clufion, that, without our organs of fenfe, the mind must have remained deftitute of knowledge, this conceffion could have no tendency whatever to favour the principles of materialifm; as it implies nothing more than that the impreffions made on our fenfes by ex ternal objects, furnish the occafions on which the mind, by the laws of its conftitution, is led to per ceive the qualities of the material world, and to exert all the different modifications of thought of which it is capable.

From the very flight view of the fubject, however, which has been already given, it is fufficiently evident, that this doctrine, which refers the origin of all our knowledge to the occafions furnished by sense, muft, be received with many limitations. That thofe ideas, which Mr. Locke calls ideas of reflexion, (or, in other words, the notions which we form of the fubjects of our own confcioufnefs,) are not fuggefted to the mind immediately by the fenfations arifing from the ufe of our organs of perception, is granted on all hands; and, therefore, the amount of the doctrine now mentioned, is nothing more than this; that the firft occafions on which our various intellectual faculties are exercised, are furnished by the impreffions made on our organs of fenfe; and confequently, that, without these impreffions, it would have been impoffible for us to arrive at the knowledge of our faculties. Agree. ably to this explanation of the doctrine, it may undoubtedly be faid with plaufibility, (and, I am inclined to believe, with truth,) that the occafions on which all our notions are formed, are furnished either immediately or ultimately by fenfe; but, if I am not

much mistaken, this is not the meaning which is commonly annexed to the doctrine, either by its advocates or their opponents. One thing at least is obvious, that, in this fenfe, it does not lead to those confequences which have interested one party of philofophers in its defence, and another in its refu

tation.

There is another very important confideration which deferves our attention in this argument: that, even on the fuppofition that certain impreffions on our organs of fense are neceffary to awaken the mind to a consciousness of its own existence, and to give rife to the exercise of its various faculties; yet all this might have happened, without our having any knowledge of the qualities, or even of the existence, of the material world. To facilitate the admiffion of this propofition, let us fuppofe a being formed in every other respect like man; but poffeffed of no senses, excepting those of hearing and smelling. I make choice of these two fenfes, because it is obvious, that by means of them alone we never could have arrived at the knowledge of the primary qualities of matter, or even of the existence of things external. All that we could poffibly have inferred from our occafional fenfations of fmell and found, would have been, that there existed fome unknown cause by which they were produced.

Let us fuppofe then a particular fenfation to be excited in the mind of fuch a being. The moment this happens, he muft neceflarily acquire the knowledge of two facts at once: that of the existence of the fenfation; and that of his own existence, as a fentient

being. After the fenfation is at an end, he can remember he felt it; he can conceive that he feels it again. If he has felt a variety of different fenfations, he can compare them together in respect of the pleafure or the pain they have afforded him; and will naturally defire the return of the agreeable fenfations, and be afraid of the return of those which were painful. If the fenfations of fmell and found are both excited in his mind at the fame time, he can attend to either of them he chufes, and withdraw his attention from the other; or he can withdraw his attention from both, and fix it on fome fenfation he has felt formerly. In this manner, he might be led, merely by fenfations exifting in his mind, and conveying to him no information concerning matter, to exercise many of his moft important faculties; and amidst all these different modifications and operations of his mind, he would feel, with irresistible conviction, that they all belong to one and the fame fentient and intelligent being; or, in other words, that they are all modifications and operations of himself.-I say nothing, at prefent, of the various fimple notions, (or fimple ideas, as they are commonly called,) which would arise in his mind; for example, the ideas of number, of duration, of caufe and effect, of perfonal identity; all of which, though perfectly unlike his fenfations, could not fail to be fuggested by means of them. Such a being, then, might know all that we know of mind at prefent; and as his language would be appropriated to mind folely, and not borrowed by analogy from material phenomena, he would even

poffefs important advantages over us in conducting the study of pneumatology.

From thefe obfervations it fufficiently appears, what is the real amount of the celebrated doctrine, which refers the origin of all our knowledge to our fenfations; and that, even granting it to be true, (which, for my own part, I am difpofed to do, in the fenfe in which I have now explained it), it would by no means follow from it, that our notions of the operations of mind, nor even many of thofe notions which are commonly fuggefted to us, in the firft inftance, by the ception of external objects, are necessarily fubfequent to our knowledge of the qualities, or even of the existence, of matter.

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The remarks which I have offered on this doctrine, will not appear fuperfluous to thofe who recollect that, although it has, for many years paft, been a fubject of controverfy in England, it continues ftill to be implicitly adopted by the beft philofophical writers in France; and that it has been employed by fome of them to fupport the fyftem of materialism; and by others to fhew, that the intellectual diftinctions between man and brutes, arife entirely from the differ ences in their animal organization, and in their powers of external perception.

CHAPTER SECOND.

Of Attention.

WHEN we are deeply engaged in converfation, or

occupied with any speculation that is interesting to the mind, the furrounding objects either do not produce in us the perceptions they are fitted to excite ; or these perceptions are inftantly forgotten. A clock, for example, may ftrike in the fame room with us, without our being able, next moment, to recollect whether we heard it or not.

In these, and fimilar cafes, I believe, it is commonly taken for granted, that we really do not perceive the external object. From fome analogous facts, however, I am inclined to suspect that this opinion is not well-founded. A perfon who falls afleep at church, and is fuddenly awaked, is unable to recollect the last words fpoken by the preacher; or even to recollect that he was fpeaking at all. And yet, that fleep does not fufpend entirely the powers of perception, may be inferred from this, that if the preacher were to make a fudden pause in his difcourfe, every perfon in the congregation who was afleep, would inftantly awake. In this cafe, therefore, it appears, that a person may be conscious of a perception, without being able afterwards to recollect it.

Many other instances of the fame general fact might be produced. When we read a book, (efpecially in

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