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“pears to me to have suffered himself to be misled in the very “foundation of it, merely by philosophers happening to call “ideas the images of external things; as if this was not known “to be a figurative expression, denoting, not that the actual shapes * of things were delineated in the brain, or upon the mind, but “only that impressions of some kind or other were conveyed to “ the mind by means of the organs of sense and their correspond“ing nerves, and that between these impressions and the sensa“tions existing in the mind, there is a real and necessary, though “at present an unknown connection.”
To those who have perused the metaphysical writings of Berkeley and of Hume, the foregoing passage cannot fail to appear much too ludicrous to deserve a serious answer. Do not all the reasonings which have been deduced from Locke's philosophy against the independent existence of the material world hinge on that very principle which Priestley affects to consider as merely an accidental mode of speaking, never meant to be understood literally Where did he learn that the philosophers who have “happened to call ideas the images of external things,” employed this term “as a figurative expression, denoting, not that the actual “shapes of things were delineated in the brain or upon the mind, “ but only, that impressions of some kind or other were conveyed “ to the mind by means of the organs of sense and their correspond“ing nerves ** Ilas not Mir Locke expressly told us, that “the “ideas of primary qualities of bodies are resemblances of them, “ and that their patterns do really exist in the bodies themselves; “but that the ideas produced in us by secondary qualities have ** no resemblance of them at all ”* Aud did not Mir Hume understand this doctrine of 1.ocke in the most strict and literal meaning of the words when he stated, as one of its necessary consequences, “That the mind either is no substance, or that it ** is an extended and divisible substance; because the ideas of “extension cannot be in a subject which is indivisible and unex** tended.” +
* Vol. I. p. 99, 13th edit. of his Essay.
f “The most vulgar philosophy informs us, that no external object can “make itself known, to the mind immediately, and without the interposition “ of an image or perception. That table, which just now appears to ine, is “only a perception, and all its qualities are qualities of a perception. Now, “the most obvious of all its qualities is extension. The perception consists “ of parts. These parts are so situated, as to afford us the motion of distance “ and contiguity; of length, breadth, and thickness. The termination of these “three dimensions is what we call figure. This figure is moveable, separable, “ and divisible. Mobility and separability are the distinguishmg properties “ of extended objects. And to cut short all disputes, the very idea of exten“sion is copied from nothing but an impression, and, consequently, must per“fectly agree to it. To say the idea of extension agrees to any thing, is to * say it is extended.”
“The free-thinker may now triumph in his turn; and having found there
But why should I refer, on this occasion, to Hume or to Locke, when quotations to the very same purpose are furnished by various writers of a much later date 2 The following is from a book published in 1782: “ It will not be disputed, but that sensations or ideas proper“ly exist in the soul, because it could not otherwise retain them “so as to continue to perceive and think after its separation from “ the body. Now, whatever ideas are in themselves, they are “evidently produced by external objects, and must therefore “ correspond to them; and since many of the objects or arche“types of ideas are divisible, it necessarily follows, that the ideas “ themselves are divisible also. The idea of a man, for instance, “could in no sense correspond to a man, which is the archetype “ of it, and THE REFoRE could Not BE THE IDEA of A MAN “if it did not consist of the ideas of his head, arms, trunk, legs, “&c. It therefore consists of parts, and consequently is divi“sible. And how is it possible, that a thing (be the nature of “ it what it may) that is divisible, should be contained in a sub“stance, be the nature of it likewise what it may, that is indivi** sible 2 “ it the archetypes of ideas have extension, the ideas expressive “ of them must have extension likewise ; and therefore the mind, “ in which they exist, whether it be material or immaterial, must “ have extension also.” It will surprise and amuse some of my readers, as a specimen of the precipitation and inconsistency of Dr Priestley, when they learn, that the passage just quoted is extracted from his disquisitions of matter and spirit, published eight years after his attack on Dr Reid. No form of words could have conveyed a more unqualified sanction than he has here given to the old hypothesis concerning ideas —a hypothesis which he had before asserted to have been never considered by any philosopher, but as a figurative mode of expression ; and which, when viewed in the light of a theory, he had represented as an absurdity too palpable to deserve a serious refutation. The ignorance which Priestley, and his associates of the Hartleian school, have discovered of the history of a branch of philosophy which they have presumed to decide upon with so much dogmatism, renders it necessary for me to remark once more, in this place, that the IDEAs of Descartes, and of his successors, were little else (at least so far as perception is concerned) than a new name for the species of the schoolmen;–the various ambiguities connected with the word idea, having probably contri
“ are impressions and ideas really extended, may ask his antagonists, how “they can incorporate a simple and indivisible subject with an extended “ perception.”—Treatise of Human Nature, Vol. 1. pp. 416,417.
buted not a little to shelter the doctrine, in its more modern dress, against those objections to which it must, at a much earlier Period, have appeared to be liable, if the old Peripatetic phraseology had been retained. The following passage from Hobbes, while it demonstrates the prevalence, at no very distant period, in its most absurd form, of the dogma which Reid has combated, may serve to illustrate, at the same time, the inefficacy of reason and common sense, when opposed to an established prejudice: “The Philosophy Schools, through all the Universities of “ Christendom, grounded upon certain texts of Aristotle, teach, “ that for the cause of vision, the thing seen sendeth forth, on “every side, a visible species (in English), a visible shew, appa“rition, or aspect, or a being seen; the receiving whereof into “ the eye is seeing. And for the cause of hearing, that the “ thing heard sendeth forth an audible species, that is, an audible “ aspect, or audible being seen; which entering at the ear, maketh “hearing. Nay, for the cause of understanding also, they say “ the thing understood sendeth forth an intelligible species, that “ is, an intelligible being seen; which, coming into the under“standing, makes us understand.”—“I say not this,” continues Hobbes, “as disapproving of the use of Universities, but because, “ as I am to speak hereafter of their office in a commonwealth, “I must let you see, on all occasions, by the way, what things “should be amended in them, amongst which, the frequency of in“significant speech is one.”—Of Man, Part I. Chap. i. About 150 years ago, when the dreams of the cloister were beginning to vanish before the dawning light of experimental science, the arguments which the schoolmen were obliged to have recourse to in their own defence, afford a commentary on the real import of their dogmas, which we should search for in vain in the publications of those ages, when they were regarded as oracles of truth, which it was the business of the philosopher not to dispute, but to unriddle. With this view, I shall extract a few remarks from a vindication of the Aristotelian doctrines, in opposition to some discourses of Sir Kenelm Digby, by an author of considerable celebrity among his contemporaries; but who is indebted chiefly for the small portion of fame which he now enjoys to a couplet of Hudibras. The aim of the reasonings which I am to quote is to shew, as the author himself informs us, that objects work not materially, but intentionally, on the sense ; and notwithstanding the buffoonery blended with them, they may be regarded as an authentic exposition of the scholastic opinion on this memorable question; a question which Alexander Ross appears to have studied as carefully, and as successfully, as any of the writers who have since undertaken the task of resolving it. “The atoms are your sanctuary to which you fly upon all oc
their doctrines are exhibited, is not only likely to draw a veil, impenetrable to most eyes, over many of the inconsistencies of though: which they may involve, but to give a dexterous advocate infinite advantages in defending and vindicating these inconsistencies, if they should be brought under discussion.—When, on the other hand, this technical language has been supplanted by a different phraseology, and when the particular dogmas which it was employed to support come to be examined in separate and unconnected detail, error and absurdity carry along with them the materials of their own refutation; and the mysterious garb, under which they formerly escaped detection, serves only to expose them to additional ridicule. Such has, in fact, been the case with the scholastic theory of perception, which, after maintaining its ground, without any dispute, during a succession of centuries, is now represented as an extravagance of too great a magnitude, to have been ever understood by its abettors in the literal sense which their words convey. It would be happy for science, if some of those who have lately expressed themselves in this manner, did not conceal from superficial readers, and probably from themselves also, under a different, but equally hypothetical form of words, the very same fundamental mistake which revolts their judgment so strongly, when presented to them in terms to which they have not been accustomed. The theory of Digby, too, when contrasted with that of his antagonist, is a historical document of considerable importance; exhibiting a specimen of the first attacks made on the system of the schoolmen, by the partisans of the new philosophy. The substitution of material images, instead of the ambiguous and mysterious species of Aristotle, by forcing the Peripatetics to speak out their meaning a little more explicitly, did more to bring them into dis
credit than the most acute and conclusive arguments of their op
ponents. Much about the same time, Dr Hooke expressed himself not less decidedly about the materiality of ideas or images ; employing a mode of speaking on this subject not very unlike that of Dr Darwin. Priestley's language is somewhat different from this, being faithfully modelled after the hypothesis of his master, Dr Hartley. “If,” says he, “as Hartley supposes, “ the nerves and brain be a vibrating substance, all sensations and “ideas are vibrations in that substance ; and all that is properly “ unknown in the business, is the power of the mind to perceive “ or be affected with these vibrations.” In what manner Dr Priestley would have reconciled this inference with what I have already quoted from him with respect to the idea of extension, I presume not to conjecture, As a further illustration of the notions which were prevalent with respect to the nature of sensible species, and that little more than a century ago, I shall quote a passage from a treatise, which,
notwithstanding its unpromising subject, was evidently the work
* In consequence of the growing influence of the Cartesian philosophy, these words were then beginning to be regarded as synonymous.