tion to the mind, follows naturally as a consequence of both."

"It is indeed," he continues, "a necessary consequence of both theories, that magnitude and figure do not exist in nature, or subsist externally, but that these are purely spiritual, or ideas in the mind: This, however, is the only point in which the two theories agree."* It would be altogether foreign to my present purpose to attempt to follow the very ingenious author through the elaborate exposition which he has given of the characteristical peculiarities of his own doctrine. I have studied it with all the attention in my power; but without being able fully to comprehend its meaning. As far as I can judge, the obscurity which hangs over it arises, in a great measure, from a mistaken connexion which Dr. Hutton had supposed between his own physical conclusions concerning hardness, or relative incompressibility, and Berkeley's metaphysical argument against the independent existence of things external. How clearly this distinction was seized by Boscovich, is demonstrated by a passage already quoted: And accordingly, it may be remarked, that, notwithstanding the numerous objections which have been made to the validity of his reasonings, none of his critics have refused him the praise of the most luminous perspicuity.

The truth is, that, while the conclusions of Boscovich and of Hutton, with respect to matter so far as hardness, or relative incompressibility is concerned, offer no violence to the common judgments of mankind, but only aim at a more correct and scientific statement of the fact than is apt to occur to our first hasty apprensions,—the assertion of Berkeley, that extension and figure have merely an ideal or (as Dr. Hutton calls it) a spiritual existence, tends to unhinge the whole frame of the human understanding, by shaking our confidence in those principles of belief which form an essential part of its constitution. But on this point I shall have an opportunity of explaining myself more fully, in the course of some observations which I propose to offer on the philosophy of Dr. Reid.

Hutton's Principles of Knowledge, Vol. I. p. 357.

CHAPTER SECOND.

SECTION FIRST.

On the Foundation of our Belief of the Existence of the material World, according to the Statement of Reid.-Strictures on that Statement.

I HAVE already said, that Reid's account of the existence of matter, although correct so far as it goes, does not embrace all the circumstances of the question. The grounds of this observation I shall endeavour to explain with all possible brevity: but before proceeding to the discussion, it is necessary for me to premise some remarks on a principle of our constitution, which may at first sight appear very foreign to the present argument; I mean, our belief of the permanence or stability of the order of nature.

That all our physical reasonings, and all those observations on the course of events, which lay the foundation of foresight or sagacity, imply an expectation, that the order of things will, in time to come, continue similar to what we have experienced it to be in time past,. is a fact too obvious to stand in need of illustration; but it is not equally clear, how this expectation arises at first in the mind. Mr. Hume resolves it into the association of ideas, which leads us, after having seen two events often conjoined, to anticipate the second, whenever we see the first ;-a theory to which a very strong objection immediately presents itself, That a single experiment is sufficient to create as strong a belief of the constancy of the result as ten thousand. When a philosopher repeats an experiment for the sake of greater certainty, his hesitation does not proceed from any doubt, that, in the same circumstances, the same phenomena will be exhibited; but from an apprehension, that he may not have attended duly to all the different circumstances in which the first experiment was made. If the second experiment should differ in its result from the first, he will not suspect that any change has taken

place in the laws of nature; but will instantly conclude, that the circumstances attending the two experiments have not been exactly the same.

It will be said, perhaps, that although our belief in this instance is not founded on a repetition of one single experiment, it is founded on a long course of experience with respect to the order of nature in general. We have learned, from a number of cases formerly examined, that this order continues uniform; and we apply this deduction as a rule to guide our anticipations of the result of every new experiment that we make. This opinion is supported by Dr. Campbell in his Philosophy of Rhetoric; but it seems to me to afford a very unsatisfactory solution of the difficulty. It plainly differs essentially from Mr. Hume's theory; for it states the fact in such a manner, as excludes the possibility of accounting for it by the association of ideas; while, at the same time it suggests no other principle, by means of which any plausible explanation of it may be obtained. Granting, at present, for the sake of argument, that after having seen a stone often fall, the associating principle alone might lead me to expect a similar event, when I drop another stone; the question still recurs, (supposing my experience to have been hitherto limited to the descent of heavy bodies)-Whence arises my anticipation of the result of a pneumatical, an optical, or a chemical experiment? According, therefore, to Campbell's doctrine, we must here employ a process of analogical reasoning. The course of nature has been found uniform in all our experiments concerning heavy bodies; and therefore we may conclude, by analogy, that it will also be uniform in all other experiments we may devise, whatever be the class of phenomena to which they may relate. It is difficult to suppose, that such a process of reasoning should occur to children or savages; and yet I apprehend, that a child who had once burned his finger with a candle, would dread the same result, if the same operation were to be repeated. Nor, indeed, would the case be different, in similar circumstances, with one of the lower animals.

In support of his own conclusion on this subject, Dr.

Campbell asserts,*" that experience, or the tendency of the mind to associate ideas under the notion of causes and effects, is never contracted by one example only." He admits, at the same time, that, in consequence of the analogical reasoning which I mentioned, natural philosophers consider a single experiment, accurately made, as decisive with respect to a theory. It is evident that, upon this supposition, children, and the vulgar, must see two events often conjoined, before they apprehend the relation of cause and effect to subsist between them; whereas the truth is, that persons of little experience are always prone to apprehend a constant connexion, even when they see a merely accidental conjunction. So firmly are they persuaded, that every change requires a cause, and so eager to discover it, that they lay hold of the event immediately preceding it, as something on which they may rest their curiosity; and it is experience alone that corrects this disposition, by teaching them caution in investigating the general laws which form a part of the order of the universe.t

From these observations, it seems to follow, that our expectation of the continuance of the laws of nature is not the result of the association of ideas, nor of any other principle generated by experience alone; and Mr. Hume has shown, with demonstrative evidence, that it cannot be resolved into any process of reasoning a priori. Till, therefore, some more satisfactory analysis of it

* Vol. 1. p. 137.

†The account which is given in the Encyclopædia Britannica of the conclusiveness of a single experiment in proof of a general law of nature is, at bottom, the very same with the theory of Campbell; and therefore a separate consideration of it is unnecessary. This will appear evident from the following extract.

"EXPERIMENTAL PHILOSOPHY seems, at first sight, in direct opposition to the procedure of nature in forming general laws." (The expression here is somewhat ambiguous; but the author plainly means,-in opposition to the natural procedure of the mind, in the investigation of general laws.) "These are formed by induction from multitudes of individual facts, and must be affirmed to no greater extent than the induction on which they are founded. Yet it is a matter of fact, a physical law of human thought, that one simple, clear, and unequivocal experiment, gives us the most complete confidence in the truth of a general conclusion from it to every similar case. Whence this anomaly? It is not an anomaly, or contradiction of the general maxim of philosophical investigation, but the most refined application of it. There is no law more general than this, that nature is constant in all her operations.' The judicious and simple form of our experiment insures us (we imagine) in the complete knowledge of all the circumstances of the event. Upon this supposition, and this alone, we consider the experiment as the faithful representative of every possible case of the conjunction."-(Article Philosophy, § 57. See also (in the same volume) article Physics, § 103.)

shall appear than has yet been proposed, we are unavoidably led to state it as an original law of human belief. In doing so, I am not influenced by any wish to multiply unnecessarily original laws or ultimate truths; nor by any apprehension of the consequences that might result from an admission of any one of the theories in question. They are all of them, so far as I can see, equally harmless in their tendency; but all of them equally unfounded and nugatory, answering no purpose whatever, but to draw a veil over ignorance, and to divert the attention, by the parade of a theoretical phraseology, from a plain and most important fact in the constitution of the mind.

In treating of a very different subject, I had occasion, in a former work,* to refer to some philosophical opinions of Mr. Turgot, coinciding nearly with those which I have now stated. These opinions are detailed by the author, at considerable length, in the article Existence of the French Encyclopédie; but a conciser and clearer account of them may be found in Condorcet's discourse, prefixed to his essay "On the application of analysis to the probability of decisions pronounced by a majority of votes." From this account it appears, that Turgot resolved" our belief of the existence of the material world" into our belief of the continuance of "the laws of nature; " or, in other words, that he conceived our belief, in the former of these instances, to amount merely to a conviction of the established order of physical events and to an expectation that, in the same combination of circumstances, the same event will recur. It has always appeared to me, that something of this sort was necessary to complete Dr. Reid's speculations on the Berkeleian controversy; for although he has shown our notions concerning the primary qualities of bodies to be connected, by an original law of our constitution, with the sensations which they excite in our minds, he has taken no notice of the grounds of our belief that these qualities have an existence independent of our perceptions. This belief (as I have elsewhere ob

* Philosophy of the Human Mind, vol. I. chap. iv. sect. 5.