Peter is the mayor of the town and Dr. Stockmann’s brother. He represents the institutional power of the community who has been entrusted with the economic interests of the locals. Peter is also responsible for overseeing the recent construction project involving the baths, so he’s personally implicated in the potential scandal that might unfold should his brother’s report be published. This combination of personal and institutional investment in the success of the baths makes him the primary antagonist toward his brother’s findings. He has a great deal to lose on a personal, professional, and institutional level if the baths aren’t a success. For Peter, the baths simply cannot fail, and, in this way, he is a manifestation of a broader feeling in the town that the future is dependent on the baths. 

The contest between Peter and his brother is even more profound due to their personal differences. Peter embodies a rigid inflexibility, cynical self-interest, and politicking. He believes that his brother has a “hatred of authority” (45), one that he—as the embodiment of institutional authority—feels very personally. The report about the poisoned water thus becomes a proxy war between two brothers with very different personalities, with Peter unable to countenance defeat to his brother because he would feel it as more than just an administrative loss. 

By the final act, however, Peter begins to fear that he has gone too far. The chaotic meeting and the attack on the Stockmann home lead him to believe that his brother will “ruin” his family as well as the town. He urges Dr. Stockmann to act as a “responsible man” but is unable to see the irony in his request. Dr. Stockmann refuses to compromise, provoking Peter to play his final card, accusing his brother of being personally invested (through Kiil) in the project by manipulating the stock price of the baths for his personal benefit. This is a comforting lie for Peter, as he wishes to believe that his brother is corrupt, rather than principled, to avoid reflecting on his own failings. In choosing falsity over reality, he is the embodiment of the misguided community.

Hovstad is the editor of The People’s Daily Messenger. In a small community, it provides one of the most radical critiques of the status quo. he’s proud of his identity as a radical, embracing Dr. Stockmann’s discovery as part of this war against “that smug cabal of old, stubborn, self-satisfied fogies” (23). 

Hovstad functions as the representative of a progressive radical, giving voice to a left-wing social critique that attacks the forces of capital that he believes govern the town. To some extent, Hovstad is vindicated. When the issue of Dr. Stockmann’s report emerges, the same “cabal” that he criticized—led by Peter—launches a war against Dr. Stockmann to defend their material interests. Unexpectedly for Hovstad, however, the entire community sides with the capitalist elite against Dr. Stockmann, suggesting that the community itself is far less radical than Hovstad once imagined.

At the same time, Hovstad’s own corruptibility serves as a critique of radicalism. Though he may preach a form of radical politics when he has no power, Hovstad is slowly neutered in his radicalism. He’s not as sincere in his criticism of the institutions as he implied. He’s hypocritically willing to benefit from the same capital institutions that he rails against, to the point where he refuses to print Dr. Stockmann’s article or support Dr. Stockmann in his campaign against the local elites. 

Furthermore, he later approaches Dr. Stockmann with an offer, saying that he will publish the article in return for financial backing for his newspaper. Hovstad may have claimed to be acting in the interests of the people, but he reveals that he is only ever interested in benefiting himself.

Catherine is Dr. Stockmann’s wife. She’s a kind hostess in the play’s opening scene, entertaining guests and looking after her children. She handles this role with relish. She loves her family and supports her husband, so she is pleased to help him in any way that she can. This level of mutual support illustrates the happy, peaceful position from which Dr. Stockmann falls.

When she learns of her husband’s findings, Catherine is initially supportive. As with everything in their family, she trusts his judgment to do the right thing. As events unfurl, however, and as the family finds itself ostracized by the community, Catherine begins to disagree with her husband. She comes to side with Peter, pleading with her husband to abandon his moral crusade in the name of the family. She believes in putting her family’s survival first, rather than any principle or the health of people she doesn’t know. Whereas Peter challenges his brother in the name of profit, Catherine offers a more direct, emotional call for Dr. Stockmann not to endanger his family. From her, the call is much more tempting, yet Dr. Stockmann refuses even his wife.

At the beginning of the play, Captain Horster is one of the few characters who is explicitly apolitical. He has little interest in discussing radical politics with Hovstad or involving himself in the publication of a report he doesn’t understand. When the other characters are talking about such matters, he often sits quietly and observes. He has a wealth of experience, having traveled further and for longer than any of the other characters. He’s something of an outsider, but purposefully so, believing that his quiet observation is a much more useful approach to the tumultuous world than involving himself in anything that he doesn’t understand.

As the plot develops, Captain Horster begins to play a more active role in the activities of the town. He’s still unsure of the contents of Dr. Stockmann’s report, but he’s appalled that Dr. Stockmann is being silenced. This is an affront against free speech, so he offers up his own home as a venue for Dr. Stockmann’s announcement. That this meeting is taken over by the bureaucratic forces, led by Peter, furthers Captain Horster’s belief that the townspeople are in the wrong. He never explicitly condones the contents of the report, but he believes that the report should be read. Captain Horster is a supporter of free speech in this way; his apoliticism masks his sincerely held beliefs about the importance of allowing people to talk freely. 

Captain Horster, like Dr. Stockmann’s family, is punished for his actions. He is stripped of his captaincy, an attack on a significant part of his identity. Nevertheless, he remains firmly committed to Dr. Stockmann’s right to speak, refusing to alter his beliefs in the face of censure, criticism, and threats. The character of Captain Horster thus shows that free speech is not necessarily a binary political position: He remains detached from the central intrigue of the report but believes that Dr. Stockmann should not be censored.