This passage, like several others in the work before us, is replete with error. In the first place, it is asserted that the effects of heat in expanding and decomposing bodies, are made known by the sense of sight, while its existence as a separate body is ascertained by a process of reasoning. But the truth is, both are made known by one and the same process. Heat produces a certain effect upon our senses, upon our minds; and we are so constituted that we cannot help conceiving of its separate existence. It affects us also through the medium of the changes it produces in other substances, as well as by its more immediate action upon the senses; and the same principle of suggestion which operated in the former case, forces the conviction upon the mind that an external change must have been the cause of this internal affection. Again, it is supposed that light, heat, and so forth, considered as separate substances or agents, are the proper objects of Natural Philosophy. But it is well known that in this respect Natural Philosophy has nothing at all to do with them. The effects, the changes, the phenomena, produced by these substances upon our minds, constitute the whole range of those objects about which Natural Philosophy is conversant.

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But the error of his supposed inquirer, is not what Lord Brougham thought it to be it does not consist in having adopted a principle of classification which would reduce all the objects of Natural Philosophy to the second class, but which would indeed leave them all in the first class, or those observed by the eye of consciousness :-It consists in having adopted a principle which would arrange all the objects of Natural Philosophy in one class, and those only in the second class that have been wholly excluded from the province of Natural Philosophy by our best philosophers.

We shall now proceed to notice a still more serious defect in this part of our author's work,-a defect, indeed, which runs through the whole discourse, and is the source of great confusion and perplexity. We allude to the substitution of a process of reasoning for the operation of a fundamental law of belief. Thus, the existence of an external substance is said to be ascertained by a process of reasoning; whereas it only makes an impression upon our senses and minds, and we cannot help believing in its separate existence as the cause of the impression. This principle of our constitution, which has been called a fundamental law of belief, and which is very distinct from the faculty of reason, is not recognized by our author. A process of reasoning is uniformly made to usurp its place and office. In every process of reasoning, there is, ac

cording to Lord Brougham's own admission, a comparison of ideas; but in the process by which we become acquainted with the existence of matter and of mind, there is no comparison of ideas whatever, and consequently no process of reasoning. One idea is suggested by another, but there is no comparison between them. The latter process is voluntary; the former is spontaneous and irresistible."

If his Lordship had seized upon this principle of our mental constitution, about which so much has been said, under different names, by modern writers, his argument might have been far more clear and satisfactory. But he has taken no notice of it whatever, and without it, every system of Natural Theology must be radically defective in its evidence. By excluding it from his treatise, he has rendered an essential disservice to the very cause which he has so zealously espoused. For it is well known by those who are acquainted with the speculations of Hume, and the discussions to which they gave rise, that experience and reasoning alone cannot constitute a sound basis of evidence for the truths of Natural Theology.

On this point let us quote the following from Dugald Stewart :

"Among those who have denied the possibility of tracing design from its effects, Mr. Hume is the most eminent, and he seems to have considered his reasonings on this subject as forming one of the most splendid parts of his philosophy; according to him all such inferences are inconclusive, being neither demonstrable by reasoning nor deducible from experience.

"In examining Mr. Hume's argument on this subject, Dr. Reid admits that the inferences we make of design from its effects are not the result of reasoning or experience; but still he contends such inferences may be made with a degree of certainty equal to what the human mind is able to attain in any instance whatever. The opinions we form of the talents of other men, nay, our belief that other men are intelligent beings, are founded on the very inference of design from its effects. Intelligence and design are not objects of our senses; and yet we judge of them every moment from external conduct and behaviour, with as little hesitation as we pronounce on the existence of what we immediately perceive.

"While Dr. Reid contends in this manner for the authority of this important principle of our constitution, he bestows due praise on Mr. Hume for the acuteness with which he has exposed the inconclusiveness of the common demonstrations of the existence of a designing cause, to be found among the

writers on natural religion; and he acknowledges the service that, without intending it, he has thereby rendered to the cause of truth; inasmuch as, by the alarming consequences he deduces from his doctrine, he has invited philosophers to an accurate examination of a subject which had formerly been considered in a very superficial manner, and has pointed out to them indirectly the true foundation on which this important article of our belief ought to be placed."

There is only one way in which the truths of Natural Theology can be shown to rest upon a sound and immutable basis. This way has been pointed out indirectly by Hume, and intentionally by Reid. Yet this way has been overlooked by Lord Brougham, although to make it known to others is the proposed object of his Discourse! Is it not surprising, that in an attempt to place Natural Theology upon a sure footing, he should have carried her back to that position from which she had already been dislodged; and that, too, after the discussions of others had so clearly shown the only grounds upon which her claims to certainty can be vindicated? "It is good," says Chalmers," to know what be the strong positions of an argument, and to keep by them-taking up our intrenchment there -and willing to relinquish all that is untenable."

We

Having mentioned Dr. Chalmers, it may be proper to notice his opinion respecting the answer of Reid and Stewart to the atheistical argument of Mr. Hume. As far as his censure goes in regard to the error of Reid, in unnecessarily multiplying first principles, we concur with him; but there is no echo in our heart to the language in which he accuses these philosophers of having "conjured up" certain principles, before unheard of, for the sole purpose of refuting Mr. Hume. consider the proceeding of Dr. Chalmers as a stronger confirmation of the opinion we have advanced, than if he had borne direct testimony to it; for, after having denounced the attempt of Reid and Stewart to invalidate the argument of the atheist, and proposed to meet Mr. Hume on his own ground, he is, nevertheless, compelled to resort to a first principle, or fundamental law of belief, in order to accomplish his purpose. Indeed, if he had attempted to answer Mr. Hume upon his own ground as he proposed, his argument would have been incomplete and untenable. And if this were the proper place, we might easily show that his argument, though different in words and form, is yet substantially the same with that of Mr. Stewart.

The second section of Lord Brougham's book contains a comparison between the physical branch of Natural Theolo

gy and Physics. In accordance with the main design of his work, it is the object of this part of it to show that the proofs of an intelligent and designing first cause, gathered from the world of matter, partake of the nature of inductive evidence; or, in other words, that this department of Natural Theology and Physics rest upon one and the same basis of induction. It is necessary to bear this in mind; for we cannot obtain a clear idea as to how the purpose of our author is accomplished unless we keep that purpose steadily in view.

We are informed that the two paths of investigation compared in this section are, to a very considerable extent, identical. The same induction of facts which leads us to a knowledge of the structure of the eye, and its functions in the animal economy, leads us to a knowledge of its adaptation to the properties of light. It is a truth of Physics, in the strictest sense of the word, that vision is formed by the eye refracting light, and making it converge to a focus upon the retina; and that the peculiar combination of lenses, and the different materials they are composed of, correct the indistinctness which would otherwise arise from the different refrangibility of light; in other words, makes the eye an achromatic instrument.

In this passage, and in what follows, we are struck with that confusion of thought and language to which we have already alluded. We shall now notice it again once for all; and, having put the reader sufficiently on his guard, we shall excuse ourselves from such minute criticism. We have seen, then, that it is a truth of physics, in the strictest sense of the word, that the eye is an optical instrument possessing achromatic properties. But the writer seems to doubt whether this is not also a truth of the physical branch of Natural Theology: he appears to incline, however, to the contrary opinion. "If this is not also a truth of Natural Theology, it is a position from which, by the shortest possible process of reasoning, we arrive at a theological truth-namely, that the instrument so successfully performing a given service by means of this curious structure, must have been formed with a knowledge of the properties of light." In the next sentence but one, however, his doubt vanishes, and he is positive that the eye's being an optical instrument is a truth of Natural Theology. Lest we should misrepresent, we will give his own words: "Upon the same evidence which all natural science rests on, reposes the knowledge that the eye is an optical instrument: this is a truth common both to Physics and Theology." And here it will be observed too, that the process of reasoning by which we pass over from a disclosure of physics to the correspond

ing truth in Natural Theology, is identified with the process of induction by which the discovery in physics was made: and, indeed, these two processes are frequently confounded in the present discourse. But what sort of reasoning is that which expresses itself in the form, "this instrument must have been made with a knowledge of the properties of light?" We think it would puzzle any one but Lord Brougham to answer this question; and as he attempts to do so, we shall presently examine his answer. Our object at this moment is to notice, how with the author a truth belongs now to physics in the strictest sense of the word; and, by founding a process of reasoning upon it, we deduce a truth of Natural Theology but the next moment this truth is no longer confined to physics, but it has made its way over into Natural Theology. One moment, and two truths are distinct, belonging to different departments of knowledge; the next, they are truths in both Physics and Theology." In one breath, a truth is said to rest upon induction, and in the next it is the result of "a process of reasoning founded upon induction." And this process of reasoning (which is no process of reasoning at all) is called induction no less than that upon which it is founded. In closely examining the discourse before us, we have often found ourselves in the midst of such confusion; and it has greatly increased the difficulty as well as the necessity of reviewing it. It has increased the necessity of a strict criticism, because this perplexity and obscurity, being united with a great display of knowledge, often give an appearance of depth and originality, where there is in truth little more than the profound entanglements of vacillating and contradictory views.

We agree with Lord Brougham that it is a truth in Physics, strictly speaking, that the structure of the eye is adapted to the properties of light, and that it is an achromatic instrument. From these facts, belonging to physical science, we deduce a truth which belongs to Natural Theology. Now, the question here arises, by what process is this last truth ascertained? By what step, or steps, do we pass from the discoveries of physical science to the conclusions of Theology?

According to Lord Brougham, as we have seen, this transition is made by induction, or by a process of reasoning. The process of reasoning here alluded to, is formally stated on the next leaf; so that we are left in no doubt as to the author's meaning. "The question which the Theologian always puts upon each discovery of a purpose manifestly accomplished is this suppose I had this operation to perform by mechanical means, and were acquainted with the laws regulating the ac