In Nagel’s essay, consciousness is the central theme. He defines it as the subjective quality of experience, the “what it is like” to be or feel something. According to Nagel, consciousness cannot be fully explained by objective scientific methods because it is inherently subjective. The essay explores the challenges of understanding consciousness, particularly from the perspective of a different species, such as a bat, highlighting the limitations of our current understanding and methodologies.

In the context of Nagel’s essay, dualism refers to the philosophical view that the mind and the body are distinct and separate entities. Dualism influences Nagel’s argument about the difficulty of understanding another creature’s consciousness. Although Nagel does not explicitly advocate for dualism, his argument that conscious experience is subjective and unknowable by other beings suggests a divergence from strict physicalism, which views consciousness as a physical phenomenon.

The term “experience” repeatedly occurs in Nagel’s essay and refers to the subjective perception and interpretation of events or phenomena. Nagel argues that each organism has a unique experience significantly shaped by its physical and sensory attributes. Understanding the experience of another organism, such as a bat, poses a significant challenge due to the fundamental differences in sensory perception and interpretation.