of what these theories are about. But in Bacon's time, and still more at an earlier period, men delighted in nothing more than in collections of remarkable facts; the more marvellous, so they did not become altogether incredible, the better. In those days men were much more nearly on a level in scientific matters than they are now; and the reader of Mizaldus or of John Baptist Porta was not mortified by the reflection that his wonder was only the result of his own ignorance. were, as it seemed, equally ignorant of the occult causes of phenomena, and if any explanation was offered it was such as all men could equally understand. For at best these explanations involved only loose and popular notions of force and motion, and for the most part they merely referred the phenomena to sympathy and antipathy, the influence of the stars, specific forms, and the like, of which principles the modus operandi was, by the consent of all men, held undiscoverable. To this class of writings the Sylva Sylvarum seems naturally to belong, and, in truth, a considerable part of it is copied from the most celebrated book of the kind, namely Porta's Natural Magic. It has doubtless a more scientific character than the average of similar works, but there are some to which in this and in other respects it is decidedly inferior. I refer particularly to Cardan's De Subtilitate, and to his De Rerum Varietate. Both of them supplied some of the facts mentioned in the Sylva Sylvarum.

I may be allowed to digress for a moment from the Sylva Sylvarum to a subject of considerable interest, namely the facility with which miraculous stories were received in the middle ages. We are apt to regard this as a proof of the prevalence of gross superstition; whereas in reality miracles were simply believed like other marvels. The habit of asking how effects are produced had then no existence, and consequently the à priori difficulty which hinders men from believing



in wonderful stories, except on commensurate evidence, was never felt. Every one believed, for instance, that bleeding might be stopped by touching the wounded man with a bloodstone, why might not the same effect be produced by the relic of a saint? And so in all similar cases.

The à priori conceivability of any assertion is one of the circumstances by which men are decided in believing or disbelieving it; but this operates differently according to the mental habits of different

The subject cannot here be pursued farther, though, from its connexion with the application of the theory of probabilities to questions of evidence, it is by no means unimportant.

The Sylva Sylvarum consists of one thousand paragraphs, and is divided into ten centuries. Each of these paragraphs contains a statement of one or more facts, accompanied generally by some remarks tending more or less to explain the causes of the observed phenomena. The facts themselves are derived from a variety of sources; some from Bacon's own observation, some perhaps from oral report, and the remainder from books. In many places they seem to have been noted down as the book from which they are taken was read; at least they occur in the same order as in the original work. The principal sources are Aristotle's Problems, his De mirabilibus auscultationibus (not genuine), and his Meteorologics ; Pliny's Natural History, Porta's Natural Magic, and Sandys's Travels. To these are to be added Cardan De Subtilitate, Scaliger Adversus Cardanum, and one or two others. The Natural Magic contributes more than any other book, and next to it, I think, Aristotle's Problems.

The route which Sandys, whose book was published in 1615, followed in his travels may almost be traced in Bacon's extracts. Thus, in (701) he is at Lemnos, from whence he proceeds in the next two paragraphs up the Dardanelles to Constantinople. In (704) and (705) we find some mention of what he saw there; a subject resumed in (738) and continued to (741). In (743) he has reached Egypt, where he is found again in (767) and the next paragraph. The succeeding sixteen paragraphs follow him, with some admixture of extraneous matter, through Syria and Palestine to Sicily and the neighbourhood of Naples.

From Cardan is taken the great mass of what is said in the tenth century touching sympathy and antipathy. One or two

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