In his essay “What Is It Like to Be a Bat?” American philosopher Thomas Nagel critiques theories of the mind. Published in The Philosophical Review in 1974, this philosophical and expository piece is primarily geared towards academics, students, and anyone with an interest in philosophy of mind, consciousness, and subjective experience. This study guide references the original publication in The Philosophical Review, Vol. 83, No. 4.

Nagel, a university professor of philosophy and law, emeritus, at New York University, focuses primarily on philosophy of mind, political philosophy, and ethics. In “What Is It Like to Be a Bat,” he delves into the topics of consciousness, subjective experience, the problem of other minds, and the limitations of physicalist theories of mind. The essay has shaped ongoing debates in philosophy of mind and consciousness studies.

The essay begins with a critical examination of the physicalist theories of consciousness that were dominant in 1970s philosophical discourse. These theories proposed that consciousness and the workings of the mind could be explained solely in terms of physical processes. Proponents of these theories believed that the mental states we ascribe to consciousness, such as thoughts and feelings, could be reduced to and explained by the physical states of the brain.

Physicalism is more broadly understood as reductionism, the belief that complex systems can be understood by breaking them down into their fundamental, simpler parts. However, Nagel criticizes “reductionist euphoria,” or the enthusiasm and optimism some scientists and philosophers display when they claim that all mental phenomena can be fully explained by simpler, physical processes (435). He argues that in the philosophy of mind, such theories fail to capture the true essence of conscious experience by not considering what it feels like to be a particular conscious being. According to Nagel, this is a fundamental component of any conscious experience and cannot be ignored in any comprehensive theory of consciousness.

Nagel invites his readers to engage in a thought experiment: To imagine what it might be like to be a bat. This exercise requires the reader to try and envision the world from the perspective of a bat, a creature that is fundamentally different from humans in terms of sensory perception and experience. The primary mode of sensory experience for a bat is echolocation, a method of perceiving the environment that is vastly different from the five senses that humans typically rely on—sight, sound, touch, taste, and smell. Echolocation involves emitting sound out to the environment and listening to the echoes that bounce back from various objects. By doing this, bats locate, navigate, and identify their surroundings in complete darkness.

Attempting to imagine such an unfamiliar sensory world is a challenging task that underscores Nagel’s point about the inherently subjective nature of consciousness. The hypothetical sensory world primarily mediated by echolocation is dramatically different from the human sensory experience; Nagel asserts that this difference in perception makes it almost impossible for us to conceive what it is exactly like to be a bat. Each organism, according to Nagel, experiences the world in a way that is intrinsically tied to its unique biological makeup and sensory capabilities. Even if we understand echolocation from a scientific standpoint and can describe it in objective terms, this does not translate into a subjective understanding of what it feels like to perceive the world in the way a bat does.

Nagel argues that our inability to grasp what it is like to be a bat does not imply that bats do not have experiences (nor lack consciousness). They can have experience even if those experiences are unique to their own sensory worlds and beyond our ability to comprehend fully. In Nagel’s words, “to deny the reality or logical significance of what we can never describe or understand is the crudest form of cognitive dissonance” (440).

In addition to exploring the subjective character of consciousness, Nagel also delves into the philosophical problem of other minds. This involves the question of how we can know that other individuals, be they humans or nonhuman animals, have minds and experiences similar to ours when we can’t directly perceive their experiences. Nagel argues that if we accept that other humans have minds and experiences akin to ours based on their similar physical constitution and behavior, despite our inability to access their subjective experiences, then by the same token, we should extend this understanding to other animals, such as bats. This line of reasoning encourages us to acknowledge the existence of a rich tapestry of conscious experiences in the natural world, beyond the human experience.

Nagel concludes that our current scientific methods and concepts might be insufficient to fully grasp the nature of subjective experience. He calls for a new kind of objective science that can bridge the gap between subjective experiences and physical processes, suggesting that the question of what it is like to be a bat is less about answering the question definitively and more about illustrating the limitations of our understanding and the inherent subjectivity of consciousness.