What is the theme of the night face up by Julio Cortazar?

The theme of "The Night Face Up" by Julio Cortázar revolves around the duality of reality and dreams, exploring the tension between civilization and primitive existence. The narrative contrasts the modern world of a man in a hospital with his vivid experiences as a captive in an Aztec society, highlighting the fragility of perception and the nature of human experience. Ultimately, it questions the boundaries of reality and consciousness, suggesting that what we perceive as real may be as illusory as dreams.