Communication
Communication is one of the play's central themes. The Old Man and Woman constantly miscommunicate, remembering important details of their shared past in entirely different ways. In a similar vein, they never actually seem to listen to each other or their guests, but rather are throwing out disconnected comments and stories. This theme comes to a head at the end of the play when the message that the man has been talking about for the entire play is delivered. When this moment finally arrives, the orator is revealed to be deaf and mute, meaning he is unable to speak in a communicable way, rendering the man's message entirely incomprehensible. Communication appears and reappears in the play as a failure between two people to meaningfully exchange thoughts and feelings. They are left only with their fragmentary words and phrases.
Reality and Illusion
Another important theme in the play is the nature of reality. The man and woman describe various shared memories of other places, like Paris, but always remain in the room. The man claims to have invited many people to hear the recitation of his message but we never actually see the guests. He and his wife shuffle around the chairs in their room to accommodate these guests and talk to them at length, but no one is ever actually heard talking in response. When describing their lives together, the man and woman have entirely contradicting accounts of their shared past. The woman comforts the man by saying he could have had a brilliant career as a general or politician, despite there being no evidence of it in his comments. These moments draw attention to the tenuous reality the couple has constructed for themselves, and how tied it is to various illusions. The couple relies on these falsehoods to protect themselves from their bleakly empty present.
Theatricality
Theatricality is also an important theme in the play, which has many moments that raise questions about the nature of theatrical performance itself. The man claims to have an important message to impart, yet he chooses to communicate it through someone else, in the same way a playwright writes for an actor. He and his wife also host guests and arrange chairs in a semicircle—not unlike an audience for a physical theater. These actions all depend on each other, as the man needs the orator to recite his message and he needs the guests as an audience to hear it. He believes that otherwise, his message will be essentially incoherent, reduced to yet another rambling comment to his wife. The tragedy of this is that the orator is completely unable to speak, as he is deaf and mute, and the audience is unseen. His message appears to be unshared and unspoken. In this way, in keeping with the idea of absurdity, the play seems to cast doubt on theater's ability to actually communicate truth and meaning, as all of the man's efforts are in vain.
The Absurd
Fitting with many of the previous themes, the play deals extensively with the nature of the absurd. It contains many strange contradictions. The man and woman are husband and wife, yet she comforts him and babies him in the way a mother would. The audience for the man's speech is unseen for the entire duration of the play, but at the very end there is muffled speech and laughter from an undetermined source. The orator appears as a real, embodied individual, despite the rest of the guests seeming to be imaginary. The couple shares memories of parents and children, but none ever appear or are named. The play constructs these paradoxical situations as a means of exploring absurdity at its extreme. These moments reveal the tragic humor inherent to trying to exercise control over these various aspects of life.
Status
Another theme in the play is status and power. The man expresses continual frustration about his lack of status as a general factotum, while his wife keeps telling him he was wrongfully denied a more illustrious and high-ranking career. This desire seems to drive his intense need to be admired for the supposed brilliance of his message. Later, the man and his wife express intense deference toward the emperor, who arrives near the end of the party. Despite the fact that he is invisible, they pledge unflagging devotion to him. All of these moments are rendered as extremely ridiculous, as the man and woman exist in a space devoid of other people. What Ionesco seems to suggest here is that status is one of the only constants of the characters' lives, and that its effects are present even in the absence of anything tangible.
Sexuality
Sexuality is also an important theme in the play. The man and woman's relationship is very unusual. Despite the fact that they are a married couple, they seem to take on a more parent-child relationship in moments, with the man's wife acting as his mother as she holds and comforts him. In contrast, the man's conversation with Madame Belle suggests the spark of a former affair, and the woman's flirtations with Madame Belle's husband are overtly sexual and bizarrely physical, as she gyrates in front of him. As both of these characters are unseen, and perhaps imaginary, the suggestion here appears to be that these characters are unable to find any tangible outlet for their sexual feelings and are forced to, instead, project them onto invisible beings.
Dependency
Dependency is another pivotal theme in the play. The man and woman rely on each other entirely throughout the play. The man needs the woman's comfort to stave off his feelings about his underwhelming career. The woman needs the man to recite his memories to her, despite having heard them many times before. Later in the play, the woman supports the man in his endeavor to accommodate and impress his many guests. Despite this, their relationship seems to have many issues. They flirt with some of the guests and disagree about major parts of their past. In their joint portrayal, the man and woman both come off as entirely dependent on one another to hold up the illusions of their empty world.