In a world in which the atrocities of fascism can take hold of human emotions, Ionesco classifies logic as absurd and inexplicable, beyond human rationality. The Logician is parodied for his comic missteps in proving even a simple syllogism; when the Old Gentleman asks if, according to the syllogism, his dog must be a cat, the Logician replies: "Logically, yes. But the contrary is also true." Ionesco further demonstrates the inapplicability of logic to human emotion as he cross-cuts dialogue between the Logician's proof and Berenger's fumbling attempts to provide some coherent reason for his unhappiness. Several key lines assail the inconsistency of logic. Berenger's claim that "Life is a dream" points to life as an absurd undertaking that follows the fractured logic of a dream. Moreover, it accords with his feeling that he leads an unconscious existence with no responsibility (for one has no conscious control over a dream). He later amplifies this doubt as he admits, "I sometimes wonder if I exist myself." His statement contradicts the well-known philosophical premise of 17th-century philosopher Rene Descartes: "I think, therefore I am." For Descartes, the ability to think is the only proof of existence. For Berenger, thought not only fails to certify existence, it even casts doubt upon existence. This doubt articulates the foundation of existentialist philosophy, the formula "existence precedes essence." This important dictum of Kierkegaard's states that humans are born ("existence") before they gain any soul or meaning in life ("essence"). As Berenger (and Ionesco) sees it, neither physical nor even mental existence is enough to count for true existence. Although he does not yet know it, he needs a willful life of responsibility committed to something significant (this will become apparent later in the play).
Ionesco makes plausible the eventual mass transformation into rhinoceroses through two specific stagecraft techniques in this first part. He subtly introduces the first rhino into the play, allowing the sound of the beast to amplify slowly. The off-stage presence of this first rhino piques the audience's interest as well and keeps its existence (or stage existence, at least) in doubt. Ionesco also plants the seeds of collective consciousness in this first scene through dialogue devices; during and after the rhino's appearance, the characters all exclaim the same things ("Oh, a rhinoceros!" or "Well, of all things!") at nearly the same time. Furthermore, two separate, simultaneous dialogues—between Jean and Berenger and between the Logician and the Old Gentleman—discuss similar ideas, sometimes even using the same exact language.