“ignorance could ever make so strange a mistake, there "not being the most distant similitude between a sheep or "a goat, and any winged animal. But these people seemed "to know nothing of the existence of any other land ani"mals, besides hogs, dogs, and birds. Our sheep and goats, "they could see, were very different creatures from the "two first, and therefore they inferred that they must be"long 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 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 num ber 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 ground-work of classifi cation, 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. 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.

And it

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 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 sep: arately, 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 the lines in the diagrams are really extended in two dimensions, yet that the demonstrations relate only to one of them; and that the human understanding has the faculty of reasoning concerning things separately, which are always presented to us, both by our powers of percep tion and conception, in a state of union. Such abstractions, in truth, are familiar to the most illiterate of mankind; and it is in this very way that they are insensibly formed. When a tradesman speaks of the length of a room, in contradistinction to its breadth; or when he speaks of the

distance between any two objects, he forms exactly the same abstraction, which is referred to by Euclid in his second definition; and which most of his commentators have thought it necessary to illustrate by prolix metaphysical disquisitions.

I shall only observe farther, with respect to the nature and province of this faculty of the mind, that notwithstanding its essential subserviency to every act of classification, yet it might have been exercised, although we had only been acquainted with one individual object. Although, for example, we had never seen but one rose, we might still have been able to attend to its colour, without thinking of its other properties. This has led some philosophers to suppose, that another faculty besides abstraction, to which they have given the name of generalization, is necessary to account for the formation of genera and species; and they have endeavoured to shew, that although generalization without abstraction is impossible; yet that we might have been so formed, as to he able to abstract, without being capable of generalizing. The grounds of this opinion, it is not necessary for me to examine, for any of the purposes which I have at present in view.

SECTION II.

Of the Objects of our Thoughts, when we employ general Terms.

FROM the account which was given in a former chapter, of the common theories of perception, it appears to have been a prevailing opinion among philosophers, that the qualities of external objects are perceived, by means of images or species transmitted to the mind by the organs of sense: an opinion of which I already endeavoured to trace the origin, from certain natural prejudices suggested