Suddenly Mrs. Sorby appears at the door. She has come to bid farewell to Gina as she and Werle are moving to the Hoidal works tomorrow. Gregers reveals their marriage plans. Relling bitterly wishes her happiness. Apparently Relling and Sorby once shared a liaison. When Gregers threatens to tell his father of their affair, Mrs. Sorby informs him that they have confessed all their secrets to each other and theirs is an honest marriage.
Sorby has pledged to care for Werle in his increasing blindness. Hialmar is shocked that Werle is losing his eyesight too. As she moves to leave, Sorby instructs Hialmar to apply to Graberg if he needs anything. Shocking even Gregers, Hialmar not only declines this offer of help but promises to pay back their longstanding debt to the firm—a debt far beyond the Ekdals' means.
Act IV begins at dusk with Gina bidding farewell to two sweethearts she has just photographed. This heavy-handedly symbolic departure prefigures the demystification of, to recall Gregers' phrase, the Ekdals' "tableau of familial affection." In learning Gina's past and the extent of his family's dependence on Werle, Hialmar can no longer sustain his fantasies of himself as breadwinner and father. Much to Gregers's disbelief, this demystification does not bring illumination to the household but its opposite.
Once again, light/dark oppositions structure the dialogue. As Gregers observes, the "light of transfiguration" fails to shine forth from the couple after their confrontation. Instead, "dullness, oppression, and gloom"—perhaps reminiscent of the smoke Gregers produced in the stove fire—pervades the household. As noted above, Gregers expects such light to fill the household as he pathologically imagines Hialmar as a "shining light" among men. He suffers, as Relling will argue later, a disease of hero-worship and romantic idealization. Gregers's fantasies of idolatry underpin his logic of redemption. In finally becoming himself, Hialmar would attain the ideal and then forgive his fallen wife by raising her to his own exalted level. The ideal would save them all.
Hialmar all too readily parrots his friend's gospel, returning from their walk completely converted to the claim of the ideal. In this act especially does his speech ring heady and bombastic, petty and cruel. Note, for example, his appeal to the "breadwinner's dream" of providing for a well-to-do-widow. Hialmar's hyperbole is clearly aggressive in intent. He conjures his death to torment the wife who has "betrayed" him.
In response to Gregers and her husband's language of light/dark, spiritual tumults, taints, poisons, and onward, Gina again emphasizes "the practical." Without such a practical wife, the fiery Hialmar would have been far worse off. In particular, Gina delivers one of the more memorable jokes of the play in removing the lampshade in response to Gregers' exhortations. The joke operates by shifting from the plane of Salvationist allegory to physical comedy, from Gregers' impassioned rhetoric to the banal household object. The removal of the lampshade recalls how the petty concerns of the household function throughout the play to deflate the tirades of our would-be romantic heroes.