§ II.—Province and Relation of several Terms employed to denote, in Part, or as a Whole, this Power of the Mind.
We are now prepared to consider the proper province and relation of several terms frequently employed, with considerable latitude and diversity of meaning, to denote, in part, or as a whole, the process now described. Such are the terms abstraction, generalization, classification, and judgment.
I. Abstraction.
Term often used in a Wide Sense.—This term is frequently employed to denote the entire synthetic process as now described—the power of forming abstract general conceptions, and of classifying objects according to those conceptions. It is thus employed by Stewart, Wayland, Mahan, and others. There is, perhaps, no objection to this use of the word, except that it is manifestly a departure from the strict and proper sense of the term.
More limited Sense.—There is another and more common use of the term abstraction, which gives it a more limited sense. As thus employed, it denotes that act of the mind by which we fix our attention on some one of the several parts, properties, or qualities of an object, to the exclusion of all the other parts or properties which go to make up the complex whole. In consequence of this exclusive direction of the thoughts to that one element, the other elements or properties are lost sight of, drop out of the account, and there remains in our present conception only that one item which we have singled out from the rest. This is denominated, in common language, abstraction. Such is the common idea and definition of that term. It is Mr. Upham's definition.
This not really Abstraction.—Whether this, again, is the true idea of abstraction, is, to say the least, questionable. When I think of the cover of a book, the handle of a door, the spring of a watch, in distinction from the other parts which make up a complex whole, I am hardly exercising the power of abstract thought; certainly no new, distinct faculty is requisite for this, but simply attention to one among several items or objects of perception. Hardly ever can it be called analysis, with Wayland. It is the simple direction of the thought to some one out of several objects presented. A red rose is before me. I may think of its color exclusively, in distinction from its form and fragrance; that is, of the redness of this particular rose, this given surface before me. The object of my thought is purely a sensible object. I have not abstracted it from the sensible individual object to which it belongs. It is in no sense an abstract idea, a pure conception. There has been nothing done which is not done in any case where one thing, rather than another of a group or assemblage of objects, is made the object of attention.
The true Nature of Abstraction.—But suppose now that instead of thinking of the redness of this rose in particular, I think of the color red in general, without reference to the rose or any other substance; or, to carry the process further, of color in general, without specifying in my thought any particular color, evidently I am dealing now with abstractions. I have in my thought drawn away (abstraho) the color from the substance to which it belongs, from all substance, and it stands forth by itself a pure conception, an abstraction, having, as such, no existence save in my mind, but there it does exist a definite object of contemplation. The form of mental activity now described, I should call abstraction. It is not necessary, perhaps, to assign it a place as a distinct faculty of the mind. It is, in reality, a part, and an important part, of the synthetic process already described. But it is not the whole of that process, and the term abstraction should not, therefore, in strict propriety, at least as now defined, be applied as a general term to designate that class of mental operations. The synthetic process involves something more than mere abstraction; viz.:
II. Classification As Distinguished From Generalization.
Classification.—When the general idea or conception has been formed in the mind, we proceed to bring together and arrange, on the basis of that general conception, whatever individual objects seem to us to fall under that general rule. This we call classification. Thus, forming first the abstract, or general conception red, we bring together in our thought a variety of objects to which this conception is applicable, as red horses, red flowers, red books, red tables, etc., etc., thus forming classes of objects on the ground of this common property. The difference between classification and generalization, in so far as they are not synonymous, I take to be simply this, that in the former we group and arrange objects according to no general law, but mere appearance or resemblance, often, therefore, on fanciful or arbitrary grounds while in the latter case, we proceed according to some general and scientific principle or law of classification, making only those distinctions the basis of our arrangement which are founded in nature, and are at once invariable and essential.