No activity is thus aroused and directed towards the object, in order to recognize its qualities in such a manner that the child himself forms an idea of it; nor can the possibility of connecting other objects with the first by their common characteristics arise in his mind. For in what particular does any object resemble the others? In its use? When we associate the images of different objects by similarity, we should extract from the whole the qualities which the objects themselves have in common. If, for instance, we say that two rectangular tablets are alike, we have first extracted from the numerous qualities of these tablets such facts as that they are of wood, that they are polished, smooth, colored, of the same temperature, etc., the quality relating to their _shape_. They are alike in _shape_. This may suggest a long series of objects: the top of the table, the window, etc.; but before such a result as this can be achieved, it is necessary that the mind should first be capable of abstracting from the numerous attributes of these objects the quality of _rectangular shape_. The work of the mind in this quest must necessarily be _active_; it analyzes the object, extracts a determined attribute therefrom, and under the guidance of this determined attribute makes a synthesis associating many objects by the same medium of connection. If this capacity for the selecting of single attributes among all those proper to the object be not acquired, association by means of similarity, synthesis, and all the higher work of the intelligence becomes impossible. Moreover, this is intellectual work in reality, because the essential quality of the intelligence is not to "photograph" objects, and "keep them one upon the other" like the pages of an album, or juxtaposed like the stones in a pavement. Such a labor of mere "deposit" is an outrage on the intellectual nature. The intelligence, with its characteristic orderliness and power of discrimination, is capable of distinguishing and extracting the dominant characteristics of objects, and it is upon these that it proceeds to build up its internal structures.