An adroitly interpolated motif in A Doll's House concerns Helmer's friend, Dr. Rank, whose incurable disease a retribution for his father's gay life illustrates Ibsen's two converging ideas of fate. Belonging to an age in which the importance of the law of heredity was paramount, Ibsen worked out in Ghosts the moral and the biological conceptions of fate as forcefully as he could. The impression of Ghosts, with its overhanging atmosphere of fate, can be tremendous. Even those who are inclined to accuse Ibsen of sensationalism cannot but admit that here a very risky theme has been handled with the greatest artistic tact. In June 1882 Ibsen confided in a letter to the Norwegian author Jonas Lie that he was not yet sure whether to call this work a comedy or a drama, since 'it partakes of the nature of either, or lies half-way between'.