be any one of these properties, there must necessarily be all.

136. Mental process in separating and abstracting them. The manner of expressing ourselves on the subject of our abstract notions, to which we have been accustomed, is apt to create and cherish a belief in the existence of a separate mental faculty, adapted solely to this particular purpose. But the doctrine of a power or faculty of abstraction, which is exclusive of other mental susceptibilities, and is employed solely for this purpose, does not appear to be well founded. It will convey an impression nearer the truth to speak of the PROCESS rather than the power of abstraction.-The following statement will be sufficient to show how those of the first class, or particular abstract ideas, are formed.

Although our earliest notions, whether they arise from the senses or are of an internal origin, are simple, existing in an independent and separate state, yet those simple thoughts are very soon found to unite together with a considerable degree of permanency, and out of them are formed complex states of mind. Many are in this way combined together in one, and the question is, how this combination is to be loosened, and the elementary parts are to be extracted from their present complexity?

In answer it may be said, that in every case of separating a particular abstract idea, there must necessarily be a determination, a choice, an act of the will. This voluntary state of mind must concern the previous complex mental state, when viewed in one respect rather than another; or, what is the same thing, it will concern one part of the complex idea rather than another. So that we may truly and justly be said to have not only a desire, but a determination to consider or examine some part of the complex idea more particularly than the others. When the mind is in this manner directed to any particular part of a complex notion, we find it to be the fact, that the principle of association, or whatever principle it is, which keeps the other parts in their state of union with it, ceases in a greater or less degree to operate and to maintain that union; the other parts rapidly

fall off and disappear, and the particular quality, towards which the mind is particularly directed, remains the sole subject of consideration. That is to say, it is abstracted or becomes an abstract idea.-If, for example, we have in mind the complex notion of any object, a house, tree, plant, flower, and the like, but have a desire and determination to make the colour, which forms a part of this complex notion, a particular subject of attention, the consequence is, that, while the quality of colour occupies our chief regard, the other qualities will disappear and no more be thought of. If we determine to examine the weight or extension of an object, the result will be the same; in other words, the extension, weight, colour, &c., becoming distinct and exclusive objects of attention, will be abstracted.

This, in the formation of particular abstract ideas, seems to be the process of the mind, and nothing more, viz. The direction of an act of the will to a particular part of a complex notion, and the consequent detention of the part towards which the mental choice is directed, and the natural and necessary disappearance, under such circumstances, of the other parts.

§ 137. Of generalizations of particular abstract mental states. The terms GENERALIZING and GENERALIZATION are often found applied to the states of mind under consideration. When we have made any quality of a body a distinct and separate subject of attention, we may further regard it as belonging to one or more objects, according as we find such to be the fact or otherwise. What is chiefly meant, therefore, when we speak of the generalizing of this class of abstract notions, is, that, in our experience of things, we observe them to be common to many subjects. We find whiteness to be a quality of snow, of chalk, of inilk, and of other bodies; and whenever, with the sim ple abstract notion of whiteness, we connect in our thoughts the additional circumstance of its not being limited to one body, but the property of many, the term may be said to be generalized. And this seems to be all that can be properly understood by generalization when applied to the states of mind now before us.

138. Of the importance and uses of abstraction. The power of Abstraction, as it has sometimes been called, is by no means an unimportant one, even when limited to the separation of the particular or simple elements of thought.-" A carpenter," says Kames,* speaking of the great utility of abstraction," considers a log of wood with regard to hardness, firmness, colour, and texture; a philosopher, neglecting these properties, makes the log undergo a chemical analysis, and examines its taste, its smell, and component principles; the geometrician confines his reasoning to the figure, the length, breadth, and thickness; in general, every artist, abstracting from all other properties, confines his observations to those which have a more immediate connexion with his profession."

Besides its well-known uses in the various forms of reasoning (particularly demonstrative reasoning), abstraction is greatly subservient to the exertions of a creative imagination, as they appear in painting, architecture, poetry, and the other fine or liberal arts.-The poet and the painter are supplied with their materials from experience; without having received ideas from some source, they never could have practised their art. But, if they do not restrict themselves to mere imitation, they must combine and modify the ideas which they have, so as to be able to form new creations of their own. But. every such exertion of their powers presupposes the exercise of abstraction in decomposing and separating actual conceptions, and in forming them anew. The power of abstraction, therefore, may justly be considered as a characteristic of the great masters in the liberal arts. From how many delightful forms in nature, and how many ideal temples, contemplated for a long time in the mind's eye, must the genius that planned the Parthenon have abstracted each form of beauty and excellence of proportion! From how many forests, both seen and imagined, and fields of bloom, and rivers and waterfalls, must the mind that conceived the Garden of Paradise Lost have drawn the sounds that delight the ear, and the colours that are pleasant to the sight!

* Elements of Criticism, vol. iii., Appendix.

CHAPTER XIII.

GENERAL ABSTRACT IDEAS.

139. General abstract notions the same with genera and species. WE proceed, in connexion with the remarks of the last chapter, to the consideration of GENERAL ABSTRACT ideas; a subject of no little interest, and which has frequently been thought to be attended with no small difficulty.

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General Abstract notions are not only different, in consequence of embracing a greater number of elementary parts, from those which are particular, but are also susceptible of being distinguished from the great body of our other complex notions.-The idea, for example, which we form of any individual, of John, Peter, or James, is idently a complex one, but it is not necessarily a general one. The notion which we frame, of a particular horse or of a particular tree, is likewise a complex idea, but not a general one. There will be found to be a clear distinction between them, although it may not be perfectly obvious at first. GENERAL ABSTRACT IDEAS are our notions of the classes of objects, that is, of Genera and Species. They are expressed by general names, without, in most cases, any defining or limitation, as when we use the words ANIMAL, MAN, HORSE, bird, sheep, fish, TREE, not to express any one in particular of these various classes, but animals, men, horses, &c., in general.

140. Process in classification, or the forming of genera and species. Now if our general abstract ideas, as far as they relate to external objects, are truly notions of SPECIES and GENERA, it will aid us in the better understanding of them if we briefly consider how species and genera are formed. Men certainly find no great practical difficulty in forming these classifications, since we find that they do in fact make them in numberless instances, and at a very early period of life. They seem to be governed in the process

by definite and uniform mental tendencies.-What, then, in point of fact, is the process in classification? It is obvious, in the first place, that no classification can be made without considering two or more objects together. A number of objects, therefore, are first presented to us for our observation and inquiry, which are to be examined first in themselves, and then in comparison with each other. We will take a familiar scene to illustrate what takes place.

We suppose ourselves to stand on the bank of a navıgable river; we behold the flowing of its waters, the cliffs that overhang it, the trees that line its shore, the boats and boatmen on its bosom, the flocks and herds that press down to drink from its waves. With such a scene before us, it is to be expected that the mind will rapidly make each and all of these the subjects of its contemplation; nor does it pursue this contemplation and inquiry far, without perceiving certain relations of agreement or difference. Certain objects before it are felt to be essentially alike, and others to be essentially different; and hence they are not all arranged in one class, but a discrimination is made, and different classes are formed. The flocks and herds are formed into their respective classes. The tall and leafy bodies on the river's bank, although they differ from each other in some respects, are yet found to agree in so many others, that they are arranged together in another class, and called by the general name of TREE. The living, moving, and reasoning beings, that propel the boats on its waters, form another class, and are called MAN.-And there is the same process, and the same result, in respect to all other bodies coming within the range of our observation.

141. Early classifications sometimes incorrect.

It has been intimated, that, in making these classifications, men are governed by definite and uniform mental tendencies; still it must be acknowledged that mistakes are sometimes committed, especially in the early periods of society, and in all cases where the opportunities of examination and comparison are imperfect. When man first opens his eyes on nature (and in the infancy of our