In an act of both foreshadowing and dramatic irony, during Act One, Torvald criticizes Krogstad’s forgery and deception, declaring that such acts will inevitably have a poisonous effect on the man’s children:
Just think how a man with a thing like that on his conscience will always be having to lie and cheat and dissemble; he can never drop the mask, not even with his own wife and children. And the children—that’s the most terrible part of it, Nora [...] A fog of lies like that in a household, and it spreads disease and infection to every part of it. Every breath the children take in that kind of house is reeking evil germs.
Despite Torvald’s extreme declaration, what he does not know is that his own wife has also committed an act of forgery and deceit and has been keeping this shameful secret to herself for years. Torvald’s adamant insistence that Krogstad’s actions will have harmful consequences is therefore exceedingly ironic, since, earlier in the very same scene, the audience watches as Krogstad blackmails Nora about her own loan.
Additionally, the seemingly contaminating “fog of lies” that Torvald refers to foreshadows the later revelation of the poisonous effect Nora’s secret has had on her own conscience and marriage. The pressure Nora feels to wear a mask of doll-like perfection while at the same time maintaining the success, health, and safety of her family for no credit or acknowledgement is immense and stifling. With this scene, Ibsen demonstrates how the gendered expectations forced upon women when they are confronted by crises can only lead them to make difficult, sometimes damaging choices.
Nora, chafing at constantly being underestimated, ends up confiding in Mrs. Linde near the start of Act 1, seemingly wanting to discreetly unburden herself by sharing her secret about the loan. In an act of situational irony, though, Nora’s attempt to ease some of her worries and frustrations ultimately exacerbates her circumstances later in the play:
Nora: You’re just like the rest of them. You all think I’m useless when it comes to anything really serious…
Mrs. Linde: Come, come…
Nora: You think I’ve never had anything much to contend with in this hard world.
Mrs. Linde: Nora dear, you’ve only just been telling me all the things you've had to put up with.
Nora: Pooh! They were just trivialities! [Softly.] I haven’t told you about the really big thing. [...] Nobody must know about it, Kristine, nobody but you.
Telling Mrs. Linde this secret turns out to backfire on Nora spectacularly, ironically leading to even more troubles and the eventual dissolution of her marriage. Following Nora’s confession, Mrs. Linde condemns the fact that Nora has introduced deception into her marriage, and it is Mrs. Linde’s very dedication to truthfulness that ultimately cements the chain of events that lead to Torvald’s discovery of Nora’s deception. Nora’s attempt to unburden herself from the stress of keeping her family afloat thus ends up leading to even more trouble and hardship.
Dr. Rank’s enjoyment and indulgence of all things unhealthy and decadent following the diagnosis of his terminal illness is an example of situational irony, especially considering that he traces his spinal tuberculosis to his father’s own possession of these habits:
Torvald.: You seemed to be having a pretty good time upstairs yourself.
Rank: Capital! Why shouldn’t I? Why not make the most of things in this world? At least as much as one can, and for as long as one can. The wine was excellent [...] Well, why shouldn’t a man allow himself a jolly evening after a day well spent?
The joy Dr. Rank takes in letting loose, eating and drinking to his heart’s content, is also tinged with irony because of the fact that he is only able to reach such a stage of enjoyment after finding out such bitter news. His desire to live to the fullest for whatever time he has left foreshadows Nora’s imminent decision to leave Torvald and enjoy her own life for as long as she can. By choosing to indulge in his desires, Dr. Rank sets an example for Nora to follow, demonstrating the fact that endings can also herald new beginnings.
As Nora and Torvald argue in the aftermath of the big reveal regarding her loan, Torvald asserts that no one could ever sacrifice their honor in the name of love, calling Nora a stupid child for thinking so in a perfect example of situational irony:
Nora: All the time Krogstad’s letter lay there, it never so much as crossed my mind that you would ever submit to that man’s conditions. I was absolutely convinced you would say to him: Tell the whole wide world if you like. [...] When that was done, I was absolutely convinced you would come forward and take everything on yourself, and say: I am the guilty one. [...]
Torvald: I would gladly toil day and night for you, Nora, enduring all manner of sorrow and distress. But nobody sacrifices his honor for the one he loves.
Nora: Hundreds and thousands of women have.
Torvald: Oh, you think and talk like a stupid child.
As the passage above demonstrates, although Nora is the one being insulted for her supposed childishness, Torvald is the one who is behaving like a petulant child. Exposed as a hypocrite and fickle man whose love is conditionally dependent on absolute doll-like obedience, Torvald scrambles to rescue his marriage from a situation of his own making (i.e. his bad reaction to the IOU letter). Nora’s revelation that she was planning suicide in order to protect Torvald makes his self-preservationist tendencies all the more disappointing and even pathetic in the face of her devotion, which he now finds himself forever excluded from.