From this cloud of teftimonies, to which hundreds might be added, I apprehend, that whatever cenfure is thrown upon those who have spoke of common fenfe as a principle of knowledge, or who have appealed to it in matters that are selfevident, will fall light, when there are so many to fhare in it. Indeed, the authority of this tribunal is too facred and venerable, and has prescription too long in its favour to be now wifely called in queftion. Those who are difpofed to do fo, may remember the fhrewd faying of Mr. Hobbes, "When reafon is against a man, a man will be against reafon." This is equally applicable to common fenfe.'

Dr. Reid then goes to explain it more particularly.

We afcribe to reafon two offices, or two degrees. The first is to judge of things felf-evident; the fecond to draw conclufions that are not felf-evide t from those that are. The firft of thefe is the province, and the fole province of common fenfe; and therefore it coincides with reafon in its whole extent, and is only another name for one branch or one degree of reafon. Perhaps it may be faid, why then fhould you give it a particu lar name, fince it is acknowledged to be only a degree of reafon it would be a fufficient anfwer to this, why do you abolish a name which is to be found in the language of all civilized nations, and has acquired a right by prescription? fuch an attempt is equally foolish and ineffectual. Every wife man will be apt to think, that a name which is found in all languages as far back as we can trace them, is not without fome ufe.

But there is an obvious reason why this degree of reafon Thould have a name appropriated to it; and that is, that in the greatest part of mankind no other degree of reafon is to be found. It is this degree that entitles them to the denomination of reafonable creatures. It is this degree of reason, and this only, that makes a man capable of managing his own affairs, and answerable for his conduct towards others. There is, therefore, the best reason why it should have a name appropri ated to it.

Thefe two degrees of reafon differ in other refpects, which would be fufficient to entile them to diftinct names.

The first is purely the gift of Heaven. And where Heaven has not given it, no education can fupply the want. The fecond is learned by practice and rules when the first is not wanting. A man who has common fenfe may be taught to reason. But if he has not that gift, no teaching will make him able either to judge o. firft principles, or to reason from them.

I have only this farther to obferve, that the province of common fenfe is more extenuve in refutation than in confirmation. A conclufion drawn by a irin of just reafon ng from true principles cannot pofiibly contradict any decifion of common fenfe, nec ufe truth will always be confiftent with itself. Neither can fuch a conclufion receive any confirmation from common fenie, becaule it is not within its jurifdiction.

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But it is poffible, that, by fetting out from falfe principles, or by an error in reasoning, a man may be led to a conclufion that contradicts the decifions of common fenfe. In this cafe, the conclufion is within the jurisdiction of common fenfe, though the reasoning on which it was grounded be not; and a man of common fenfe may fairly reject the conclufion, without being able to fhew the error of the reasoning that led to it.

Thus, if a mathematician, by a procefs of intricate demonstration, in which fome falfe ftep was made, fhould be brought to this conclufion, that two quantities, which are both equal to a third, are not equal to each other, a man of common fenfe, without pretending to be a judge of the demonftration, is well entitled to reject the conclufion, and to pronounce it abfurd."

We cannot give this paffage, in our opinion, a greater encomium, than by pronouncing it COMMON SENSE.

The fentiments of Philofophers on Judgment, as an Operation of the Mind, next follow; and we are from thence naturally led to firft principles in general, and those immediately derived from them, which have fometimes been raised to an equal rank, viz. contingent truths. In this enquiry our author, with great force, attacks Mr. Hume and bishop Berkeley on their doubts refpecting matter; and very conclufively points out the fource of their errors. This part of his work we have read with great pleasure, and are only sorry that its extent will neither allow us to tranfcribe or abridge it. The Effay is concluded by an account of Prejudices, and the Caufes of Error."

The seventh Essay is on Reasoning; and one principal part of it is an Enquiry whether Morality be capable of Demonftration.' In this point Dr. Reid differs from Mr. Locke, and thinks the instances which the latter has given relate rather to metaphyfical than moral truths. The obligation of the moft general rules of duty is felf-evident. If it be not perceived at once, no reasoning can make it clearer. When the application of thefe rules to particular actions requires reasoning, that reafoning must be rather of the probable than the demonftrative kind. Perhaps we have feen this probable mode carried to its greatest height, in Mr. Paley's late excellent work. The Effay concludes with an Examination of Mr. Hume's Scepticism with Regard to Reason, contained in the First Book of his Treatife on Human Nature; and Dr. Reid anfwers his doubts with great fuccefs.

The laft Effay is entitled Of Tafte.' It explains this power of the mind, and examines its objects, novelty, grandeur, and beauty.

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From a flight view of this analyfis, it will be easy to perceive that, in our limited circle, we could not have entered into a very extenfive detail of any one subject, or even had room to have expreffed our doubts, or to have produced any arguments relating to thofe opinions of our author, in which we could not fully agree with him. It is fufficient to have given a general account of the work, that those who are engaged in the fame purfuits, or pleafed with the fame enquiries, may know the kind of entertainment they will receive from it. We muft, in juffice, add, that we have generally agreed with Dr. Reid, and think these Effays a valuable addition to our ftock of metaphyfical knowledge. They are clear, judicious, and often fatisfactory. But the author will allow us alfo to add, that, in some instances, we think he has been lefs exact, and in one point more unfavourable to a refpectable author, than we wished him to be. A few words are alfo exceptionable dogmaticalnefs' for inftance, and fome fimilar ones, are not English, and have no intrinfic merit to induce us to receive them.

In the firft Effay, he feems improperly to distinguish an individual from a fpecies. This is a distinction without a difference; for an individual is always a fpecies or a variety, and confequently admits of a definition. London or Paris are fpecies of the genus city; and, if they are capable of being diftinguished by accidental circumftances of time and place,' they certainly are not incapable of a logical definition.

Dr. Hartley's Syftem of Vibrations is the subject of Dr. Reid's remarks and cenfure. We are convinced, on the contrary, that this mode of communication is fufficiently eftablished; at least our author's arguments against it do not carry conviction to our minds, or even raise any doubts.

As to the existence of vibratory motions in the medullary fubftance of the nerves and brain, the evidence produced is this: first, it is obferved, that the fenfations of feeing and hearing, and fome fenfations of touch, have fome fhort duration and continuance. Secondly, though there be no direct evidence that the fenfations of tafte and fmell, and the greater part of those of touch, have the like continuance; yet, fays the author, analogy would incline one to believe that they must resemble the fenfations of fight and hearing in this particular. Thirdly, the continuance of all our fenfations being thus eftablifhed, it follows, that external objects impress vibratory motions on the medullary fubftance of the nerves and brain; because no motion, befides a vibratory one, can refide in any part for a moment of time. This is the chain of proof, in which the first link is ftrong, being confirmed by experience; the fecond is very weak; and

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the third ill weaker. For other kinds of motion, belides that of vibration, may have fome continuance; fuch as rotation, bending or unbending of a fpring, and perhaps others which we are unacquainted with: nor do we know whether it is otion that is produced in the nerves; it may be preffure, attrac tion, repulfion, or fomething we do not know. i his indeed is the common refuse of all hypothefes, that we know no other way in which the phænomena may be produced, and, therefore, they must be produced in this way. There is, therefore, no proof of vibrations in the infinitefimal particles of the brain and

nerves.

It may be thought that the existence of an elaftic vibrating æther fands on a firmer foundation, having the authority of fir Ifaac Newton. But it ought to be observed, that although this great man had formed conjectures about this æther near fifty years before he died, and had it in his eye during that long fpace as a fubject of enquiry; yet it does not appear that he ever found any convincing proof of its exiftence, but confidered it to the laft as a queftion whether there be fuch an æther or not. In the premonition to the reader, prefixed to the second edition of his Optics, anno 1717, he expreffes himself thus with regard to it: "Left any one thould think that I place gravity among the effential properties of bodies, I have fubjoined one queftion concerning its caufe; a queftion, I fay, for I do not hold it as a thing established." If, therefore, we res gard the authority of fir Ifaac Newton, we ought to hold the existence of fuch an æther as a matter not established by proof, but to be examined into by experiments; and I have never heard that, fince his time, any new evidence has been found of its existence.'

We think the links' of this anfwer lefs ftrong than those of the proof; for the continued motion, from rotation,' is in confequence of a mechanical ftructure: the bending and unbending of a fpring are exactly the inftances that Dr. Hartley might have chofen; for the continuance of motion, and the vibrations, are the confequence of its elafticity. Preffure, attraction, and repulfion, cannot occafion this continued effect. We allow that Newton's æther has not yet been demonftrated; but our neighbours, who reject his mathematical proofs, yet agree in this question; and the general coincidence of opinion is of fome confequence. Indeed, in many enquiries both of natural philofophy and chemistry, the exiftence of fome intervening medium, of an elaftic nature, quocunque gaudet nomine,' is fo obvious, that we know an able philofopher who convinced himself of its exiftence by those enquiries which he undertook to difprove it. We differ too, from our author, in another part of this fubject: if an hypothefis explains the phænomena, without any contradictory ap

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pearances, we will not indeed contend that it must be true; but, for our own parts, we would not exchange the truth for it. If Dr. Reid will reflect, he will find that Des Cartes' Vortices are by no means equally fatisfactory. One part of his objections we fhall not touch on, for we fpeak only of the mode of communication to the brain; all beyond is doubt and uncertainty: it is only clear, that the impreffion made muft resemble, in its obvious properties, the manner in which

it is made.

Philofophers have accounted, in fome degree, for our various fenfations of found, by the vibrations of elastic air. But it is to be obferved, firft, that we know that fuch vibrations do really exift; and, fecondly, that they tally exactly with the moft remarkable phænomena of found. We cannot, indeed, fhow how any vibration fhould produce the fenfation of found. This must be refolved into the will of God, or into fome caufe altogether unknown. But we know, that as the vibration is ftrong or weak, the found is loud or low. We know, that as the vibration is quick or flow, the found is acute or grave. We can point out that relation of fynchronous vibrations which produces harmony or difcord, and that relation of fucceffive vibrations which produces melody and all this is not conjectured, but proved by a fufficient induction. This account of founds, therefore, is philofophical; although, perhaps, there may be many things relating to found that we cannot account for, and of which the causes remain latent. The connections defcribed in this branch of philofophy are the work of God, and not the fancy of men.

If any thing fimilar to this could be shown in accounting for all our fenfations by vibrations in the medullary substance of the nerves and brain, it would deferve a place in found philofophy. But, when we are told of vibrations in a substance, which no man could ever prove to have vibrations, or to be ca pable of them; when fuch imaginary vibrations are brought to account for all our fenfations, though we can perceive no correfpondence in their variety of kind and degree to the va riety of fenfations, the connections defcribed in fuch a fyftem are the creatures of human imagination, not the work of God. The rays of light make an impreffion upon the optic nerves; but they make none upon the auditory or olfactory. The vibrations of the air make an impreffion upon the auditory nerves; but none upon the optic or the olfactory. The effluvia of bodies make an impreffion upon the olfactory nerves; but make none upon the optic or auditory. No man has been able to give a fhadow of reason for this. While this is the cafe, is it not better to confefs our ignorance of the nature of those impreffions made upon the nerves and brain in perception, than to flatter our pride with the conceit of knowlege which we have

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