sity of extent, are not objects of sense, but of conception; and the notions we form of them when our eyes are open, differ from those we should form of them with our eyes shut, only in this, that they are kept steadily in the view of the mind, by being strongly associated with the sensations of colour, and with the original perceptions of sight. This observation will be the more readily admitted, if it be considered, that, by a skilful imitation of a natural landscape in a common shew-box, the mind may be led to form the same notions of variety of distance, and even of immense extent, as if the original scene were presented to our senses: and that, although, in this case, we have a speculative conviction that the sphere of our vision only extends to a few inches, yet so strong, is the association between the original perceptions of sight, and the conceptions which they habitually produce, that it is not possible for us, by any effort of our will, to prevent these conceptions from taking place.

From these observations it appears, that when the conceptions of the mind are rendered steady and permanent, by being strongly associated with any sensible impression, they command our belief no less than our actual perceptions; and, therefore, if it were possible for us, with our eyes shut, to keep up, for a length of time, the conception of any sensible object, we should, as long as this effort continued, believe that the object was present to our senses.

It appears to me to be no slight confirmation of these remarks, that although, in the dark, the illusions of imagination are much more liable to be mistaken for realities, than when their momentary effects on the belief are continually checked and corrected by the objects which the light of day presents to our perception, yet, even total darkness is not so alarming to a person impressed with the vulgar stories of apparitions, as a faint and doubtful twilight, which affords to the conceptions an opportunity of fixing and prolonging their existence, by attaching themselves to something which is obscurely exhibited to the eye.-In like manner, when we look through a fog, we are frequently apt to mistake a crow for a man; and the conception we have, upon such an occasion, of the human figure, is much more distinct and much more steady, than it would be possible for us to form, if we had no sensible object before us; in so much that when, on a more attentive observation, the crow shrinks to its own dimensions, we find it impossible, by any effort, to conjure up the phantom which a moment before we seemed to perceive.

If these observations are admitted, the effects which exhibitions of fictitious distress produce on the mind, will appear less wonderful than they are supposed to be. During the representation of a tragedy, I acknowledge, that we have a general conviction that the whole is a fiction, but, I believe, it will be found, that the violent emotions which are sometimes produced by the distresses of the stage, take their rise, in most cases, from a momentary belief, that the distresses are real. I say, in most cases, because I acknowledge, that independently of any such belief, there is something contagious in a faithful expression of any of the passions.

The emotions produced by a tragedy are, upon this supposition, somewhat analogous to the dread we feel when we look down from the battlement of a tower.* In both cases, we have a general conviction, that there is no ground for the feelings we experience, but the momentary influences of imagination are so powerful as to produce these feelings, before reflection has time to come to our relief.

CHAPTER FOURTH.

OF ABSTRACTION.

SECTION I.

THE

General observations on this Faculty of the Mind.

HE origin of appellatives, or, in other words, the origin of those classes of objects which, in the schools, are called genera, and species, has been considered by some philosophers as one of the most difficult problems in metaphysics. The account of it which is given by Mr. Smith, in his Dissertation on the Origin of Languages, appears to me to be equally simple and satisfactory.

"The assignation" (says he)" of particular names, to denote par"ticular objects; that is, the institution of nouns substantive, would "probably be one of the first steps towards the formation of Lan"guage. The particular cave, whose covering sheltered the savage from the weather; the particular tree, whose fruit relieved "his hunger; the particular fountain, whose water allayed his "thirst; would first be denominated by the words, cave, tree, foun"tain; or by whatever other appellations he might think proper, " in that primitive jargon, to mark them. Afterwards, when the

With respect to the dread which we feel in looking down from the battlement of a tower, it is curious to remark the effects of habit in gradually destroying it. The manner in which habit operates in this case, seems to be by giving us a command over our thoughts, so as to enable us to withdraw our attention from the precipice before us, and direct it to any other object at pleasure. It is thus that the mason and the sailor not only can take precautions for their own safety, but remain completely masters of themselves in situations where other men, engrossed with their imaginary danger, would expe rience a total suspension of their faculties. Any strong passion, which occupies the mind, produces, for the moment, the same effect with habit. A person alarmed with the apprehension of fire, has been known to escape from the top of a house, by a path which, at another time, he would have considered as impracticable; and soldiers, in mounting a breach, are said to have sometimes found their way to the enemy, by a route which appeared inaccessible after their violent passions had subsided.

"more enlarged experience of this savage had led him to observe, "and his necessary occasions obliged him to make mention of, other 66 caves, and other trees, and other fountains; he would naturally "bestow upon each other of those new objects, the same name by "which he had been accustomed to express the similar object he was first acquainted with. And thus, those words, which were "originally the proper names of individuals, would each of them in66 sensibly become the common name of a multitude."*

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"It is this application" (he continues)" of the name of an indi"vidual to a great number of objects, whose resemblance naturally "recalls the idea of that individual, and of the name which ex"presses it, that seems originally to have given occasion to the for"mation of those classes, and assortments, which, in the schools, are "called genera, and species; and of which the ingenious and elo"quent Rousseau finds himself so much at a loss to account for the "origin. What constitutes a species, is merely a number of objects, "bearing a certain degree of resemblance to one another; and, on "that account, denominated by a single appellation, which may be "applied to express any one of them."t

This view of the natural progress of the mind, in forming classifications of external objects, receives some illustration from a fact mentioned by Captain Cook in his account of a small island called Wateeoo, which he visited in sailing from New Zealand to the Friendly Islands. "The inhabitants," says he, "were afraid to come "near our cows and horses, nor did they form the least conception "of their nature. But the sheep and goats did not surpass the lim"its of their ideas; for they gave us to understand that they knew "them to be birds. It will appear," he adds, "rather incredible, "that human ignorance could ever make so strange a mistake, there "not being the most distant similitude between a sheep or goat, "and any winged animal. But these people seemed to know nothing of the existence of any other land animals, besides hogs, dogs, "and birds. Our sheep and goats, they could see, were very diffe"rent creatures from the two first, and therefore they inferred that "they must belong to the latter class, in which they knew that there "is a considerable variety of species."-I would add to Cook's very judicious remarks, that the mistake of these islanders probably did not arise from their considering a sheep or a goat as bearing a more striking resemblance to a bird, than to the two classes of quadrupeds with which they were acquainted; but to the want of a generic word, such as quadruped comprehending these two species; which

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The same account of the progress of the mind in the formation of genera, is given by the Abbé de Condillac.

Un

"Un enfant appelle du nom d'Arbre le premier arbre que nous lui montrons. second arbre qu'il voit ensuite lui rapelle la même idée; il lui donne le même nom; de même à un troisième, à un quatrième, et voilà le mot d'Arbre douné d'abord à un individu, qui devient pour lui un nom de classe ou de genre, une ideé abstraite qui comprend tous les arbres en général.

+ Dissertation on the Origin of Languages, annexed to Mr. Smith's Theory of Mora! Sentiments. Boston edition, vol. ii. p. 217, &c.

men in their situation would no more be led to form, than a person who had only seen one individual of each species, would think of an appellative to express both, instead of applying a proper name to each. In consequence of the variety of birds, it appears, that they had a generic name comprehending all of them, to which it was not unnatural for them to refer any new animal they met with.

The classification of different objects supposes a power of attending to some of their qualities or attributes, without attending to the rest; for no two objects are to be found without some specific difference; and no assortment or arrangement can be formed among things not perfectly alike, but by losing sight of their distinguishing peculiarities, and limiting the attention to those attributes which belong to them in common. Indeed, without this power of attending separately to things which our senses present to us in a state of union, we never could have had any idea of number; for, before we can consider different objects as forming a multitude, it is necessary that we should be able to apply to all of them one common name; or, in other words, that we should reduce them all to the same genus. The various objects, for example, animate and inanimate, which are, at this moment, before me, I may class and number in a variety of different ways, according to the view of them that I choose to take. I may reckon successively the number of sheep, of cows, of horses, of elms, of oaks, of beeches; or I may first reckon the number of animals, and then the number of trees; or I may at once reckon the number of all the organized substances which my senses present to me. But whatever be the principle on which my classification proceeds, it is evident, that the objects numbered together, must be considered in those respects only in which they agree with each other; and that, if I had no power of separating the combinations of sense, I never could have conceived them as forming a plurality.

This power of considering certain qualities or attributes of an object apart from the rest; or, as I would rather choose to define it, the power which the understanding has, of separating the combinations which are presented to it, is distinguished by logicians by the name of abstraction. It has been supposed by some philosophers, (with what probability I shall not now inquire,) to form the characteristical attribute of a rational nature. That it is one of the most important of all our faculties, and very intimately connected with the exercise of our reasoning powers, is beyond dispute. And, I flatter myself, it will appear from the sequel of this chapter, how much the proper management of it conduces to the success of our philosophical pursuits, and of our general conduct in life.

The subserviency of Abstraction to the power of Reasoning, and also, its subserviency to the exertions of a Poetical or Creative Imagination, shall be afterwards fully illustrated. At present, it is sufficient for my purpose to remark, that as abstraction is the groundwork of classification, without this faculty of the mind we should have been perfectly incapable of general speculation, and all our

knowledge must necessarily have been limited to individuals; and that some of the most useful branches of science, particularly the different branches of mathematics, in which the very subjects of our reasoning are abstractions of the understanding, could never have possibly had an existence. With respect to the subserviency of this faculty to poetical imagination, it is no less obvious, that, as the poet is supplied with all his materials by experience; and as his province is limited to combine and modify things which really exist, so as to produce new wholes of his own; so every exertion which he thus makes of his powers, presupposes the exercise of abstraction in decomposing and separating actual combinations. And it was on this account, that, in the chapter on Conception, I was led to make a distinction between that faculty, which is evidently simple and uncompounded, and the power of Imagination, which (at least in the sense in which I employ the word in these inquiries) is the result of a combination of various other powers.

I have introduced these remarks, in order to point out a difference between the abstractions which are subservient to reasoning, and those which are subservient to imagination. And, if I am not mistaken, it is a distinction which has not been sufficiently attended to by some writers of eminence. In every instance in which imagination is employed in forming new wholes, by decompounding and combining the perceptions of sense, it is evidently necessary that the poet or the painter should be able to state to himself the circumstances abstracted, as separate objects of conception. But this is by no means requisite in every case in which abstraction is subservient to the power of reasoning; for it frequently happens, that we can reason concerning one quality or property of an object abstracted from the rest, while, at the same time, we find it is impossible to conceive it separately. Thus, I can reason concerning extension and figure, without any reference to colour; although it may be doubted, if a person possessed of sight can make extension and figure steady objects of conception, without connecting with them. one colour or another. Nor is this always owing (as it is in the instance now mentioned) merely to the association of ideas; for there are cases, in which we can reason concerning things separately, which it is impossible for us to suppose any being so constituted as to conceive apart. Thus, we can reason concerning length, abstracted from any other dimension; although, surely, no understanding can make length, without breadth, an object of conception. And by the way, this leads me to take notice of an errour, which mathematical teachers are apt to commit, in explaining the first principles of geometry. By dwelling long on Euclid's first definitions, they lead the student to suppose that they relate to notions which are extremely mysterious, and to strain his powers in fruitless attempts to conceive, what cannot possibly be made an object of conception. If these definitions were omitted, or very slightly touched upon, and the attention at once directed to geometrical reasonings, the student would immediately perceive, that although