The confusion of Dr Reid's notions on this subject, seems to have arisen from a cause, which has been the chief source of the general confusion that prevails in intellectual science; and, indeed, it was principally with the view of exhibiting this confusion, and its source, to you strongly, that I have dwelt so long on a criticism, which, to those among you who are not acquainted with the extensive and important applications that have been made of this doctrine, may, perhaps, have appeared of very little interest. Dr Reid, it is evident, was not sufficiently in the habit of considering the phenomena of the mind,—its perceptions, as well as its remembrances, judgments, passions, and all its other affections, whatever these may be,—in the light in which I have represented them to you, merely as the mind affected, in a certain manner, according to certain regular laws of succession, but as something more mysterious than the subject of this sequence of feelings; for, but for this notion of something more mysterious, the object of perception, and the external occasion of that state of mind which we term perception, must have conveyed precisely the same notion. To have a clear view of the phenomena of the mind, as mere affections or states of it, existing successively, and in a certain series, which we are able, therefore, to predict, in consequence of our knowledge of the past, is, I conceive, to have made the most important acquisition which the intellectual inquirer can make. To say, merely, that it is to have learned to distinguish that which may be known, from that which never can be known, and which it therefore would be an idle waste of labour to attempt to discover,—would be to say far too little. It is to see the mind, in a great measure, as it is in nature, divested of every thing foreign, passing instantly from thought to thought, from sensation to sensation, in almost endless variety of states, and differing as completely from that cumbrous representation of it, which philosophers are fond of representing to us, as the planets revolving freely in the immense space of our solar system, differ from those mimic orbs, which, without any principle of motion in themselves, are, as it were, dragged along, in the complex mechanism of our orreries.
In objecting, however, to Dr Reid's notion of perception, I am far from wishing to erase the word from our metaphysical vocabulary. On the contrary, I conceive it to be a very convenient one, if the meaning attached to it be sufficiently explained, by an analysis of the complex state of mind, which it denotes, and the use of it confined rigidly to cases in which it has this meaning. Sensation may exist, without any reference to an external cause, in the same manner as we may look at a picture, without thinking of the painter; or read a poem, without thinking of the poet,—or it may exist with reference to an external cause; and it is convenient, therefore, to confine the term sensation to the former of these cases, and perception to the latter. But, then, it must be understood, that the perception is nothing but the suggestion of ideas associated with the simple sensation, as it originally took place,—or is only another name for the original simple sensation itself, in the cases, if any there be, in which sensation involves immediately in itself, the belief of some existence external to the sentient mind,—or is only a mere inference, like all our other inferences, if it arise, in the manner in which I have endeavoured to explain to you, how the notions of extension and resistance in an external cause of our feelings, might arise, and be afterwards suggested in association with other feelings that had frequently accompanied it.
To give a brief summary, however, of the argument which I have urged;—in that state of acquired knowledge, long after the first elementary feelings of infancy, in which modified state alone, the phenomena of the mind can become to us objects of reflective analysis, certain feelings are referred by us to an external material cause. The feelings themselves, as primarily excited, are termed sensations, and, when followed by the reference to an external cause, receive the name of perceptions, which marks nothing more in addition to the primary sensations, than this very reference. But what is the reference itself, in consequence of which the new name is given? It is the suggestion of some extended resisting object, the presence of which had before been found to be attended with that particular sensation, which is now again referred to it. If we had had no sense but that of smell; no sense but that of taste; no sense but that of sound; no sense but that of sight; we could not have known the existence of extended resisting substances, and, therefore, could not have referred the pleasant or painful sensations of those classes to such external causes, more than we refer directly to an external cause, any painful or pleasing emotion, or other internal affection of the mind. In all but one class of our sensations, then, it is evident that what Dr Reid calls perception, as the operation of a peculiar mental faculty, is nothing more than a suggestion of memory or association, which differs in no respect from other suggestions arising from other coexistences or successions of feelings, equally uniform or frequent. It is only in a single class of sensations, therefore,—that which Dr Reid ascribes to touch,—that perception, which he regards as a peculiar faculty, extending to all our sensations, can be said to have any primary operation, even though we should agree with him in supposing, that our belief of extended resistance is not reducible by analysis, to any more general principles. If, however, my analysis of the complex notion of matter be just, perception, in its relation to our original sensations of touch, as much as in relation to the immediate feelings which we derive from smell, taste, sight, and hearing, is only one of the many operations of the suggesting or associating principle. But, even on his own principles, I repeat, it must be confined to the single class of feeling, which he considers as tactual, and is not an original principle, coextensive with all the original varieties of sensation. Even in the single class, to which it is thus, on his own principles, to be confined, it is not so much what he would term a faculty, as an intuitive belief, by which we are led irresistibly, on the existence of certain sensations, to ascribe these to causes that are external and corporeal; or, if we give the name of faculty to this peculiar form of intuition, we should give it equally to all our intuitions, and rank among our faculties, the belief of the continued order of Nature, or the belief of our own identity, as much as our belief of external things, if our senses themselves are unable to give us any information of them.
Footnotes
[107] Account of the Life, &c. p. xci. prefixed to Reid's Works. Edin. 1803.
[108] Gray, de Princip. Cogit. Lib. I. v. 143—153.
[109] On the Intellectual Powers, Essay II. c. 16.
[111] On the Intellectual Powers, Essay II. c. 8.
[112] Ibid.