CLASS IV. III. Intellectual at the same time that it conveys this information, produces such an additional effect, that the mind is able, at its own option, to call up an exact notion or idea of principle. those qualities at a distant period, or when the objects themselves are no longer present? Is there, or is there How atnot, any resemblance between the external or sensible tempted to be explained object, and the internal or mental idea or notion? If by former there be a resemblance, in what does that resemblance hypotheses. consist? and how is it produced and supported? Does Explanation the external object throw off representative likenesses of Epicurus. of itself in films or under any other modification, so fine as to be able, like the electric or magnetic aura, to pass without injury from the object to the sentient organ, and from the sentient organ to the sensory, or mental presence-chamber? or has the mind itself a Of Aristofaculty of producing, like a mirror, accurate countersigns, intellectual pictures or images correspondent with the sensible images communicated from the external object to the sentient organ? If, on the contrary, Of Plato there be no resemblance, are the mental perceptions mere notions, or intellectual symbols excited in the gists. mind by the action of the external sense; which, while they bear no similitude to the qualities of the object discerned, answer the purpose of those qualities, as letters answer the purpose of sounds? or are we sure Of Berkeley that there is any external world whatever; any thing and Hume. beyond the intellectual principle that perceives and the sensations and notions that are perceived; or even any thing beyond those sensations and notions, those impressions and ideas themselves? Several of these questions may perhaps appear in no small degree whimsical and brain-sick, and more worthy of St. Luke's than of a work of physiological study. But all of them, and at least as many more, of a temperament as wild as the wildest, have been asked and insisted upon, and supported again and again in different ages and countries, from the zenith of Grecian science down to our own day, by philosophers of the clearest intellects in other respects, and who had no idea of labouring tle. and later psycholo CLASS IV. under any such mental infirmity, nor ever dreamed of the necessity of being blistered and taking physic. III. Intel lectual principle. The obscurity of the subject proved by the nature of the questions proposed. The nature of the questions themselves, therefore, when put by the characters referred to, sufficiently manifest the obscurity of the subject to which they relate: and to enter into the discussions to which they have given rise, would lead us to an irrecoverable distance from the path before us. Those who are desirous of following them up and of witnessing an exposure of their These hy- absurdity, cannot do better than apply themselves to the metaphysical writings of Dr. Reid, Dr. Beattie, Dr. Campbell and Professor Stewart; who if, on the overthrow of so many Babel-buildings, they have not been able to raise an edifice much more substantial in their establishing stead, have only failed from the insuperable difficulty of the attempt. potheses thrown down by later writers who have little succeeded in any other. The difficulty felt by Locke, who studiously avoid ed the abstruser part of the No man was more sensible of this difficulty than Mr. Locke, nor has taken more pains both to avoid what is unintelligible and unprofitable, and to elucidate what may be turned to a good account and brought home to an ordinary comprehension. It was his imperishable Essay on Human Understanding that gave the first check to the wild and visionary conceits in which the most celebrated luminaries of the age were at that time engaged; recalled mankind from the chasing of shadows to the in his Essay study of realities, from a pursuit of useless and inexplicable subtleties to that of important and cognoscible subjects; or rather to the only mode in which the great inquiry before him could be followed up with any reasonable hope of success or advantage. subject, and elucidated what was capable of elucidation on Human Understanding. Character of this work. To this elaborate and wonderful work which has conferred an ever-during fame, not only on its matchless author, but on the nation to which he belonged, and even the age in which he lived, the physiologist cannot pay too close an attention. It is, indeed, of the highest importance to every science, as teaching us the elements of all science, and the only mode by which science can be rendered really useful, and carried forward to ultimate perfection; but it is of immediate importance to every branch CLASS IV. III. Intel lectual telligible of physical knowledge, and particularly to that which is employed in unfolding the structure of the mind, and its connexion with the visible fabric that incloses it. It may, principle. perhaps, be somewhat too long; it may occasionally embrace subjects which are not necessarily connected with it; its terms may not always be precise, nor its opinions in every instance correct: but it discovers intrinsic and most convincing evidence that the man who wrote it must have had a head peculiarly clear, and a heart peculiarly sound: it is strictly original in its matter, highly important in its subject, luminous and forcible in its argument, perspicuous in its style, and comprehensive in its scope. It steers equally clear of all former systems: we Avoids all have nothing of the mystical archetypes of Plato, the in- the unin corporeal phantasms of Aristotle, or the material species jargon of of Epicurus; we are equally without the intelligible times; world of the Greek schools, and the innate ideas of Des and clearly Cartes. Passing by all which, from actual experience and observation, it delineates the features, and describes the operations of the human mind with a degree of precision and minuteness which has never been exhibited either before or since; and stands, and probably ever will stand, like a rock before the puny waves of opposition by which it has since been assailed from various quarters. The author may speak of it with warmth, but he speaks from a digested knowledge of its merits: for he has studied it thoroughly and repeatedly, and there is, perhaps, no book to which he is so much indebted for whatever small degree of discrimination, or habit of reasoning he may possibly be allowed to lay claim to. former the growth developes and features of the mind from its earliest ap pearance. Has been misunder stood in some es sential points, Upon one point he is perfectly clear, and that is that the chief objections at any time urged against this celebrated production have proceeded from an utter mistake of its meaning, of which he could give numerous instances, if such a digression were allowable, from the writings of many who have the credit of having studied it profoundly. The remark applies to several of the most popular psychologists of both North and South Britain, but especially to those of the continent, and more parti- especially in France. CLASS IV. cularly still to M. Condorcet, from whom the French in III. Intel lectual principle. Gives to the medical student the physiology of the mind: as Haller and Hunter give that of the body. What the mind is when first formed. Powers or faculties of the mind compared with those of the body. Possibly a few slight produced before birth; and certainly instinctive general have received an erroneous idea of several of its leading doctrines. It is to this book the medical student ought to turn himself for a knowledge of the laws that regulate the developement and growth of the mind, as he should do to the labours of Haller or Hunter for a knowledge of those that regulate the developement and growth of the body, and I shall hence draw largely upon it through the remainder of this introduction. The whole then of the metaphysical rubbish of the ancient schools being cleared away by the purging and purifying energy of the Essay on Human Understanding, mankind have since been enabled to contemplate the body and mind as equally, at birth, a tabula rasa, or unwritten sheet of paper; as consisting equally of a blank or vacuity of impressions; but as equally capable of acquiring impressions by the operation of external objects, and equally and most skilfully endowed with distinct powers or faculties for this purpose; those of the body being the external senses of sight, hearing, smell, taste, and touch; and those of the mind the internal senses of perception, reason, judgement, imagination, and memory. It is possible that a few slight impressions may be proimpressions duced a short time antecedently to birth; and it is certain that various instinctive tendencies which, however, have no connection with the mind, are more perfect, because more needful, at the period of birth than ever afterwards; and we have also frequent proofs of an hereditary or accidental predisposition towards particular subjects. But the fundamental doctrine before us is by no means affected by such collateral circumstances. tendencies. First impression of external objects. External objects first impress or operate upon the outward senses; and these senses by means hitherto unexplained, and, perhaps, altogether inexplicable, immediately impress or operate upon the mind, or excite in it perceptions or ideas of the presence and qualities of such Idea, what, objects; the word idea being here employed, not in any of the significations of the schools, but in its broad, as em ployed by Locke. III. Intel popular meaning, as importing "whatever a man observes, CLASS IV. and is conscious to himself he has in his mind"*; what- lectual ever was formerly intended by the terms archetype, principle. phantasm, species, thought, notion, or conception, or whatever else it may be which we can be employed about sensation. in thinking. And to these effects Mr. Locke gave the Ideas of name of ideas of SENSATION, in allusion to the source from which they are derived. the mind on itself. But the mind, as we have already observed, has va- Action of rious powers or faculties as well as the body; and they are quite as active and lively in their respective functions: in consequence of which the ideas of external objects are not only perceived, but retained, thought of, compared compounded, abstracted, doubted, believed, desired; and hence another fountain, and of a very capacious flow, from which we also derive ideas: viz. a reflex act or perception of the mind's own operations; whence the ideas Ideas of derived from this fountain are denominated ideas of REFLEXION. reflexion. Ideas are therefore of two kinds, objective derived two sources. The ideas, then, derived from these two sources, and which have sometimes been called OBJECTIVE and SUBJECTIVE, constitute all our experience, and, consequently, and suball our knowledge. Whatever stock of information a man jective: may be possessed of, however richly he may be stored and only with taste, learning, or science, if he turn his attention from these inwards, and diligently examine his own thoughts, he will find that he has not a single idea in his mind, but what has been derived from the one or the other of these two channels. But let not this important observation be forgotten by any one; that the ideas the mind possesses will be fewer or more numerous, simpler or more diversified, clear or confused, according to the number of the objects presented to it, and the extent of its reflexion and examination. Thus a clock or a landscape may be for ever before our eyes, but unless we direct our attention to them, and study their different parts, although we cannot be deceived * Locke, on Human Understanding, B. 1. ch. i. § 3. + Locke, B. 1. ch. i. § 8. Number and nature of the ideas we possess, measured by the activity of the mind. |