![What is it like to be a bat? (1974) [pdf]](https://images.pexels.com/photos/5057597/pexels-photo-5057597.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940)
The Full Story
Thomas Nagel, a philosopher at New York University, published "What is it like to be a bat?" as a direct challenge to reductionist approaches to consciousness—the view that mental states can be completely explained by physical brain processes. Nagel didn't choose bats arbitrarily. Bats experience the world primarily through echolocation, a sensory system fundamentally alien to human perception. A bat emits high-frequency sounds and interprets the returning echoes to navigate and hunt, creating a three-dimensional acoustic map of its environment that humans cannot directly imagine. Nagel's argument rested on a crucial distinction: there is something it is *like* to be a bat—a subjective, first-person experience unique to that organism. This inner experience cannot be fully understood by examining the bat's brain structure, neural firing patterns, or behavioral outputs. Even if neuroscientists mapped every neuron involved in echolocation and could predict every behavior the bat exhibits, something essential would remain unexplained: what echolocation *feels like* from the bat's perspective. The paper introduced the concept of "qualia"—the subjective qualities of conscious experience. The redness of red, the painfulness of pain, the specific character of echoic perception—these qualitative aspects of consciousness resist translation into purely objective, third-person scientific language. Nagel argued that this explanatory gap poses a fundamental problem for materialist philosophy, which holds that consciousness is ultimately nothing but physical matter organized in particular ways. The 1974 essay was deliberately brief, spanning only seventeen pages, but its implications proved explosive. Nagel wasn't claiming that consciousness was non-physical or that science could never explain it. Rather, he identified a methodological problem: the very nature of subjective experience creates a barrier that objective scientific methodology, by definition, cannot cross.Why This Matters
The renewed interest in "What is it like to be a bat?" in 2026 reflects urgent, practical concerns in contemporary neuroscience and artificial intelligence. As researchers develop increasingly sophisticated neural mapping technologies and machine learning systems, Nagel's half-century-old argument has become directly relevant to questions scientists face daily. First, the paper challenges neuroscientists to confront what they can and cannot claim to understand. Brain imaging can show which regions activate during conscious experience, but activation patterns don't necessarily explain subjective feeling. Second, the essay directly impacts artificial intelligence development. Companies and researchers building AI systems must grapple with whether consciousness is something their systems possess or could possess, and Nagel's work provides essential philosophical framework for that debate. If subjective experience cannot be reduced to information processing or computational states, then machines might perform perfectly intelligent behaviors without any inner experience—raising profound ethical questions about how to treat artificial systems. Third, the paper has become central to debates in medical ethics, particularly regarding patients in vegetative states or with severe brain injuries. If understanding consciousness requires grasping subjective experience, how should doctors assess whether unconscious patients have any inner life? These aren't merely academic puzzles; they directly influence life-and-death medical decisions.Background and Context
Nagel's essay emerged during a specific moment in philosophy of mind. The 1970s saw intense debate between physicalists—who believed all mental phenomena were ultimately explicable through physical science—and their critics. Nagel's predecessor, Ludwig Wittgenstein, had warned that subjective experience possessed a fundamentally private quality that created philosophical problems. Nagel synthesized these insights into a focused argument that proved more durable than competing critiques. The paper's influence grew steadily through the 1980s and 1990s as neuroscience began mapping the brain with greater precision. Rather than solving consciousness, technological advances made Nagel's problem more acute. Scientists could observe neural correlates of consciousness—brain activities that reliably occur when someone reports conscious experience—yet this correlation did not answer Nagel's question: why does any physical process give rise to subjective experience at all? The concept of "qualia" became central to consciousness studies partly because of Nagel's essay. Philosophers like David Chalmers would later popularize the term "the hard problem of consciousness" to describe exactly the gap Nagel identified. Meanwhile, neuroscientists like Christof Koch and Francis Crick investigated consciousness with the understanding that subjective experience remained philosophically problematic despite their empirical advances.Key Facts
- Published in The Philosophical Review, Vol. 83, No. 4 (October 1974), pages 435–450
- Author Thomas Nagel was a professor of philosophy at Princeton University when the paper was written; he later moved to New York University
- The paper uses bats as the primary example because their sensory system (echolocation) is radically different from human perception, making their subjective experience difficult to imagine
- Nagel's central claim: objective physical science, by its methodology, cannot fully explain subjective conscious experience—the "what it is like" quality
- The essay introduced widespread philosophical use of the term "qualia" to describe subjective qualities of conscious states
- The paper has been cited thousands of times in academic literature and remains one of the most influential 20th-century philosophy papers
- Nagel explicitly rejected both dualism (the view that mind and body are separate substances) and simple mater