The subjective ghosts are legion in modern fiction. They are those evoked by the mental state of the percipients so that they become realities to those beholding them. The mind rendered morbid by grief or remorse is readily prepared to see the spirits of the dead return in love or with reproach. The apparitions in animistic beliefs, as in classical stories and Gothic romance, were usually subjective, born of brooding love or remorse or fear of retribution, appearing to the persons who had cause to expect them and coming usually at night when the beholders would be alone and given over to melancholy thought or else to troubled sleep. Shakespeare's ghosts were in large measure subjective, "selective apparitions." When Brutus asked the specter what he was, the awful answer came, "Thy evil genius, Brutus!" Macbeth saw the witches who embodied for him his own secret ambitions, and he alone saw the ghost of Banquo, because he had the weight of murder on his heart. The subjective ghost story is difficult to write, as the effect must be subtly managed yet inescapably impressive. If done well it is admirable, and there are some writers who, to use Henry James's words concerning his own work, are "more interested in situations obscure and subject to interpretation than the gross rattle of the foreground." The reader, as well as the writer, must put himself in the mental attitude of acceptance of the supernatural else the effect is lacking, for the ghostly thrill is incommunicable to those beyond the pale of at least temporary credulity.