tinguishing a thing, first, as what it is, and secondly, as what it is not, is, I apprehend, a very extraordinary way of discovering its nature." Indeed! And pray what other way would the Dr. prescribe of ascertaining the nature of any thing, than that of determining in the first place what it is in itself, and afterwards discriminating it from all other things that bear a resemblance to it? Suppose I wish to ascertain, as far as the human mind is able, the nature of man, must I not ascertain the properties that belong to him, and by comparing him with other animals, determine the distinguishing traits that separate him from them? The Dr. proceeds. “And if ideas are ideas or perceptions in our minds, and at the same time the modifications of matter in the bodies that cause such perception in us, it will be no easy matter to discourse of them intelligibly." How uncandid and illiberal is this stricture! Dr. Reid had before in this same essay been explaining Mr. Locke's doctrine about primary and secondary qualities in bodies. He could not have misconceived the meaning of this metaphysician. He could not have failed to discern that, in this part of his essay, he had reference to that distinction, and intended merely to inform us, that when he spoke of our perceptions of heat, cold, sweet, bitter, sound, taste, &c. as existing in the bodies themselves, he meant merely those qualities in the bodies, which are apt to excite such sensations in us. Is not this very intelligible to one not determined to misconstrue it, although, I will admit not as accurately expressed as it might be? Our ideas or perceptions, can never properly be denominated the modifications of matter in the bodies that cause such perceptions in us; but what has occasional inaccuracy and obscurity in the manner of expression to do with the tenor of a man's doctrine? In the same strain the Dr. continues his animadversions. The discovery of the nature of our ideas, is carried on in the next section, in a manner no less extraordinary. "Whatsoever the mind perceives in itself, or is the imme

diate object of perception, thought, or understanding, that I call idea; and the power to produce any idea in our mind, I call quality of the subject wherein that idea is. Thus a snow-ball having the power to produce in us the ideas of white, cold and round, the powers to produce those ideas in us, as they are in the snow-ball, I call qualities; and as they are sensations or perceptions in our understandings, I call them ideas; which ideas, if I speak of them sometimes as in things themselves, I would be understood to mean those qualities in the objects which produce them in us." Here Mr. Locke, inaccurate as his language is, fully and unequivocally explains his meaning. Yet this circumstance does not shield him from the reprehensions of the Dr. "I believe," says Dr. Reid," it will be difficult to find two paragraphs in the essay so unintelligible. Whether this is to be imputed to the intractable nature of ideas, or to the oscitancy of the author, with which he is very rarely chargeable, I leave the reader to judge. There are, indeed, several other passages in the same chapter, in which a like obscurity appears; but I do not choose to dwell upon them."

I can perceive nothing difficult or unintelligible in this language, except to those who are predetermined to misapprehend it. It is as if the author had said, when I speak of heat, cold, sweet, bitter, &c. conformably to vulgar notions, as existing in things themselves, which I admit to be only sensations or perceptions in us; I would be understood in this case to refer to those qualities or powers in objects, which are calculated to excite such sensations in us. Can any thing be more clear?

Again-"Taking it for granted," says the Dr. " that by the ideas of primary and secondary qualities, he means the sensations they excite in us, I observe that it appears strange, that a sensation should be the idea of a quality in body, to which it is acknowledged to bear no resemblance. If the sensation of sound be the idea of that vibration of a sound

ing body which occasions it, a surfeit may for the same reason, be the idea of a feast." An admirable argument in the first sentence, and a no less admirable similitude in the second! Such comparisons may excite a smile at the expense of Mr. Locke, among the ignorant and undiscerning; but the philosophical world will learn in time, duly to estimate such unmanly expedients. He might as well have said, "if the sensation of sound, be the idea of that vibration of a sounding body which occasions it, John Falstaff may, for the same reason, be the idea of a glass of sack." The Dr. thus concludes his account of the primary and secondary qualities in bodies. "From the account I have given of the various revolutions in the opinions of philosophers about primary and secondary qualities, I think it appears that all the darkness and intricacy, that thinking men have found in this subject, and the errors they have fallen into, have been owing to the difficulty of distinguishing clearly sensation from perception, what we feel from what we perceive." Here we see what wonders are expected to be wrought by this great discovery, and how modestly these authors are in the habit of speaking of their own pretensions!

CHAPTER VIII.

Simple ideas derived from Sensation and Reflection.

THE next point in the system of Mr. Locke, to which Dr. Reid has taken exception, and which it is our purpose to vindicate, is that in which the former maintains, that all our simple ideas must be derived through the inlets of sensation and reflection. By sensation, he means that power of the mind, by which we receive perceptions of the qualities of external bodies; and by reflection or consciousness the attention which the mind pays to its own operations. Now it is an established maxim in philosophy, that no more causes of things are to be admitted, than are both true and sufficient to explain the phenomena. Until, therefore, we shall discover some ideas which could not have gained access to the mind, through the inlets of sensation and reflection, but must evidently have had, in the language of Mr. Locke, another postern to be admitted by; the doctrine of this philosopher must be regarded as established. Let us hear what Dr. Reid has to say in refutation of it. In essay 1, ch. 3, of Active Powers, he speaks the following language—“ Mr. Locke having refuted the Cartesian doctrine of innate ideas, took up, perhaps, too rashly, an opinion that all our simple ideas are got either by sensation or by reflection; that is, by our external senses or by consciousness of the operations of our own minds. Through the whole of his essay he shows a fatherly affection to this opinion, and often strains very hard to reduce our simple ideas to one of these sources or both. Of this, several instances might be given, in his account of our idea of substance, of duration, of personal identity. Omitting these as foreign to the present subject, I shall

only take notice of the account which he gives of our idea of power." The opinion of Dr. Reid is, then, that our ideas of substance, duration, personal identity, and of power, form just exceptions from the principles of Mr. Locke, as they are not to be traced either to sensation or reflection, or to both. Let us proceed to state the ground of his objections, and see whether they be not susceptible of a satisfactory answer. It will be necessary to state anew the doctrine of Mr. Locke, that his objection may be comprehended, and as Dr. Reid has given a statement of that doctrine, sufficiently succint and accurate, we shall content ourselves at this time with exhibiting it in his own words. The sum of Mr. Locke's account of power, according to the Dr., is this-" Observing by our senses various changes in objects, we collect a possibility in one object to be changed, and in another a possibility of making that change, and so come by that idea which we call power. Thus we say, that fire has a power to melt gold, and gold has a power to be melted; the first he calls active, the second passive power. He thinks, however, that we have the most distinct notion of active power, by attending to the power which we ourselves exert, in giving motion to our bodies when at rest, or in directing our thoughts to this or the other object as we will. And this way of forming the idea of power, he attributes to reflection, as he refers the former to sensation." On this account of the origin of our idea of power, the Dr. makes two remarks—“ First, whereas he distinguishes power into active and passive, I conceive passive power is no power at all. He means by it the possibility of being changed. To call this power, seems to be a misapplication of the word. I do not remember to have met with the phrase passive power in any other good author. Mr. Locke seems to have been unlucky in inventing it; and it deserves not to be retained in our language. Perhaps he was unwarily led into it, as an opposite to active power. But I conceive we call certain powers active, to distinguish them