In A Doll’s House, the lamp represents both false security and the illumination of truth. In the play, Ibsen introduces the lamp as a prop that characters use as protection and as a device to reveal truths. The lamp first appears in act 2 when Nora is about to reveal her secret—her past forgery—to Dr. Rank. She tells him,

I know you are my truest and best friend, and so I will tell you what it is. Well, Doctor Rank, it is something you must help me to prevent.

Her confession, however, is interrupted by his admission of a secret love for her.

I was determined you should know it before I went away, and there will never be a better opportunity than this. Now you know it, Nora. And now you know, too, that you can trust me as you would trust no one else.

Instead of being a vehicle to shine light on truth, the lamp becomes a symbol of false cheer. Disturbed by Dr. Rank’s revelation, Nora immediately decides not to divulge her secret to Rank but commands the maid to bring a lamp into the room.

NORA. Helen, bring in the lamp. [Goes over to the stove.] Dear Doctor Rank, that was really horrid of you.

RANK. To have loved you as much as anyone else does? Was that horrid?

NORA. No, but to go and tell me so. There was really no need—

RANK. What do you mean? Did you know—? [MAID enters with lamp, puts it down on the table and goes out.] Nora—Mrs. Helmer—tell me, had you any idea of this?

The lamp becomes a symbol of safety; Nora wants to light up the room—banishing any darkness or suggestion of romance—and seek the warmth of the stove. Light and heat represent security, innocence, and childlike protection from Dr. Rank’s unexpected amorous advances and, most importantly, the truth of his love for her. Nora wants to be shielded from this truth. After turning on the lamp to create a safe and well-lit environment, she admonishes Rank:

You can do nothing for me now. Besides, I really don't need any help at all. You will find that the whole thing is merely fancy on my part. It really is so—of course it is! [Sits down in the rocking chair and looks at him with a smile.] You are a nice sort of man, Doctor Rank! Don't you feel ashamed of yourself now the lamp has come?

In other words, how can he violate the bright atmosphere of false cheer with uncomfortable truths?

In act 3, the lamp once again seems to symbolize illumination and truth-telling and eventually does so after a false start. This final act opens with a lamp burning on a table at the center of the stage. Ibsen presents revelations in the third act but not in a straightforward way.

After Torvald discovers from Krogstad’s first letter that Nora had committed forgery, he reacts by scolding her for her crime; he cannot bear her confession of the truth. He tells her that she has ruined his reputation and happiness and that they must present false appearances:

I must try and appease him in some way or another. The matter must be hushed up at any cost. And as for you and me, it must appear as if everything between us were just as before—but naturally only in the eyes of the world.

Then when Torvald receives a second letter from Krogstad, he moves to the lamp in order to read it and learn the truth.

HEL. [standing by the lamp]. I scarcely have the courage to do it. It may mean ruin for both of us. No, I must know. [Tears open the letter, runs his eye over a few lines, looks at a paper enclosed and gives a shout of joy.] Nora! [She looks at him questioningly.] Nora! No, I must read it once again. Yes, it is true! I am saved! Nora, I am saved!

When Torvald discovers that Krogstad cancelled Nora’s debt, he rejoices that he is saved—with Nora as an afterthought. Nora then realizes that her truth cannot be accepted by Torvald and that Torvald cares more about himself and appearances than about her as a complete person and separate adult. He still sees her as a powerless doll and child.

At the end, she sits on one side of the table and he on the other side; with the lamp between them, she tells him that she is leaving him. The lamp provides a harsh light on the true state of their marriage:

But our home has been nothing but a playroom. I have been your doll wife … and here the children have been my dolls. I thought it great fun when you played with me, just as they thought it great fun when I played with them. That is what our marriage has been, Torvald.

In fact, the light of the lamp illuminates this truth to Nora—"I have never felt my mind so clear and certain as tonight”—and motivates her to grow and exit her cloying domestic situation.