What Is It Like to Be a Bat?

Direct Answer

"What Is It Like to Be a Bat?" is Thomas Nagel's 1974 essay, one of the most influential works in the philosophy of mind. Its thesis is that conscious experience has a subjective character — "there is something it is like" to be a conscious organism — and that this subjective character cannot be captured by the objective methods of physical science, no matter how complete they become. The essay is the origin of the now-standard phrase "what it is like," which philosophers use to mark the phenomenal, experiential dimension of mind.

Nagel defines the problem precisely. An organism has conscious mental states "if and only if there is something that it is like to be that organism." There is something it is like to be you — you have experiences from the inside. There is something it is like to be a bat, a dog, presumably. There is nothing it is like to be a rock, a table, or (probably) a thermostat. The "something it is like" is the subjective character of experience, and it is the defining feature of consciousness.

Nagel's argument then targets physicalism and reductionism. Physicalism holds that the mind is physical and that mental facts are physical facts. Nagel argues that this thesis is incomplete, because there are facts — the subjective facts — that are not captured by the physical description. The point is made with the bat: bats perceive the world primarily through echolocation — emitting high-frequency sounds and constructing an auditory "image" of their environment. We can know every objective fact about this system: the physics of sonar, the neurophysiology of the bat's auditory cortex, the functional organization of its behavior. We can even know, in some sense, what it is like for a bat to perceive by echolocation "from the outside." But we cannot know what it is like for the bat — the bat's own experience, from the bat's perspective. The bat's experience is subjectively accessible to the bat alone, and its character escapes us. Therefore, Nagel concludes, physicalism — and indeed any objective account of reality — leaves something out.

Historical Context

The essay appeared in 1974, at the height of the physicalist orthodoxy in analytic philosophy of mind. The identity theory and functionalism were ascendant, and the idea that consciousness might resist scientific explanation was widely dismissed. Nagel's essay broke the consensus. It was the first sustained argument that the subjective character of experience is not merely difficult to explain but systematically resistant to the objective standpoint — a standpoint that is itself a human, and therefore partial, perspective on reality.

Nagel's argument was part of a broader turn. It anticipated Frank Jackson's knowledge argument (1982), which made the same point with a thought experiment rather than a comparative example. It influenced David Chalmers's formulation of the hard problem (1995). And it gave the philosophy of consciousness its central vocabulary: "what it is like," "subjective character," and "the subjective character of experience" all derive from this essay. The essay also belongs to Nagel's larger project of questioning the completeness of the scientific worldview, pursued in books such as The View from Nowhere (1986), which argued that the "objective" view of the world is only one view — the view from nowhere — and that the subjective perspective cannot be reduced away.

The essay's bat was a brilliant rhetorical choice: bats are genuinely alien — mammals with a sensorium built around echolocation — yet clearly conscious. The example forces the reader to confront the limits of imagination and description: we cannot construct the bat's experience out of our own.

Key Arguments & Debates

The argument's core is a claim about the limits of objective knowledge. Any objective description — physical, functional, behavioral — is available in principle to any observer. But the subjective character of experience is available only from the first-person perspective of the subject. Since reductionism aims to explain the mind in objective terms, and since the subjective character is in principle inaccessible from those terms, reductionism must leave out the very thing that defines consciousness.

Nagel's own analysis of the difficulty is subtle. The problem, he argues, is not just that we lack information about bats; it is that the very idea of a "bat's point of view" resists the objective conception. We can adopt an objective standpoint toward ourselves, but we cannot step outside all standpoints and include the subjective character of experience in a neutral description — because subjective character is essentially tied to a particular type of subject.

The critics respond in several ways. Reductionist physicalists argue that Nagel underestimates the progress of science: "what it is like" facts may turn out to be physical facts described from a different perspective, just as the "what it is like" of a computer simulation is nothing over and above its implementation. Functionalists argue that if consciousness is functional, then a complete functional description does include everything there is. Others argue that Nagel's argument proves only an epistemic limitation — we cannot imagine the bat's experience — not an ontological gap: there may be no extra facts, only facts we cannot represent. Illusionists argue that "what it is like" is a confused concept, and the hard problem dissolves once the concept is clarified. Defenders of Nagel reply that the subjective character of experience is the one thing we know most directly, and that a theory which denies it has denied the datum.

The essay's lasting contribution is that it set the terms of the debate: any adequate theory of consciousness must either explain subjective character or explain it away, and Nagel made clear just how deep the first option is.

Contemporary Relevance

"What Is It Like to Be a Bat?" remains the touchstone of the consciousness debate. It is the reference point for the hard problem (Chalmers explicitly builds on Nagel's notion of subjective character), for the knowledge argument, for the explanatory gap, and for the modern debate about whether the science of consciousness can ever be complete. The essay's question — is there something it is like to be a bat? — generalizes directly to AI: is there something it is like to be a chatbot, a self-driving car, or a future artificial general intelligence? Nagel's argument suggests that no functional or behavioral test, however sophisticated, can settle the question, because the subjective character of experience is not the kind of thing that appears in objective descriptions. The bat has thus become the emblem of the deepest unresolved problem about minds: what it is like to be anything at all.

Related Concepts

• Phenomenal consciousness: the subjective character Nagel defines.
• Mary's room: the knowledge argument that extends Nagel's conclusion.
• The explanatory gap: the gap between objective and subjective descriptions.
• The hard problem vs easy problems: why subjective character is hard to explain.
• Qualia: the individual phenomenal characters of experience.

Further Learning

• Thomas Nagel, "What Is It Like to Be a Bat?," Philosophical Review 83 (1974).
• Stanford Encyclopedia of Philosophy: Consciousness
• Internet Encyclopedia of Philosophy: Qualia
• Thomas Nagel, The View from Nowhere (Oxford University Press, 1986).