Erroneous interpretation of Freud has occurred because psychologist-historians use common sense to test their theories and do not consult relevant documents. Eissler advocates the principle of "unrestricted exegesis" moving into "psychoanalytic common sense," i.e., a set of working hypotheses held in common by psychoanalysts. An analogy is examined and preconscious or unconscious imagery is reconstructed. Content may be interpreted in all possible directions: literal, literary, personal, historical, and symbolic. It "may be looked at as a day residue, as a derivative of a repressed impulse, as a biographical element, as a referent to a historical event, or as if it were part of a legend, fairy tale, or as an archaic symbol derived from any area of culture, religion, art, and so on." Eissler cautions, however, of the danger of overinterpretation.