What Is it Like to Be a Bat?

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"What is it like to be a bat?" is a paper by the American philosopher Thomas Nagel, first published in The Philosophical Review in October 1974, and later in Nagel's Mortal Questions (1979). In it, Nagel argues that materialist theories of mind omit the essential component of consciousness, namely that there is something that it is (or feels) like to be a particular conscious thing.[1] An organism has conscious mental states, he argues, "if and only if there is something that it is like to be that organism—something it is like for the organism."[2] Daniel Dennett called Nagel's example "The most widely cited and influential thought experiment about consciousness."[3]:441


"What is it like to be a bat?" is a complex argument geared at refuting reductionism (the philosophical position that a complex system is nothing more than the sum of its parts). For example, a physicalist reductionist's approach to the mind–body problem holds that the mental process humans experience as consciousness can be fully described via physical processes in the brain and body.[4]

Nagel begins by arguing that the conscious experience is widespread, existing in many animals (particularly mammals), and that for an organism to have a conscious experience it must be special, in the sense that its qualia or "subjective character of experience"[1] are unique. As Nagel puts it, “An organism has conscious mental states if and only if there is something that it is like to be that organism - something that it is like for the organism to be itself.”[1]

The paper proceeds to argue that the subjective nature of consciousness calls into question any attempt to explain consciousness via objective, reductionist means. A subjective character of experience cannot be explained by any systems of functional or intentional states. Consciousness cannot be explained without the subjective character of experience, and the subjective character of experience cannot be explained by a reductionist being; it is a mental phenomenon that cannot be reduced to materialism.[5] Thus for consciousness to be explained from a reductionist stance, the idea of the subjective character of experience would have to be disregarded, which is absurd. Just as a reductionist view cannot be used to explain consciousness, neither can a physicalist view, because in a physicalist view each phenomenal experience had by a conscious being would have to have a physical property attributed to it, which is impossible to prove due to the subjectivity of conscious experience. As Nagel argues, each and every subjective experience is connected with a “single point of view,” making it unfeasible to consider any conscious experience as “objective.”

Nagel uses the metaphor of bats to clarify the distinction between subjective and objective concepts. Bats are mammals, so they are assumed to have conscious experience. Nagel used bats for his argument because of their highly evolved and active use of a biological sensory apparatus that is significantly different from that of many other organisms. Bats use their very highly developed sense of echolocation to navigate and perceive objects within their environment. This method of perception is similar to the human sense of vision, and both sonar and vision are regarded as perceptional experiences. As humans, we can imagine what it would be like to fly, navigate by sonar, hang upside down and eat bugs like a bat, but our powers of imagination are limited because we cannot escape our subjective perspective as we attempt to imagine "objectively" the perspective of the bat. Nagel states that even if we were able to metamorphose gradually into bats, none of us would actually be able to experience consciousness as a bat because our brains would not have been wired as a bat's from birth; therefore, we would only be able to experience the life and behaviors of a bat, but never the mindset.[6]

Such is the difference between subjective and objective points of view to Nagel. According to him, “our own mental activity is the only unquestionable fact of our experience,” meaning that only we know what it is like to be ourselves (Subjectivism). Objectivity, on the other hand, is based on placing one's self in an unbiased, non-subjective state of perception. For Nagel, the objective perspective is unfeasible because we are limited to only what we know from our subjective experience. Thus, we can only be sure of our own experiences, our own subjectivity.

Nagel concludes with the contention that it would be wrong to assume, outright, that physicalism is incorrect, since it is just a position that we have yet to truly understand. Yes, we understand that according to physicalism, mental states and events result from physical states and events, but we do not fundamentally know exactly how to clarify what those physical states and events are. Nevertheless, he holds that physicalism cannot yet be understood until we take time to work on the problem of objective versus subjective experience. Until we can effectively and accurately clarify the objective/subjective distinction, we cannot even begin to conceive of the mind-body problem.


Daniel Dennett denies Nagel's claim that the bat's consciousness is inaccessible to us, contending that any "interesting or theoretically important" features of a bat's consciousness would be amenable to third-person observation.[3]:442 For instance, we already know that the bat wouldn't detect objects more than a few meters away because echolocation has a limited range. He holds that any similar aspects of its experiences could be gleaned by further scientific experiments.[3]:443

See also[edit]


  1. ^ a b c "Thomas Nagel," in Ted Honderich (ed.). The Oxford Companion to Philosophy. Oxford University Press, 2010, p. 637.
  2. ^ Nagel, Thomas (1974). "What Is It Like to Be a Bat?". The Philosophical Review 83 (4): 435–450. doi:10.2307/2183914. JSTOR 2183914. 
  3. ^ a b c Dennett, Daniel C. (1991). Consciousness Explained. Boston: Little, Brown and Company. 
  4. ^ Wimsatt, William C (1976). Reductionism, Levels of Organization, and the Mind-Body Problem. Springer US. pp. 205–267. ISBN 978-1-4684-2198-9. 
  5. ^ "Qualia | Internet Encyclopedia of Philosophy". www.iep.utm.edu. Retrieved 2015-06-01. 
  6. ^ De Preester, Helena (2007). "The deep bodily origins of the subjective perspective: Models and their problems". Consciousness and Cognition 16 (3): 604–618. doi:10.1016/j.concog.2007.05.002. 

Further reading[edit]