Representations whose subject and object depend immediately upon the ground and not upon any character of either. But the ground in any case must be a character of the representation which connects it with subject and object. Hence such representations are those which agree immediately with both subject and object in some characters. It is this sort of representation which an individual is of itself; and also which a sensation is. For a sensation agrees immediately with the thing in affecting the sense and with the mind in being affected by the thing. It is this sort of representation also which a picture is. Accordingly I call this species of representation copy.