doubt that we dream, as it is to assert that we have the same evidence for the existence of an external world, as for the existence of the sensations by which it is suggested to our minds.

We dare not venture farther into this subject; yet we cannot abandon it without observing, that the question is entirely a matter of philosophical and abstract speculation; and that by far the most reprehensible passages in Dr. Reid's writings, are those in which he has represented it as otherwise. When we consider, indeed, the exemplary candour, and temper, and modesty, with which this excellent man has conducted the whole of his speculations, we cannot help wondering that he should ever have forgotten himself so far as to descend to the vulgar raillery which he has addressed, instead of argument, to the abettors of the Berkleian hypothesis. The old joke, of the sceptical philosophers running their noses against posts, tumbling into kennels, and being sent to a madhouse, is repeated at least ten times in different parts of Dr. Reid's publications, and really seems to have been considered as an objection not less forcible than facetious. Yet Dr. Reid surely could not be ignorant, that those who have questioned the reality of a material universe, never affected to have perceptions, ideas, and sensations of a different nature from other people. The debate was merely about the origin of these sensations, and could not possibly affect the conduct or feelings of the individual. The sceptic, therefore, who has been taught by experience that certain perceptions are connected with unpleasant sensations, will avoid the occasions of them as carefully as those who look upon the objects of their perceptions as external realities. Notions and sensations he cannot deny to exist; and this limited faith will regulate his conduct exactly in the same manner as the more extensive creed of his antagonists. We are persuaded that Mr. Stewart would reject the aid of such an argument for the existence of an external world.

The unexpected length to which these observations have extended, deters us from prosecuting any farther our remarks on Dr. Reid's philosophy. The other points in which it appears to us that he has left his system vulnerable, are, his explanation of our idea of cause and effect, and his speculations on the question of liberty and necessity. In the former, we cannot help thinking that he has dogmatised, with a degree of confidence which is scarcely justified by the cogency of his arguments, and has endeavoured to draw ridicule on the reasoning of his antagonists, by illustrations that are utterly inapplicable. In the latter, he has made something more than a just use of the prejudices of men and the ambiguity of language, and has more than once been guilty, if we be not mistaken, of what, in a less respectable author, we should not have scrupled to call the most palpable sophistry. We are glad that our duty does not require us to enter into the discussion of this very perplexing controversy; though we may be permitted to remark, that it is somewhat extraordinary to find the dependence of human actions on motives so positively denied by those very philosophers with whom the doctrine of causation is of such high authority.

PHILOSOPHICAL ESSAYS. BY DUGALD STEWART.*

Mind, not the proper subject of Experiment, but of Observation.-Effects of the Cultivation of Modern Physics, and of the Philosophy of Mind contrasted.

In the second part of the Preliminary Dissertation, we will confess that we take a lively interest; as Mr. Stewart has there taken occasion to make a formal reply so some of our hasty speculations, and has done us the honour of embodying several of our transitory pages in this enduring volume. If we were at liberty to yield to the common weaknesses of authors, we should probably be tempted to defend ourselves in a long dissertation; but we know too well what is due to our readers and to the public, to think of engaging any considerable share of their attention with a controversy which may be considered in some measure as personal to ourselves; and therefore, however honourable we think it, to be thus singled out for equal combat by such an antagonist, we shall put what we have to say within a very narrow compass.

The observations to which Mr. Stewart has here condescended to reply occur in an early Number of our publication, † and were intended to show, that as mind was not the proper subject of experiment, but of observation, so there could be no very close analogy between the rules of metaphysical investigation, and the most approved methods of enquiry as to those physical substances which are subjected to our disposal and control;-that as all the facts with regard to mind must be derived from previous and universal consciousness, it was difficult to see how any arrangement of them could add to our substantial knowledge; and that there was, therefore, no reason either to expect discoveries in this branch of science, or to look to it for any real augmentation of our power. The argument upon this head was summed up in the following passage, which Mr. Stewart has not thought it necessary to quote in the Dissertation before us, though it was certainly intended to contain that ultimate view of the subject, by which we were most willing to abide, and most desirous to be tried.

“For these reasons, we cannot help thinking that the labours of the metaphysician, instead of being assimilated to those of the chemist or experimental philosopher, might, with less impropriety, be compared to those of the Grammarian, who arranges into technical order the words of a language which is spoken familiarly by all his readers; or of the Geographer, who exhibits to them a correct map of a district, with every part of which they were previously acquainted. We acquire a perfect knowledge of our own minds without study or exertion, just as we acquire a perfect knowledge of our native language or our native parish; yet we cannot, without much study and reflection, compose a grammar of the one, or a map of the other. To arrange in correct order all the particulars of our practical knowledge, and to set down, without omission and without distortion, every thing that we actually know upon a subject, requires a power of abstraction, recollection, and disposition, that falls to the lot of but few. In the science of mind, perhaps, more of those qualities are required than in any other; but it is not the less true of this than of all the rest, that the materials of the description must always be derived from a previous acquaintance with the subject,-that nothing can be set down technically that was not practically known,-and that no substantial addition is made to our knowledge by a scientific distribution of its particulars. After such a systematic arrangement has been introduced and a correct nomenclature applied, we may indeed conceive more clearly, and will certainly describe more justly, the nature and extent of our information; but our information itself is not really increased; and the consciousness by which we are

Vol. xvii. page 173. November, 1810.

See an able review of Stewart's Life of Reid, vol. iii. page 269, &c. That the reader may clearly understand the nature of the controversy between the Edinburgh Review and the distinguished author of the Philosophical Essays, he should peruse the whole of the second chapter of the Preliminary Dissertation to that work, page 26, &c., which was intended as a reply to the observations of the critic in his strictures upon Reid's Philosophy.

supplied with all the materials of our reflections, does not become more productive by this disposition of its contributions. "

With regard to perception and the other primary functions of mind, it was added, that this doctrine seemed to hold without any limitation; and as to the associating principle while it was admitted that the case was somewhat different, it was observed, that all men were in reality aware of its existence, and acted upon it in all practical cases, though they might never have made its laws a subject of reflection, nor ever stated its general phenomena in the form of an abstract proposition.

To all this Mr. Stewart proceeds to answer, by observing that the distinction between experiment and observation is really of no importance whatever, in reference to this argument; because experiments are merely phenomena that are observed; and the inferences and generalisations that are deduced from the observation of spontaneous phenomena, are just of the same sort with those that are inferred from experiment, and afford equally certain grounds of conclusion, provided they be sufficiently numerous and consistent. The justice of the last general proposition we do not mean to dispute; and assuredly if any thing inconsistent with it is to be found in our former speculations, it must have arisen from that haste and inadvertence which, we make no doubt, have often betrayed us into still greater errors. But it is very far from following from this, that there is not a very material difference between experiment and observation; or that the philosophy of mind is not necessarily restrained within very narrow limits, in consequence of that distinction. Substances which are in our power are the objects of experiment; those which are not in our power, of observation only. With regard to the former it is obvious, that, by well-contrived experiments, we may discover many things that could never be disclosed by any length of observation. With regard to the latter, an attentive observer may, indeed, see more in them than strikes the eye of a careless spectator; but he can see nothing that may not be seen by every body; and in cases where the appearances are very few, or very interesting, the chance is, that he does see nothing more, and that all that is left to philosophy is, to distinguish them into classes, and to fit them with appropriate appellations. Now, mind, we humbly conceive, considered as a subject of investigation, is the subject of observation only; and is known nearly as well by all men, as by those who have most diligently studied its phenomena. "We cannot decompose our sensations," we formerly observed, "in a crucible, nor divide our opinions with a prism." The metaphor was something violent; but the meaning obviously was, that we cannot subject those faculties to any analogous process, nor discover more of their nature than consciousness has taught all the beings who possess them. Is it a satisfactory answer, then, for Mr. Stewart to say, that we may analyse them by reflection and attention, and other instruments better suited than prisms or crucibles to the intellectual laboratory which furnishes their materials? Our reply is, that we cannot analyse them at all; and can never know more of them than has always been known to all to whom they had been imparted; and that for this plain reason, that the truth of every thing that is said with regard to the mind can be determined by an appeal to consciousness alone, and would not be even intelligible, if it informed men of any thing that they did not previously feel to be true.

With regard to the actual experiments to which Mr. Stewart alludes as having helped to explain the means by which the eye judges of distances

and magnitudes, these we must observe, are, according to our conception, very clearly experiments, not upon mind, but upon matter; and are only entitled to that name at all, in so far as they are carried on by means of the power we possess of disposing certain pieces of matter in certain masses and intervals. Strictly considered, they are optical experiments on the effects produced by distance on the appearance of bodies; and are nearly akin to experiments on the effects produced on their appearance by the interposition of media, of different refracting powers, whether in the shape of prisms, or in any other shape. At all events, they certainly are not investigations carried on solely by attending to the subjects of our consciousness, which is Mr. Stewart's own definition of the business of the philosophy of mind.

In answer to our remark, that "no metaphysician expects, by analysis, to discover a new power, or to excite a new sensation in the mind as the chemist discovers a new earth or a new metal," Mr. Stewart is pleased to observe

"That it is no more applicable to the anatomy of the mind, than to the anatomy of the body. After all the researches of physiologists on this last subject, both in the way of observation and of experiment, no discovery has yet been made of a new organ, either of power or of pleasure, or even of the means of adding a cubit to the human stature; but it does not therefore follow that these researches are useless. By enlarging his knowledge of his own internal structure, they increase the power of man in that way in which alone they profess to increase it. They furnish him with resources for remedying many of the accidents to which his health and his life are liable; for recovering, in some cases, those active powers which disease has destroyed or impaired; and, in others, by giving sight to the blind, and hearing to the deaf, for awakening powers of perception which were dormant before. Nor must we overlook what they have contributed, in conjunction with the arts of the optician and of the mechanist, to extend the sphere of those senses, and to prolong their duration." Prelim. Diss. p. xlvi. xlvii.

Now, ingenious and elegant as this parallel must be admitted to be, we cannot help regarding it as utterly fallacious, for this simple reason-that the business of anatomy is to lay open, with the knife, the secrets of that internal structure, which could never otherwise be apparent to the keenest eye; while the metaphysical enquirer can disclose nothing of which all his pupils are not previously aware. There is no opaque skin, in short, on the mind, to conceal its interior mechanism; nor does the metaphysician, when he appeals to the consciousness of all thinking beings for the truth of his classifications, perform any thing at all analogous to the dissector, when he removes those outward integuments, and reveals the wonders of the inward organisation of our frame. His statements do not receive their proof from the previous, though perhaps undigested knowledge of his hearers, but from the actual revelation which he makes to their senses; and his services would evidently be more akin to those of the metaphysician, if, instead of actually disclosing what was not previously known, or suspected to exist, he had only drawn the attention of an incurious generation to the fact that they had each ten fingers and ten toes, or that most of them had thirty-two teeth, distinguishable into masticators and incisors.

When, from these, and some other considerations, we had ventured to infer, that the knowledge derived from mere observation could scarcely make any addition to our power, Mr. Steward refers triumphantly to the instance of astronomy, and, taking it almost for granted, that all the discoveries in that science have been made by observation alone, direct the attention of his readers to the innumerable applications which may be made of it to purposes of unquestioned utility.

"la compensation," he observes, "for the inability of the astronomer to control those movements of which he studies the laws, he may boast, as I already hinted, of the immense accession of a more useful power which his discoveries have added to the human race, on the surface of their own planet. It would be endless to enumerate all the practical uses to which his labours are subservient. It is sufficient for me to repeat an old, but very striking reflection, that the only accurate knowledge which man possesses of the surface of the earth, has been derived from the previous knowledge he had acquired of the phenomena of the stars. Is it possible to produce a more apposite, or a more undeniable proof of the universality of Bacon's maxim, that 'knowledge is power,' than a fact which demonstrates the essential aid which man has derived, in asserting his dominion over this lower world, from a branch of science which seems, at first view, fitted only to gratify a speculative curiosity; and which, in its infancy, served to amuse the leisure of the Chaldean shepherd?" Prelim. Diss. p. xxxviii. xxxix.

To this we have to answer, in the first place, that astronomical science has not been perfected by observation alone; but that all the elements which have imparted to it the certainty, the simplicity, and the sublimity which it possesses, have been derived from experiments made upon substances in the power of their contrivers; from experiments performed with small pieces of matter on the laws of projectile motion-the velocities of falling bodiesand on centrifugal and centripetal forces. The knowledge of these laws, like all other valuable knowledge, was obtained by experiment only; and their application to the movements of the heavenly bodies was one of those splendid generalisations which derive their chief merit from those inherent imperfections of observation by which they were rendered necessary. But, in the second place, we must observe, that even holding astronomy to be a science of mere observation, the power which Mr. Stewart says we have obtained by means of it, is confessedly a power, not over the substances with which that science is conversant, but over other substances which stand in some relation to them; and to which, accordingly, that science is capable of being applied. It is over the earth and the ocean that we have extended our dominion by means of our knowledge of the stars. Now, applying this case to that of the philosophy of mind, and assuming, as we seem here entitled to assume, that it has invested us with no new power over mind itself, -what, we would ask, are the other objects over which our power is increased by means of our knowledge of mind? Is there any other substance to which that knowledge can possibly be applied? Is there any thing else that we either know better, or can dispose of more effectually, in consequence of our observations on our own intellectual constitution? It is evident, we humbly conceive, that these questions must be answered in the negative. The most precise knowledge which the metaphysician can acquire by reflecting on the subjects of his consciousness, can give him no new power over the mind in which he discovers those subjects; and it is almost a selfevident proposition, that the most accurate knowledge of the subjects of consciousness can give him no power over any thing but mind.

There is one other little point connected with this argument which we wish to settle with Mr. Stewart. In speaking of the useful applications that may be ultimately made of the knowledge derived from observation, we had said, that for the power or the benefit so obtained, mankind were indebted-not to the observer, but to him who suggested the application. Mr. Stewart admits the truth of this; but adds, that the case is exactly the same with the knowledge derived from experiment; and that the mere em– piric is on a footing with the mere observer. Now, we do not think the cases exactly the same; and it is in their difference that we conceive the great disadvantage of observation to consist. Whoever makes an experiment, must have the power at least to repeat that experiment, and, in almost every case, to repeat it with some variation of circumstances. Here, therefore,