Outraged that a verdict has been passed against him, Alceste vows to live the rest of days in solitude, away from the society he has come to abhor. He tells Philinte that, in addition to the unfortunate verdict, his adversary has falsely attributed authorship of an obscene book to him. On top of all of this, Oronte has begun supporting the rumor. Philinte encourages Alceste to be reasonable, to challenge the verdict before committing to a life of solitude. Alceste objects, stating that he wants the verdict to stand has a glaring example of "the wickedness" of the times. He reveals his intention to test Célimène's love by asking her to withdraw from society with him.
Oronte demands that Célimène decide between him and Alceste. Agreeing with Oronte, Alceste makes the same demand. Both men agree to concede if Célimène chooses the other. Célimène calls their requests "inappropriate," not wanting to publicly offend the one she does not choose. She decides to let Éliante "be the judge" of her affections.
Éliante refuses to decide between Alceste and Oronte for Célimène, stating that Célimène has a responsibility to be open and honest to all present.
Acaste and Clitandre enter with a letter written by Célimène, demanding that she take responsibility for it. They read the letter, which insults each of Célimène's suitors and describes what she sees as their flaws. Decidedly tired of Célimène's insults, Acaste and Clitandre leave. Oronte follows them out, shocked that Célimène would insult him so. Alceste tells Arsinoé that she has no chance of gaining his love. She leaves, angry.
At this point, Alceste invites Célimène to retreat into solitude with him. She rejects the offer, but says that she will agree to marry him. Insulted, Alceste says that he wants nothing to do with her. Célimène leaves.
Alceste then tells Éliante that he cannot marry her, deeming himself "unworthy." She interrupts him, telling him not to worry, for she plans to devote herself to Philinte. Alceste again states his plan to live somewhere remote from society. As Philinte and Éliante exit, Philinte remarks that they must encourage Alceste to abandon his plan.
In this final act, Molière parallels Alceste's attitudinal separation from the cast with his physical separation. Alceste literally cannot exist in the world of the world of the play. He never comes to terms with his distaste for mankind, and mankind never gives its acceptance of Alceste's behavior. The legal system—a symbol and a voice of the standards and values of the society of the play—continues to find fault with Alceste. He learns that he has lost his court case, which solidifies his decision to retire to solitude.
Though Célimène seems to develop into a more mature, perhaps more loving woman over the course of the play, she ends up not far from where she began, saying, "Solitude is a frightening prospect when you are twenty. I don't feel I have the necessary fortitude or strength to bring myself to take such a decision" (V.iv). Célimène is attached to the society just as much as Alceste is separated from it. We can hardly imagine who Célimène might be or what she might do were she in a setting where she had no access to gossip or flirting. Molière creates the comic image of Célimène and Alceste alone together forever—a disastrous, but hilarious, consequence.
At the very end of the play, Philinte and Éliante announce their love for one another, demonstrating that a true romance can exist in a corrupt world. Molière suggests that selflessness is a prerequisite for such a relationship. Indeed, Philinte and Éliante leave the stage talking not of themselves, but of their responsibility to keep Alceste from banishing himself.
Although Molière's satire targets the corruption of French society, the playwright does demonstrate that this corruption has its limits. At play's end, Célimène is left alone because her letters and gossip have crossed the boundary between innocent fun and real offensiveness. We do not feel much sympathy for her bruised suitors, however, as they expose their own hypocrisy in leaving Célimène. The suitors are perfectly willing to join in the fun of criticizing their acquaintances, provided that they are not included as targets themselves.
The Misanthrope ends with an unlikely happy ending. Philinte and Éliante are the lucky couple—not Alceste and Célimène. Alceste meets the only end that might bring him peace. In reality, the union of Alceste and Célimène would likely not be a happy ending at all. Perhaps Molière honors his protagonist and his stern values by giving him exit from the society he despises.