Thomas Nagel points out in his 1974 paper “What Is It Like to Be a Bat?” consciousness can be observed only from the inside. A scientist can spend decades in a lab studying echolocation and the anatomical structure of bat brains and yet she will never know what it feels like, subjectively, to be a bat—or whether it feels like anything at all. Science requires a third-person perspective, but consciousness is experienced solely from the first-person point of view. In philosophy this is referred to as the problem of other minds.