What Is it Like to Be a Bat?

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"What is it like to be a bat?" is an influential 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 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] Nagel's example has been called "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. Reductionism is the philosophical position that a complex system is nothing more than the sum of its parts. For example, a physicalist reductionist approach to the mind states that all mental processes could be fully described if all the physical processes in brains and bodies were fully described. [4]

The paper starts with the idea of consciousness. Nagel argues that the conscious experience is very widespread and exists in most areas of animal life, especially in the mammalian subgroup. For an organism to hold the conscious experience it must be special. Special in the sense that only it can experience something or as Nagel says “an organism has conscious mental states if and only if there is something that is to be that organism- something it is like for the organism.”[5] That means that there is something special in terms of perspective that each individual organism experiences.

After defining the conscious experience, Nagel begins the process of developing his thesis. The idea that an organism has a special conscious experience that only it can have is what is called “the subjective character of experience”.[6] This is where the reductionist theory begins to fall apart. 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. That being said, for consciousness to be explained from a reductionist stance, they would have to leave out the idea of the subjective character of experience thus making their argument completely implausible because one cannot conduct an analysis and leave parts out. Just as a reductionist view cannot be used to explain consciousness neither can a physicalist view. This is because each phenomenal experience would have to have a physical property attached to it and that is almost impossible to do to a subjective character experience (physicalism). That would make it objective and Nagel argues that each subjective character experience is connected with a “single point of view”, making it unfeasible to be considered “objective”.

Subjective and objective concepts are two very different ideas, and this is when the metaphor of bats comes into play. Bats are mammals, and we are all to assume they have experience. Bats were chosen for this argument because they are highly evolved, active, and use a sensory apparatus which is different from many other organisms. Bats use very highly developed senses such as sonar and echolocation to detect things; this is similar to a human’s sense of vision, both of which are regarded as perceptional experiences. Perception is the hardest concept in this. As humans, we can imagine what it would be like to fly and hang upside down and eat bugs like a bat, but we are very limited because we are viewing this from our own perspective. Even when we imagine these things we are merely imagining what it would be like to behave like a bat and not actually be a bat. Granted this is an age in which science is very advanced and we have ways of simulating flying as well as ways to quantify sonar, and entomophagy is a not an uncommon human dietary practice, but nevertheless even with all of these advances and experiences we still do not know what it would be like to actually be a bat. Nagel states that even if we were able to gradually morph into a bat we would never actually experience that of a bat because our brains were not wired that way from birth therefore we would only be experiencing the life and behaviors of a bat but never the mindset.[7] This is the difference between subjective and objective points to Nagel. Subjectivity is said to be “our own mental activity is the only unquestionable fact of our experience”. This means 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 state. Objectivity can make sense of imagining what it is like to be a bat, but one cannot be completely unbiased because we are limited to only what we know. This in turn brings back the idea of subjectivity; we can only be sure of our own experiences.

Nagel ends his paper with the idea of physicalism. He goes on to state it would be wrong to assume that physicalism is incorrect, being that it is just a position that we have yet to truly understand. Yes, we understand that it states that mental states and events are just physical states and events, but we do not fundamentally know exactly how to clarify what exactly those physical states and events are. The last lines of the paper basically state that physicalism cannot yet be understood until we spend time actually understanding the true problem of objective and subjective, and, until then, we cannot even begin to conceive the mind-body problem.


Daniel Dennett denies Nagel's claim that the bat's consciousness is inaccessible to us, because 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. Many similar aspects of its experiences could be gleaned by further experiments.[3]:443

See also[edit]


  1. ^ "Thomas Nagel," in Ted Honderich (ed.). The Oxford Companion to Philosophy. Oxford University Press, 2010, p. 637.
  2. ^ Nagel, Thomas. "What Is It Like to Be a Bat?", The Philosophical Review, Vol. 83, No. 4 (Oct., 1974), pp. 435-450.
  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. ^ "Thomas Nagel," in Ted Honderich (ed.). The Oxford Companion to Philosophy. Oxford University Press, 2010, p. 637.
  6. ^ "Thomas Nagel," in Ted Honderich (ed.). The Oxford Companion to Philosophy. Oxford University Press, 2010, p. 637.
  7. ^ Helena De Preester, The deep bodily origins of the subjective perspective: Models and their problems, Consciousness and Cognition, Volume 16, Issue 3, September 2007, Pages 604-618, ISSN 1053-8100, http://dx.doi.org/10.1016/j.concog.2007.05.002. (http://www.sciencedirect.com/science/article/pii/S1053810007000372)

Further reading[edit]