What Is it Like to Be a Bat?

"What is it like to be a bat?" is a paper by 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. He argued that an organism had conscious mental states, "if and only if there is something that it is like to be that organism—something it is like for the organism."Daniel Dennett, a critic of Nagel's argument, nevertheless called this paper "the most widely cited and influential thought experiment about consciousness."

The thesis attempts to refute 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.

Nagel begins by arguing that the conscious experience is widespread, present 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" are unique. Nagel stated, “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.”

The paper argues that the subjective nature of consciousness undermines any attempt to explain consciousness via objective, reductionist means. A subjective character of experience cannot be explained by a system 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. Thus for consciousness to be explained from a reductionist stance, the idea of the subjective character of experience would have to be discarded, which is absurd. Neither can a physicalist view, because in such a world 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. Nagel argues that each and every subjective experience is connected with a “single point of view,” making it unfeasible to consider any conscious experience as “objective”.

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