What Is it Like to Be a Bat?
"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 is (or feels) like to be a particular conscious thing. 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." Nagel's example has been called "The most widely cited and influential thought experiment about consciousness".:441
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"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's approach to states of minds would be that all mental processes could be fully described if all the physical processes in brains and bodies were fully described.
The paper starts with the idea of consciousness. Nagel argues that the conscious experience is very widespread and could exist in most areas of animal life, especially in the mammalian subgroup. For an organism to have a conscious experience it must be special, in the sense that only it can have its specific conscious experience of something: “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.” Thus, there is something special in terms of perspective that each individual organism experiences.
After defining the conscious experience, Nagel develops 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”. 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.
That being said, for consciousness to be explained from a reductionist stance, the idea of the subjective character of experience would have to be disregarded, thus making the argument completely implausible (as one cannot conduct an analysis while leaving parts out of the said analysis). 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.”
Subjective and objective concepts are two very different ideas. This is where the metaphor of bats enters the argument. Bats are mammals, and, as such, 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, or biosonar, 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 and 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.
As we imagine what it would be like to be a bat, we can only imagine what it would be like to behave like a bat: we cannot actually be a bat. Granted, this is an age in which science is very advanced. We have ways of simulating flying as well as ways to quantify sonar. As well, 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 actually to be a 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.
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.: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.:443
- "Thomas Nagel," in Ted Honderich (ed.). The Oxford Companion to Philosophy. Oxford University Press, 2010, p. 637.
- Nagel, Thomas. "What Is It Like to Be a Bat?", The Philosophical Review, Vol. 83, No. 4 (Oct., 1974), pp. 435-450.
- Nagel, Thomas. "What is it like to be a bat?", Mortal Questions, Cambridge University Press, 1979, p. 166.
- Dennett, Daniel C. (1991). Consciousness Explained. Boston: Little, Brown and Company.
- Wimsatt, William C (1976). Reductionism, Levels of Organization, and the Mind-Body Problem. Springer US. pp. 205–267. ISBN 978-1-4684-2198-9.
- 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)
- Hacker, P.M.S. "Is there anything it is like to be a bat?", Philosophy 77, 2002, pp. 157–174.
- Nagel, Thomas. "What is it like to be a bat?" in Peter Alan Morton. A Historical Introduction to the Philosophy of Mind, Broadview Press, 1997, p. 391ff.