CONCEPT
What Is It Like to Be a Bat?
Nagel’s 1974 formulation of the subjective character of consciousness—that an organism is conscious if and only if there is something it is like to be that organism from the inside—the most precise statement of what is at stake in the question of machine consciousness and why behavioral evidence cannot settle it.
A being is conscious,
Thomas Nagel proposed in his 1974 paper, if and only if there is something it is like to be that being—something it is like
for that being, from the inside. The phrase does precise work. It names not a behavior, not a capability, not a functional state, but a felt interior: a point of view, a subject for whom experiences exist rather than merely being undergone. The bat was chosen because it is plainly conscious—it is a mammal, it has a nervous system, it navigates and hunts with evident purpose—and yet its primary mode of perceiving the world, echolocation, is so alien to us that we cannot imagine our way into it. We can know everything about bat neurophysiology, map every neural pathway, and still not know what it is like to be the bat, because