Isabel has had three years to think of Mrs. Touchett's suggestion that Madame Merle had a hand in her marriage. She still believes that while Merle may have helped Osmond get married, she certainly did not put the idea into Isabel's head. However, she has noticed that Merle has had a noticeable absence -- Merle has distanced herself from the couple. Madame Merle had even mentioned it once to her, saying that she had known Gilbert Osmond for so much longer than Isabel and did not want to seem too familiar. Isabel had once admired Madame Merle's "trick for life" (353), wondering how she could herself imitate her by turning herself into something like a silver surface. Now though, she does not want to imitate this.
One day, Isabel returns to the house after a walk in the garden. She is going through the drawing room, when she sees Madame Merle has come for a visit. She receives a shocking impression: Madame Merle is standing, while Osmond is sitting down. (This would have been a case of poor manners during the time - Osmond should not have been seated unless his guest had already been seated.) She notes that the two are sitting silent, as if they are familiar with each other. As soon as Osmond notices Isabel's arrival, he jumps up, as if he knows his mistake.
Madame Merle tells Isabel she has come to discuss Edward Rosier's quest for Pansy's hand in marriage. Rosier comes to visit Merle often, begging her to intercede on his behalf. Isabel responds sarcastically to Merle's claims to wash her hands of the whole affair. Merle wants Isabel to speak to Pansy - to find out if Pansy has actual feelings for Mr. Rosier. Isabel accuses her of being too much "interested" in the whole affair (361). Merle then tells her Mr. Rosier is afraid that Lord Warburton is falling in love with Pansy. Isabel says that she knows Lord Warburton is charmed by Pansy, and Merle almost immediately asks if Isabel has told her husband this. Merle thinks it is "kind" of Lord Warburton to rest his eyes on Pansy. Isabel agrees with Merle that a match with Lord Warburton might be good for Pansy. Merle thinks that Isabel can make Lord Warburton marry Pansy - that she has a great influence over him.
Isabel is surprised to learn that Merle knew about her rejection of Warburton. Merle suggests that Isabel owes him the reparation of making a match for him with Pansy.
Isabel is not excited by the idea of Pansy and Lord Warburton marrying initially, but she allows the idea to settle in her mind. She realizes that she would be acting her part as a good wife if she were to assist the match in being made. Yet, she is also surprised that Lord Warburton would be attracted to Pansy -- for Pansy is very different from Isabel herself. She thinks of Pansy as small, an innocent but limited creature. Nevertheless, Isabel contents herself with the idea of providing a service for her husband.
Of course, Isabel thinks to herself, Edward Rosier presents a problem. Isabel had tried not to inform herself of Pansy's feelings for Mr. Rosier, but she finds that she knows that Pansy thinks the world of him. She wonders how tenacious Pansy will be in clinging to her idea of Edward Rosier - Isabel then begins to believe that Pansy could cling to just anything. Isabel after all thinks more highly of Lord Warburton than Edward Rosier.
This scene within Isabel's mind takes place as Isabel is having another of her Thursday gatherings. Lord Warburton is there, speaking with Pansy. Isabel knows that if she leaves the two alone in a room together, Lord Warburton may declare his feelings for Pansy and set in motion a proposal. But she hesitates to do this act that would please her husband. Lord Warburton ends up leaving for the night without a moment alone with Pansy.
Isabel then sits alone in a room staring at the fire. Her husband enters the room, and asks about Lord Warburton's interest in Pansy. Isabel says she has been waiting for Osmond to give it a name. The narrator tells us that Isabel has decided not to take it for granted that her husband would like Lord Warburton -- and further, she is motivated by the thought that Osmond's declaring a desire to see Lord Warburton propose would show that Osmond did in fact want something from the world. She thinks it is his constant intimation that he wants nothing of the world - that nothing could be good enough for him. Thus his declaration of a desire for a proposal from Lord Warburton would be a lapse in consistency. Isabel then also thinks to herself that her husband may very well decide to take this opportunity to humiliate Isabel.
Osmond behaves well on this occasion though. He simply asks Isabel to help along the match. He then suggests to Isabel that she can make Lord Warburton do whatever she would like him to do - and that she should use this influence to make him marry Pansy.
This is the most famous chapter of the novel and its climax. Unlike other novels, where the climax takes primarily in terms of external events, all of the tension of the novel gathers in Isabel's mind. The scene consists only of her thinking through the motivations of the various people around her. It opens with Isabel absorbed in looking at the situation as Osmond has presented it to her. She has an unexpected recognition that she does in fact have an influence on Lord Warburton. She wonders if he has a desire to please her. The answer frightens her, because she realizes that if he does want to please Isabel, then it is likely that he would marry Pansy for the sake of his love for Isabel. She thinks it impossible that he would be in love with both of them.
Other thoughts then crowd to the foreground of Isabel's mind. She has realized that Osmond was in more direct communication with Madame Merle than she ever suspected.
Isabel then thinks to herself that she would have liked to give Osmond proof of her own loyalty - but that everything Osmond touches withers away. So too her good intention: realizing that he expects her to intervene makes her feel that there is something horrible in doing so. She thinks about her marriage. For the first year, it was good, but gradually she began to realize that the shadows she perceived in Osmond's character were not figments of her imagination. He was never violent, but she had gradually begun to realize that her husband hated her. He hated her for being different, and for not being malleable enough for him to change her. Sometimes she felt she had even deceived him when they first got together -- if not in intention, in fact. She had acted more timid than she really was, had felt small in his presence. She realizes that Osmond had not disguised himself either. She simply had not seen his whole person.
She speculates on her motivations for marrying him. She had thought of certain of his features as together making a great figure. She thought he was helpless and ineffectual, but this made her feel tenderer towards him. She realizes she had wanted to give him the means to be effectual. If it had not been for her money, she would not have married him, she realizes.
Isabel feels embarrassed at the thought that she might have married on a factitious theory. But she then defends herself in thinking of the personal qualities she admired in him. She found him to have a fine mind - and this she still believed. She felt she had almost lived in his mind, "it appeared to have become her habitation" (376). In fact, she wondered that he did not hate her more. She remembers the first hint he had given of his future dislike for her: he had told her she had too many ideas once before he had even proposed marriage. She had not thought much of it then. But she had wanted to marry so as to share her ideas.
She had kept her character in reserve, and he had not known this until they had already closed the door behind them. He seemed to take personal offense at the way she looked at life.
Gradually she had realized she was living in the house of darkness. "Osmond's beautiful mind indeed seemed to peep down from a small high window and mock at her," the narrator tells us (377). She had realized he was incredibly egotistical, and that he hated everyone but three or four people. She learned a lot from his recognition of the baseness of life, but at the same time, she recognizes that the reason he holds it in contempt is so as to extract recognition of his own superiority. He was not really indifferent, she discovered. He was unable to live without society. She realizes that he has an aristocratic ideal, an immense esteem for tradition. He expects her further to live in accordance with such traditions. She feels suffocated in this rigid system though.
She realizes that her husband was ashamed of her, with her disregard for tradition. She is most offensive insofar as she has a mind of her own. He had wanted her to be more like a garden for himself, rather than having a mind of her own. His contempt for her had then turned into a comfort of his life.
She wonders what is going to come, what sort of obstacles will present themselves before the couple. She was aware that he was unhappy about Ralph's staying in Rome for some time. But she could not pretend to be indifferent to Ralph. She felt after all a little light in her life from being with Ralph, as if he had been her brother. If Gilbert was jealous it was because Ralph was generous and Gilbert was not. Ralph was just as intelligent, and better than Gilbert. She wonders how Ralph knew about Gilbert.
Isabel feels she is doing her cousin a kindness in not telling him of her true state. Finally, she gets up from her meditative vigil at four in the morning. She then thinks back to what she saw between Madame Merle and Gilbert Osmond.
The situation between Lord Warburton and Pansy presents us with an interesting situation that allows Isabel to think about the right motivations behind an action. If Lord Warburton is marrying Pansy in order to please Isabel, she sees that it would be wrong of her to take advantage of this. Yet Isabel realizes that this is exactly what Madame Merle and Osmond expect of her: they expect her to have no qualms about using another person for one's own ends. This makes her reflect on the moral character of the people around her.
Chapter 42 shows the psychological realism of the novel. Isabel wants to understand her own motivations and the motivations of those around her -- what is it that makes Gilbert Osmond do what he does? What motive for action should she have had when she married him? She discovers her own motives might have been impure: she had had a theory that Osmond would be great if he had the means, and she had wanted to provide him with the money to do so. She had wanted to be beneficent. She had also felt it a burden to have money, because it made her feel as if she really had to do something with it. It is though an embarrassment to Isabel that she should after all have acted on a financial motive -- this seems like a wrong reason to marry. She also thinks that Osmond's view of social relations is selfish. The only reason he likes to be in society is because it allows him to feel superior to it. Both money and egotism seem to be immoral motivations to Isabel.
As Robert Pippin has pointed out (see works cited), the modern situation that Henry James was facing during his time introduced the possibility that psychological motivations made an action moral or immoral. For example, if Osmond had married Isabel just for his own self-interest and to increase his fortune, it would be immoral. But Isabel had married Osmond because she had wanted to give him the means to further express himself, and this is considered moral. However, the problem being presented in the novel is that psychological motivations only crystallize as such later on in life.
It is important to note the technique that James employs to enter into Isabel's mind. He first of all has set up the scene so that we have only gradually approached Isabel's true state of mind through the speculations of others. We first get Edward Rosier's speculations of Isabel, then Lord Warburton's, then Ralph's, until we finally approach Isabel's own. It is like peeling the layers off of an onion until we reach the core of Isabel's thought. Furthermore, there is an indication that Isabel's own thoughts are very much infected and inflected through her understanding of the thoughts of others. Sharon Cameron (see works cited) has called this the ‘intersubjectivity’ of the novel: the belief that one's mind is not entirely one's own, but rather a consciousness crystallizes as such only once one knows what others are thinking.
Finally, Chapter 42 provides us with insight into James' views on the conventional Old World. Osmond is representative of empty traditions without any intrinsic meaning. He follows them simply to show his own aristocratic value. At best, this Old World is capable of showing itself off through aesthetics -- knowledge about classical art, for example, would let one show off how cultured one is. However, James is questioning whether or not this aristocratic, European view of the world would not benefit from the freshness of an American, moral perspective. Isabel is representative of the New World, and the insights that an open mind can provide to a European outlook. She wants to always look at things for herself, bring her own original perspective, and question the meaning of traditions. Yet it is problematic that she has only two means of expressing herself: money and marriage. There seems also to be a feminist point being made here, especially in Isabel's envy of Lord Warburton. Women did not have enough avenues open to them during this time period for expression of their character, and James seems to be suggesting that they would have something very valuable to add to society if more pathways were open to them to do so.