What Is It Like to Be a Bat?

Nagel's central claim is that an organism has conscious mental states if and only if there is something it is like to be that organism—something it is like for the organism . This subjective character of experience cannot be captured by any objective, reductionist account of the mind. Nagel rejects the assumption that reductive materialism can explain consciousness without remainder, because any physical description of a bat's echolocation leaves out what it is like for the bat to experience it. The paper does not conclude that physicalism is false; Nagel explicitly says that would be wrong to assume, since physicalism itself is imperfectly understood . The target is the adequacy of our current conceptual framework, not a positive alternative metaphysics.

Nagel chose bats because they are mammals, so we naturally assume they have conscious experience, yet their primary mode of perception—echolocation—is radically different from any human sense . Bats navigate and detect objects by emitting sounds and interpreting echoes, a perceptual system that is functionally analogous to vision but experientially alien to us. This combination of assumed consciousness and profound sensory difference makes the bat an ideal case for separating the objective facts about a perceptual system from the subjective experience of using it. We can know everything about bat sonar and still have no idea what it is like to perceive the world that way. The bat thus illustrates the gap between third-person description and first-person experience.

The essay is widely regarded as one of the most influential texts on consciousness in twentieth-century philosophy. Daniel Dennett, despite sharply disagreeing with Nagel on key points, acknowledged it as 'the most widely cited and influential thought experiment about consciousness' . The phrase 'what it is like' has become the standard locution in consciousness studies for identifying subjective experience, largely due to Nagel's formulation . The paper is frequently cited in philosophy of mind, cognitive science, and animal cognition, and it is credited with helping to establish the 'hard problem' of consciousness as a central philosophical concern, even though Nagel did not use that term. Its influence extends beyond academia into broader discussions of whether science can fully explain subjective experience.

Dennett denies Nagel's claim that a bat's consciousness is fundamentally inaccessible to third-person investigation. He argues that any 'interesting or theoretically important' features of a bat's experience would be amenable to empirical observation. For instance, bats cannot detect objects beyond a certain range because echolocation has physical limits, and such facts about bat experience can be discovered through scientific experiment . Dennett also points out that Nagel's question was not entirely new; B. A. Farrell had raised a similar point in a 1950 article in Mind . Dennett's broader position is that the apparent mystery of subjective experience dissolves once we abandon the intuition that there is an irreducible inner theatre of consciousness waiting to be described.

Akins, a neurophilosopher, argues that many questions about a bat's subjective experience depend on unanswered neuroscientific questions about how a bat's brain actually processes echolocation. Nagel, on her view, is too quick to rule out the possibility that detailed neurophysiological investigation could reveal what bat experience is like . Where Dennett attacks the very idea of an inaccessible subjective realm, Akins challenges Nagel's methodological pessimism: the fact that we do not currently know what it is like to be a bat does not mean neuroscience cannot eventually tell us. Her critique is internal to the scientific study of consciousness, whereas Dennett's is more deflationary about the concept of subjective experience itself.

A frequent misreading is that Nagel claims physicalism is false or that consciousness is non-physical. Nagel explicitly does not draw this conclusion. He writes that it would be wrong to assume physicalism is incorrect, because that position is also imperfectly understood . His point is epistemic and conceptual: our current concepts are inadequate to bridge the gap between subjective experience and objective physical description, not that no such bridge exists in principle. A second misreading treats the essay as a defence of mysticism or anti-science. Nagel's argument is naturalistic in spirit: he is asking what a science of consciousness would need to look like if it were to account for the very phenomenon that makes consciousness puzzling in the first place.