ELEMENTS OF THE PHILOSOPHY OF THE HUMAN MIND. CHAPTER FIRST. OF THE POWERS OF EXTERNAL PERCEPTION. SECTION I. Of the Theories which have been formed by Philofophers, to explain the manner in which the MIND perceives external Objects. AMONG the various phenomena which the human mind presents to our view, there is none more calculated to excite our curiosity and our wonder, than the communication which is carried on between the fentient, thinking, and active principle within us, and the material objects with which we are furrounded. How little foever the bulk of mankind may be difpofed to attend to fuch inquiries, there is fcarcely a perfon to be found, who has not occafionally turned his thoughts to that myfterious influence, which the will poffeffes over the members of the body; and to thofe powers of perception, which feem to inform us, by a fort of infpiration, of the various changes which take place in the external universe. Of those who receive the advantages of a liberal education, there are perhaps few, who pafs the period of childhood, without feeling their curiofity excited by this incomprehenfible communication between mind and matter. For my own part, at least, I cannot recollect the date of my earliest fpeculations on the subject. It is to the phenomena of perception alone, that I am to confine myfelf in the following effay; and even with respect to thefe, all that I propofe, is to offer a few general remarks on fuch of the common miftakes concerning them, as may be moft likely to iniflead us in our future inquiries. Such of my readers as wish to confider them more in detail, will find ample fatisfaction in the writings of Dr. Reid. In confidering the phenomena of perception, it is natural to fuppofe, that the attention of philofophers would be directed, in the firft inftance, to the sense of feeing. The variety of information and of enjoyment we receive by it; the rapidity with which this information and enjoyment are conveyed to us; and above all, the intercourfe it enables us to maintain with the more diftant part of the universe, cannot fail to give it, even in the apprehenfion of the most careless obferver, a pre-eminence over all our other perceptive faculties. Hence it is, that the various theories, which have been formed to explain the operations of our senses, have a more immediate reference to that of feeing; and that the greater part of the metaphyfical language, concerning perception in general, appears evidently, from its etymology, to have been fuggefted by the phenomena of vifion. Even when applied to this fenfe, indeed, it can at most amuse the fancy, without conveying any pre cife knowledge; but, when applied to the other fenfes, it is altogether abfurd and unintelligible. It would be tedious and utelefs, to confider particularly, the different hypothefis which have been advanced upon this fubject To all of them, I apprehend, the two following remarks will be found applicable: Firft, that, in the formation of them, their authors have been influenced by fome general maxims of philofophifing, borrowed from phyfics; and, fecondly, that they have been influenced by an indiftinct, but deep-rooted, conviction, of the immateriality of the foul; which, although not precife enough to point out to them the abfurdity of attempting to illuftrate its operations by the analogy of matter, was yet fufficiently ftrong, to induce them to keep the abfurdity of their theories as far as poffible out of view, by allufions to those physical facts, in which the diflinctive properties of matter are the leaft grofsly and palpably expofed to our observation. To the former of thefe circumstances, is to be afcribed, the general principle, upon which all the known theories of perception proceed; that, in order to explain the intercourfe between the mind and dif tant objects, it is necessary to suppose the existence of fomething intermediate, by which its perceptions are produced; to the latter, the various metaphorical expreffions of ideas, fpecies, forms, fhadows, phantafms, images; which, while they amused the fancy with fome remote analogies to the objects of our fenfes, did not directly revolt our reafon, by prefenting to us any of the tangible qualities of body. "It was the doctrine of Ariftotle, (fays Dr. Reid) "that, as our fenfes connot receive external materi al objects themselves, they receive their species; "that is, their images or forms, without the mat"ter; as wax receives the form of the feal, "without any of the matter of it. Thefe images "or forms, impreffed upon the fenfes, are called fen fible fpecies; and are the objects only of the fenfi❝tive part of the mind: but by various, internal powers, they are retained, refined, and fpirituali"zed, fo as to become objects of memory and imagination; and at laft, of pure intellection. When "they are objects of memory and imagination, they "get the name of phantafms. When, by farther re"finement, and being ftripped of their particulari"ties, they become objects of science, they are cal"led intelligible fpecies: fo that every immediate ob. "ject, whether of fenfe, of memory, of imagination, "or of reafoning, muft be fome phantafm, or fpe"cies, in the mind itself. "The followers of Ariftotle, especially the schoolmen, made great additions to this theory; which "the author himself mentions very briefly, and with "an appearance of referve. They entered into large "difquifitions with regard to the fenfible fpecies, "what kind of things they are; how they are fent "forth by the object, and enter by the organs of the "fenses; how they are preferved, and refined by va"rious agents, called internal fenfes, concerning the "number and offices of which they had many con"troverfies."* The Platonists, too, although they denied the great doctrine of the Peripatetics, that all the objects of human understanding enter at first by the fenfes and maintained, that there exist eternal and immutable ideas, which were prior to the objects of sense, and about which all science was employed; yet appear to have agreed with them in their notions concerning the mode in which external objects are per. ceived. This, Dr. Reid infers, partly from the fi lence of Ariftotle about any difference between himfelf and his mafter upon this point; and partly from a paffage in the feventh book of Plato's Republic; in which he compares the process of the mind in per* Essays on the Intellectual Powers of Man, p. 25. I ception, to that of a perfon in a cave, who fees not external objects themselves, but only their fhadows.* 66 "Two thousand years after Plato, (continues Dr. "Reid,) Mr. Locke, who ftudied the operations of "the human mind fo much, and with fo great fuccefs, reprefents our manner of perceiving external objects, by a fimilitude very much resembling that "of a cave." Methinks," fays he, "the understanding is not much unlike a closet, wholly fhut "from light, with only fome little opening left, to "let in external vifible refemblances or ideas of things without. Would the pictures coming into "fuch a dark room but ftay there, and lie fo orderly "as to be found upon occafion, it would very much "refemble the understanding of a man, in reference "to all objects of fight, and the ideas of them."t "Plato's fubterranean cave, and Mr Locke's dark "clofet, may be applied with ease to all the fyftems "of perception, that have been invented: for they “all suppose, that we perceive not external objects "immediately; and that the immediate objects of "perception, are only certain fhadows of the exter"nal objects. Those fhadows, or images. which we "immediately perceive, were by the ancients called r fpecies, forms, phantafms. Since the time of Des "Cartes, they have commonly been called ideas; ‡ "and by Mr. Hume, impreffions. But all the philof"ophers, from Plato to Mr. Hume, agree in this, "that we do not perceive external objects immediately; and that the immediate object of percep"tion must be fome image prefent to the mind.” On the whole, Dr. Reid remarks, "that in their "fentiments concerning perception, there appears "an uniformity, which rarely occurs upon fubjects "of fo abftrufe a nature."S 66 * Ibid. p. 99. + Locke on Human Understanding, book ii. chap. 11. § 17. |