The cynical Dr. Relling is Hialmar's longtime antagonist from the Hoidal works and his rival over the fate of Hialmar. Appearing as a figure of critical knowledge, he in some sense incarnates Ibsen's famous turn to the psychological. Relling pits himself against Gregers's appeals to the ideal as all so much "quakery." Rather than engage with Gregers on his own terms—"spiritual tumults" and a Christian logic of forgiveness and redemption—Relling recasts their discussion in a quasi-medical discourse of pathology. Thus Relling considers the ideal as little more than a lie: the two are related as typhus is to putrid fever. Man does not require redemption but treatment, an inoculation he terms the "life-illusion" or "life-lie." The life-lie, be it the delusions of Ekdal in his garret or Molvik's conviction that he is possessed, makes the patient's survival possible, guarding against his complete disintegration.

Relling above all offers diagnosis, evaluating the pathologies of both the play's romantic protagonists. In his eyes, Hialmar has too long figured as the "shining light" within his private circles; he has done so since in the care of his "hysterical" spinster aunts. Gregers suffers from an "integrity-fever" in his guilt over the Ekdals' ruin and a "delirium of hero-worship." With such diagnoses, Relling would replace metaphysics with metapsychology.