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• From this cloud of tekrmonies, to which hundreds might be added, I apprehend, that whatever censure is thrown upon those who have spoke of common sense as a principle of knowa ledge, or who have appealed to it in matters that are selfevident, will fall light, when there are so many to share in it. Indeed, the authority of this tribunal is too sacred and venerable, and has prescription too long in its favour to be now wisely called in queition. Those who are disposed to do so, may remember the shrewd saying of wis Hobbes, “ When reason is against a man, a man will be against reason.” This is equally applicable to common sense.'
Dr. Reid then goes to explain it more particularly.
• We ascribe to reason two offices, or two degrees. The first is to judge of things feif-evident; the second to draw conclufions that are not self-evide at from those that are. The firit of these is the province, and the fole province of common sense ; and therefore it coincides with reason in its whole extent, and is only another name for one branch or one degree of reason. Perhaps it may be aid, why then should you give it a particular naine, since it is acknowledged to be only a degree of reafon? it would be a fufficient answer 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 such an attempt is equally foolith and ineffectual. Every wise man will be apt to think, that a name which is found in all languages as far back as we can trace thein, is not without some use.
• But there is an obvious reafon why this degree of reason should have a name appropriated to it; and that is, that in the greatest part of mankind no other degree of reason is to be found. It is this degree that entitles them to the denomination of realonable 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 appropria ated to it.
. Tnese two degrees of reason differ in other respects, which would be sufficient to entile thein to distinct names.
" The firit is purely the gift of Heaven. And where Heaven has not given it; nö education can supply the want. The fea cond is learned by practii e and rules, when the first is not wanta ing: A man who has common fente may be taught to reason. But if he has not that gift, no tea hing will make him able either to judge o first principles, or to reason from them.
'. I have only this father to observe, that the province of common senle is more ex enuve in refutation chan in confirma. tion. A conclusion drawn by a riin of just reasoning from true principles cannot poltibly contradict any decision of commou sef, Lecause truih will aiways be conlistent with itself. Neither can such a conclufion receive any confirmation from common senie, because it is not within its jurisdiction.
• But it is possible, that, by setting out from false principles, or by an error in reasoning, a man may be led to a conclusion that contradicts the decisions of common sense. In this case, the conclufion is within the jurisdiction of common sense, though the reasoning on which it was grounded be not; and a man of common sense may fairly reject the conclusion, without being able to shew the error of the reasoning that led to it.
• Thus, if a mathematician, by a process of intricate demonftration, in which some false step was made, hould be brought to this conclusion, that two quantities, which are both equal to a third, are not equal to each other, a man of common sense, without pretending to be a judge of the demonftration, is well entitled to reject the conclusion, and to pronounce it absurd.'
We cannot give this passage; in our opinion, a greater encomium, than by pronouncing it comMON SENSE.
• The sentiments of Philosophers on Judgment, as an Operation of the Mind, next follow ; and we are from thence naturally led to first principles in general, and those immediately derived from them, which have sometimes 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 respecting matter ; and very conclufively points out the source 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 transcribe or abridge it.
The Essay is concluded by an account of • Prejudices, and the Causes of Error."
The seventh Effay is on Reasoning; and one principal part of it is ‘ an Enquiry whether Morality be capable of Demonstration. In this point Dr. Reid differs from Mr. Locke, and thinks the instances which the latter has given relate rather to metaphysical than moral truths. The obligation of the most general rules of duty is self-evident. If it be not perceived at once, no reasoning can make it slearer. When the application of these rules to particular actions requires reasoning, that reasoning must be rather of the probable than the demonstrative kind. Perhaps we have seen this probable mode carried to its greatest height, in Mr. Paley's late excellent work. The Essay concludes with an Examination of Mr. Hume's Scepticism with Regard to Reason, contained in the First Book of his Treatise on Human Nature ; and Dr. Reid answers his doubts with great success.
The last Essay is entitled 'Of Taste.' It explains this power of the mind, and examines its objeĉts, novelty, grandeur, and beauty,
From a flight view of this analysis, it will be easy to perceive that, in our limited circle, we could not have entered into a very extensive detail of any one subject, or even had room to have expressed our doubts, or to have produced any arguments relating to those opinions of our author, in which we could not fully agree with him. It is sufficient to have given a general account of the work, that those who are engaged in the same pursuits, or pleased with the same enquiries, may know the kind of entertainment they will receive from it. We must, in justice, add, that we have generally agreed with Dr. Reid, and think these Essays a valuable addition to our stock of metaphysical knowledge. They are clear, judicious, and often satisfactory. But the author will allow us also to add, that, in some instances, we think he has been less exact, and in one point more unfavourable to a respectable au. thor, than we wished him to be. A few words are also exceptionable : dogmaticalness' for instance, and some fimilar ones, are not English, and have no intrinfic merit to induce us to receive them,
In the first Essay, he seems improperly to distinguish an individual from a species. This is a distinction without a difference; for an individual is always a species or a variety, and consequently admits of a definition. "London or Paris are species of the genus city ; and, if they are capable of being diftinguished by accidental circumstances of time and place,' they certainly are not incapable of a logical definition.
Dr. Hartley's System of Vibrations is the subject of Dr. Reid's remarks and censure. We are convinced, on the contrary, that this mode of communication is sufficiently established ; 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 medallary substance of the nerves and brain, the evidence produced is this: first, it is observed, that the sensations of seeing and hearing, and some sensations of touch, have some short dura. tion and continuance. Secondly, though there be no direct evidence that the sensations of taste and smell, and the greater part of those of touch, have the like continuance ; yet, says the author, analogy would incline one to believe that they must resemble the sensations of fight and hearing in this particular. Thirdly, the continuance of all our fenfations being thus eftablished, it follows, that external objects imprefs vibratory motions on the medullary substance of the nerves and brain; be. cause no motion, besides a vibratory one, can reside in any part for a moment of time.
• This is the chain of proof, in which the first link is strong, being confirmed by experience; the second is very weak; and
the third fill weaker. For other kinds of mo:ion, 'besides that of vibration, may have some continuance ; such as rotation, bending or unbending of a spring, and perhaps others which we are unacquainted with : nor do we know whe her it is motion that is produced in the nerves; it may he prellure, attrac, tion, repultion, or something we do not kuow. i his indeed is the common refule of all hysotheles, that we know no other way in which the phænomena muy be produd, and, therefore, they must be produced in this way. There is, therefore, no proof of vibrations in the infinitetin al particles of the brain and nerves.
may be thought that the ex stence of an elastic vibrating ather stands on a former foundation, having the au: hority of fir líaac Newton. But it ought to be observed, that although this great man had formed conjectures about th s æther near fifty years before he died, and had i: in his eye during that long space as a lubject of enquiry; yet it does not appear that he ever found any convincing proof of its existence, but considered it to the lait as a queition whether there be such an æther or not. In the premonition to the reader, prefixed to the second edition of his Optics, anno 1717, he expresses himtelf thus with regard to it: " Left any one should think that I place gravity among the effential properties of bodies, I have subjoined one question concerning its cause; a question, I fay, for I do not hold it as a thing established.” If, therefore, we ree gard the authority of fir Isaac Newton, we ought to hold the existence of such an æther as a matter not estabiilhed by proof, but to be examined into by experiments; and I have never heard that, since his time, any new evidence has been found of its existence,'
We think the links' of this answer less strong than those of the proof; for the continued motion, from rotation,' is in consequence of a mechanical structure : the bending and unbending of a spring are exactly the instances that Dr. Hartley might have chosen ; for the continuance of motion, and the vibrations, are the consequence of its elakicity. Pressure, attraction, and repulsion; cannot occasion this continued effeet. We allow that Newton's æther has not yet been demonstrated; but cur neighbours, who reject his mathematical froofs, yet agree in this question ; and the general coinci. dence of opinion is of some consequence. Indeed, in many enquiries both of natural philosophy and chemistry, the existence of some intervening medium, of an elastic nature, 'quecunque gaudet nomine,' is so obvious, that we know an able philosopher who convinced himself of its exiftence by tho e enquiries which he undertook to disprove it. We differ too, from our author, in another part of this subject : if an hypothesis explains the phænomena, without any contradi&tory ap. 4
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 shall 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 impression made must resemble, in its obvious properties, the manner in which it is made.
• Philosophers have accounted; in some degree, for our various sensations of sound, by the vibrations of elastic air. But it is to be observed, first, that we know that such vibrations do really exist and, fecondly, that they tally exactly with the most remarkable phænomena of found. We cannot, indeed, how how any vibration should produce the sensation of found. This must be resolved into the will of God, or into some cause altogether unknown. But we know, that as the vibration is strong or weak, the sound is loud or low. We know, that as the vibration is quick or slow, the sound is acute or grave. We can point out that relation of synchronous vibrations which produces harmony or discord, and that relation of fucceffive vibrations which produces melody: and all this is not conjectured, but proved by a fufficient induction. 'This account of sounds, therefore, is philosophical; although, perhaps, there may be many things relating to sound that we cannot account for, and of which the causes remain latent. The connections described in this branch of philosophy are the work of God, and not the fancy of men.
• If any thing similar to this could be shown in accounting for all our sensations by vibrations in the medullary subitance of the nerves and brain, it would deserve a place in found philosophy. But, when we are told of vibrations in a substance, which no man could ever prove to have vibrations, or to be capable of them; when such imaginary vibrations are brought to account for all our fenfations, though we can perceive no correspondence in their variety of kind and degree to the va. riety of sensations, the connections described in such a system are the creatures of human imagination, not the work of God.
· The rays of light make an impression upon the optic nerves ; but they make none upon the auditory or olfactory. The vibrations of the air make an impression upon the auditory nerves; but none upon the optic or the olfactory. The effluvia of bodies make an impression upon the olfactory nerves ; but make none upon the optic or auditory. No man has been able to give a shadow of reason for this. While this is the case, is it not better to confess our ignorance of the nature of those impresions made upon the nerves and brain in perception, than to fatter our pride with the conceit of knowlege which we