(_a_) In range and variety of form it is impossible to exhaust the resources of metaphor; its definition, however, is simple. It is a wholly abbreviated comparison, in which we find, as a fact, image and significance are not as yet set in opposition to one another, but only the image is introduced by it; at the same time, however, the meaning which is thus attached to the image is not its real meaning; this is as it were effaced, and by virtue of the content in which it is set we are enabled to recognize the significance which is really intended in the image itself, albeit that meaning is not expressly asserted. For the reason, however, that the meaning that is thus rendered intelligible under the image only comes to light by virtue of the context, the significance which is expressed in metaphor cannot claim the importance of an independent artistic presentation; their mode of appearance is purely incidental, so that metaphors, in a still more emphatic degree, can only be employed as the external embellishment of an essentially independent work of art. (_β_) The metaphor is mainly used in the expressions of speech, which we may usefully consider in this relation under the following aspects. (_αα_) In the first place every language includes within its own compass a host of metaphors. They arise from the fact that a word, which in the first instance merely designates something entirely sensuous, is carried over into a spiritual sphere. "_Grasp"_, "_comprehend"_[92], and generally a number of words connected with the processes of thought, have in regard to their original meaning a content that is wholly sensuous, which is consequently abandoned and exchanged for the meaning applicable to mind; the first meaning is sensuous, the second spiritual. (_ββ_) By degrees, however, the metaphorical aspect disappears in the general use of such a word, which as the current coin of language is converted from an expression which is not strictly accurate to one that is so, the effect of this process being that image and import, owing to the habitual frequency with which the latter is only conceived in the former, cease to differ from one another, and the image merely immediately presents the abstract significance itself instead of a concrete mode of vision[93].