A serious critic has to comprehend the particular content, unique  structure, and  special meaning of a work of art. And here she faces a dilemma. The critic must recognize the artistic element of uniqueness that requires subjective reaction; yet she must not be unduly prejudiced by such reactions. Her likes and dislikes are less important than what the work itself communicates, and her preferences may blind her to certain qualities of the work and thereby prevent an adequate understanding of it. Hence. it is necessary that a critic develop a sensibility informed by familiarity with the history of an and aesthetic theory On the other hand, it is insufficient to treat the artwork solely historically ,in relation to a fixed set of  ideas or values. The critics knowledge and training are , rather a preparation of the cognitive and emotional abilities needed an adequate personal response to an artworks  own particular qualities.  which one is not a factor in understanding a particular an work for criticism?