Note 16 — Chapter II

Hence, the only valid distinction that can be drawn between abstraction and generalization is that which has been drawn by Hamilton, as follows: “Abstraction consists in concentration of attention upon a particular object, or particular quality of an object, and diversion of it from everything else. The notion of the figure of the desk before me is an abstract idea—an idea that makes part of the total notion of that body, and on which I have concentrated my attention, in order to consider it exclusively. This idea is abstract, but it is at the same time individual: it represents the figure of this particular desk, and not the figure of any other body.” Generalization, on the other hand, consists in an ideal compounding of abstractions, “when, comparing a number of objects, we seize on their resemblances; when we concentrate our attention on these points of similarity.... The general notion is thus one which makes us know a quality, property, power, notion, relation, in short, any point of view under which we recognize a plurality of objects as a unity.” Thus, there may be abstraction without generalization; but inasmuch as abstraction has then to do only with particulars, this phase of it is disregarded by most writers on psychology, who therefore employ abstraction and generalization as convertible terms. Mill says, “By abstract I shall always, in Logic proper, mean the opposite of concrete; by an abstract name the name of an attribute; by a concrete name, the name of an object” (Logic, i. § 4). Such limitation, however, is arbitrary—it being the same kind of mental act to “concentrate attention upon a particular object,” as it is to do so upon any “particular quality of an object.” Of course in this usage Mill is following the schoolmen, and he expressly objects to the change first introduced (apparently) by Locke, and since generally adopted. But it is of little consequence in which of the two senses now explained a writer chooses to employ the word “abstract,” provided he is consistent in his own usage.