Abstract, abstraction. None of the objects presented to us by perception are simple. Even the least complicated are combined of various qualities; and in order to attain a distinct notion of any of these, it is needful to separate it in thought from the rest of the combination in which it presents itself. The process whereby this is done is called abstraction, a drawing off; and that which is thus drawn off from the elements with which it is surrounded is said to be viewed abstractedly, or in the abstract.
Similarly, nothing is ever seen by us in the mere aspect of its definition, but always with attendant accidents which do not enter into that definition, and occur some in one object that comes under it, some in another. When therefore we withdraw our attention from these, and fix it simply on the definition, we perform an act of abstraction.
The opposite to the abstract is the concrete (from the participle passive of concrescere, to grow together with). It is in the concrete that all objects are perceived by us. Their definition or some of their qualities when taken by themselves are not perceived but thought.
The process of abstraction is a necessary antecedent to that of generalization. The concrete presentation cannot be an universal, and only by abstracting that which such presentation has in common with others can we arrive at one.
It has been questioned whether language be not a necessary condition of abstraction, and therefore whether the infant before acquiring that, and the lower animals who never do, are capable of the process. Undoubtedly, language by supplying us with names for abstractions is a great aid in the formation of such, nor could we exercise the faculty to any great extent without it. But on the other hand the faculty seems a needful preliminary to the formation of abstract words. It is likely that in this matter, as in the case of so many elements of our mental being, the two act and re-act on each other. Without the faculty of abstraction we could make no abstract terms; and without abstract terms, the faculty of abstraction would be little developed.
Whether it be true that the lower animals are incapable of abstraction is a question not easily decided. In the gradual inspection and then complete recognition of an old friend from whom he has long been separated, the dog seems to arrive at a synthesis of marks and attributes, each of which he must have considered in the abstract. What I should be inclined to say is that he abstracts but little, and scarcely generalizes, if he does the latter at all.
The principal sciences which deal with abstractions are mathematics and logic. These in their pure form are wholly abstract. So too is their symbolic notation. But all science as such demands abstraction, without which there could be no generalization. The naturalist no doubt examines a specimen of concrete existence, but his aim is to arrive at the definition under which it comes, and the class to which it belongs, and this can only be done by separating essential characteristics from the accidents with which they are accompanied.
