ceffary to suppose the existence of fomething intermediate, by which its perceptions are produced; to the latter, the various metaphorical expreffions of ideas, fpecies, forms, Shadows, phantafms, images; which, while they amused the fancy with fome remote analogies to the objects of our fenfes, did not directly revolt our reason, by presenting to us any of the tangible qualities of body. "It was the doctrine of ARISTOTLE, (fays Dr. "REID), that as our fenfes cannot receive external "material objects themselves, they receive their fpe"cies; that is, their images or forms, without the "matter; as wax receives the form of the feal, with❝out any of the matter of it. These images or forms, "impreffed upon the fenfes, are called fenfible fpecies ; "and are the objects only of the fenfitive part of "the mind: but by various, internal powers, they "are retained, refined, and fpiritualized, so as to be"come objects of memory and imagination; and, "at laft, of pure intellection. When they are ob. 66 jects of memory and of imagination, they get the "name of phantafms. When, by farther refinement, "and being stripped of their particularities, they be "come objects of science, they are called intelligible Species: fo that every immediate object, whether of "fenfe, of memory, of imagination, or of reasoning, "must be fome phantafm, or fpecies, in the mind " itself. 66 "The followers of Ariftotle, especially the school"men, made great additions to this theory; which "the author himself mentions very briefly, and with "an appearance of referve. They entered into large 66 difqui difquifitions with regard to the fenfible fpecies, "what kind of things they are; how they are sent "forth by the object, and enter by the organs of the "fenses; how they are preferved, and refined by "various agents, called internal fenfes, concerning "the number and offices of which they had many "controverfies *." 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 exift eternal and immutable ideas, which were prior to the objects of sense, and about which all fcience was employed; yet appear to have agreed with them in their notions coucerning the mode in which external objects are perceived. This, Dr. Reid infers, partly from the filence of Aristotle about any difference between himself and his master upon this point; and partly from a paffage in the seventh book of Plato's Republic; in which he compares the process of the mind in perception, to that of a person in a cave, who fees not external objects themselves, but only their fhadows t. "Two thousand years after Plato, (continues Dr. Reid,) Mr. Locke, who ftudied the operations of "the human mind fo much, and with fo great fuc"cess, represents our manner of perceiving external objects, by a fimilitude very much refembling that "of the cave." Methinks," fays he, "the under. "derstanding is not much unlike a clofet, wholly fhut 66 Effays on the Intellectual Powers of Man, P. 25. " from "from light, with only fome little opening left, to "let in external visible resemblances or ideas of things "without. Would the pictures coming into fuch a "dark room but stay there, and lie fo orderly as to "to be found upon occasion, it would very much re"femble the understanding of a man, in reference "to all objects of fight, and the ideas of them *." 66 "Plato's fubterranean cave, and Mr. Locke's dark "closet, may be applied with ease to all the systems "of perceptions that have been invented: for they "all fuppofe, that we perceive not external objects "immediately; and that the immediate objects of "perception, are only certain fhadows of the external objects. Those shadows, or images, which we im"mediately perceive, were by the ancients called fpe"cies, forms, phantafms. Since the time of Des "Cartes, they have commonly been called ideas † ; "and by Mr. Hume, impreffions. But all philofophers, from Plato to Mr. Hume, agree in this, "that we do not perceive external objects imme diately; and that the immediate object of percep"tion must be fome image present to the mind." On the whole, Dr. Reid remarks, "that in their fenti"ments concerning perception, there appears an uniformity, which rarely occurs upon fubjects of fo "abftrufe a nature ." The very short and imperfect view we have now taken, of the common theories of perception, is almost sufficient, without any commentary, to establish Locke on Human Understanding, book ii. chap. 11.§ 17. + See Note [B]. Reid, p. 116, 117. the the truth of the two general obfervations formerly made; for they all evidently proceed on a fuppofition, fuggested by the phenomena of phyfics, that there must of neceffity exift fome medium of communication between the objects of perception and the percipient mind; and they all indicate a fecret conviction in their authors, of the effential diftinction between mind and matter; which, although not rendered, by reflection, fufficiently precife and fatisfactory, to fhew them the abfurdity of attempting to explain the mode of their communication; had yet fuch a degree of influence on their speculations, as to induce them to exhibit their fuppofed medium under as mysterious and ambiguous a form as poffible, in order that it might remain doubtful, to which of the two predicaments, of body or mind, they meant that it fhould be referred. By refining away the groffer qualities of matter; and by allufions to fome of the most aerial and magical appearances it affumes, they endeavoured, as it were, to fpiritualize the nature of their medium; while, at the fame time, all their language concerning it, implied fuch a reference to matter, as was neceffary for furnishing a plaufible foundation, for applying to it the received maxims of natural philofophy. Another observation, too, which was formerly hinted at, is confirmed by the fame historical review; that, in the order of inquiry, the phenomena of vifion had first engaged the attention of philofophers; and had fuggefted to them the greater part of their language, with refpect to perception in general; and that, in confequence of this circumstance, the com mon modes of expreffion on the fubject, unphilofophical and fanciful at beft, even when applied to the fenfe of feeing, are, in the cafe of all the other senses, obviously unintelligible and felf-contradictory." As "to objects of fight," fays Dr. Reid, "I understand "what is meant by an image of their figure in the "brain but how fhall we conceive an image of "their colour, where there is abfolute darkness? "And, as to all other objects of fenfe, except figure "and colour, I am unable to conceive what is meant "by an image of them. Let any man fay, what he. "means by an image of heat and cold, an image of "hardness or foftnefs, an image of found, or smell, "or tafte. The word image, when applied to these objects of fenfe, has abfolutely no meaning." This palpable imperfection in the ideal theory, has plainly taken rife from the natural order in which the phenomena of perception prefent themselves to the curiofity. The mistakes, which have been fo long current in the world, about this part of the human constitution, will, I hope, juftify me for profecuting the subject a little farther; in particular, for illuftrating, at fome length, the first of the two general remarks already referred to. This fpeculation I enter upon the more willingly, that it affords me an opportunity of stating fore important principles with respect to the object, and the lin.its, of pha fophical inquiry; to which I fall frequently have occation to refer, in the course of the following difquifitions. |