"tions. The other class of phenomena are those that oc"cur in substances that are placed altogether beyond

our reach, the order and succession of which we are "generally unable to control, and as to which we can do "little more than collect and record the laws by which they appear to be governed. These substances are not the "object of experiment, but of observation; and the knowledge we may obtain, by carefully watching their varia"tions, is of a kind that does not directly increase the

power which we might otherwise have had over them. "It seems evident, however, that it is principally in the "former of these departments, or the strict experimental "philosophy, that those splendid improvements have been "made, which have erected so vast a trophy to the pro"spective genius of Bacon. The astronomy of sir Isaac "Newton is no exception to this general remark; all "that mere observation could do to determine the movements of the heavenly bodies, had been accomplished by the star-gazers who preceded him; and the law of 46 gravitation, which he afterwards applied to the planetary "system, was first calculated and ascertained by experiments performed upon substances which were intirely "at his disposal.

"It will scarcely be denied, either, that it is almost exclusively to this department of experiment that Lord "Bacon has directed the attention of his followers. His "fundamental maxim is, that knowledge is power; and

the great problem which he constantly aims at resolving, "is, in what manner the nature of any substance or quality may, by experiment, be so detected and ascertained, "as to enable us to manage it at our pleasure. The great

er part of the Novum Organum, accordingly, is taken

up

with rules and examples for contriving and conduc'ting experiments; and the chief advantage which he "seems to have expected from the progress of these inquiries, appears to be centered in the enlargement of "man's dominion over the material universe which he "inhabits. To the mere observer, therefore, his laws of "philosophizing, except where they are prohibitory laws, "have but little application; and to such an inquirer, the "rewards of his philosophy scarcely appear to have been promised. It is evident, indeed, that no direct utility "can result from the most accurate observations of oc"currences which we cannot control; and that, for the

66

uses to which such observations may afterwards be "turned, we are indebted, not so much to the obser"ver, as to the person who discovered the application. "It also appears to be pretty evident, that, in the art of "observation itself, no very great or fundamental im"provement can be expected. Vigilance and attention "are all that can ever be required in any observer; and though a talent for methodical arrangement may facili"tate to others the study of the facts that have been col"lected, it does not appear how our knowledge of these "facts can be increased, by any new method of descri"bing them. Facts that we are unable to modify or direct, in short, can only be the objects of observation; and "observation can only inform us that they exist, and that "their succession appears to be governed by certain gene"ral laws.

"In the proper experimental philosophy, every acquisition of knowledge is an increase of power; because "the knowledge is necessarily derived from some inten"tional disposition of materials, which we may always

แ

"command in the same manner. In the philosophy of "observation, it is merely a gratification of our curiosity. By experiment, too, we generally acquire a pretty cor"rect knowledge of the causes of the phenomena we pro"duce, as we ourselves distribute and arrange the cir"cumstances upon which they depend; while, in matters " of mere observation, the assignment of causes must always be, in a good degree, conjectural, inasmuch as we "have no means of separating the preceding phenomena, "or deciding otherwise than by analogy, to which of them "the succeeding event is to be attributed."

As the whole of this passage tends to depreciate the importance of a very large department of Physics, no less than of the science of Mind, the discussion to which it leads becomes interesting to Philosophers of every description; and, therefore, it is unnecessary for me to make any apology, either for the length of the quotation, or for that of the examination which I propose to bestow on it. It is sufficient for me to remind my readers, that, in the remarks which follow, I plead the cause not only of Locke and his followers, but of such star-gazers as TychoBrahe, Kepler, Galileo, and Copernicus.

That it is by means of experiments, judiciously conducted, that the greater part of the discoveries in modern physics have been made, I readily admit. Nay, I am satisfied, that it is by a skilful use of this great organ of investigation, much more than by any improvements in the art of observing the spontaneous appearances of the universe, that the physical inquiries of Bacon's followers are chiefly characterized, when contrasted with those of the ancient schools. The astronomical cycles handed down to us from the most remote antiquity; the immense

treasure of facts with respect to natural history, preserved in the works of Aristotle and of Pliny; and the singularly accurate histories of the phenomena of disease, which some of the Greek physicians are allowed to have bequeathed to posterity, abundantly justify the remark which was long ago made by a medical writer, that " if "the ancients were not accustomed to interrogate Nature, "they, at least, listened to her with an unremitted atten"tion."*

In farther illustration of the utility of experiment, it may be remarked, that in proportion as a particular science opens a field to address and invention, in thus extorting the secrets of Nature, the rate of its progress is subjected to human genius and industry. What is the great cause of the uncertainty in which medicine continues to be involved? Is it not, that, in addition to the difficulties which it has to struggle with, in common with the other branches of physical knowledge, it depends, more than any of the rest, upon accident for its improvement? The experimentum periculosum, and judicium difficile are complaints as old as the time of Hippocrates.

While, however, I make this concession in favour of experiment, as the most powerful organ we can employ in the study of Nature; and admit, in their fullest extent, the advantages peculiar to those sciences in which we can, at pleasure, avail ourselves of its aid; I must be allowed to add, that I am unable to perceive the slightest connection between the premises and the conclusion they have been employed to establish. The difference between experiment and observation, consists merely in the compara

* Van Doeveren.

tive rapidity with which they accomplish their discoveries; or rather in the comparative command we possess over them, as instruments for the investigation of truth. The discoveries of both, when they are actually effected, are so precisely of the same kind, that it may safely be affirmed, there is not a single proposition true of the one, which will not be found to hold equally with respect to the other. It ought to be remembered, too, that it is in hose branches of knowledge, where there is least room for experiment, and where the laws of nature are only to be detected by cautiously collecting and combining a multitude of casual observations, that the merits of the philosopher are the greatest, where he succeeds in his re

searches.

That the conclusions of the astronomical observer, with respect to the laws by which the phenomena of the heavens are regulated, contribute, in any degree, to extend the sphere of his power over the objects of his study, no star-gazer, so far as I know, has yet boasted. But have these conclusions had no effect in extending his power over that scene where he is himself destined to be the principal actor? Have they contributed nothing to the progress of chronology and of geography; or to the improvement of that art which, by guiding his course across the pathless ocean, has completed the empire of man over the globe? One thing, at least, is evident, that Newton's discovery of the law of Gravitation, notwithstanding the experiments which supplied him with some data essential to his results, has added nothing to the power of man, the utility of which does not resolve into the same general principle, with that of the observations of TychoBrahe, and of Kepler. The planetary system still remains