Thomas Nagel

American philosopher, born in Belgrade, University Professor emeritus at New York University. His essay 'What Is It Like to Be a Bat?' (1974) argued that an organism is conscious exactly when there is 'something that it is like to be that organism', and that this subjective character escapes any objective, physical description: no amount of knowledge about echolocation tells us what it is like for a bat. The formula became the standard way of picking out phenomenal consciousnessphenomenal consciousness, n.: The felt, experiential side of the mind — what it is like to taste coffee or to feel sad — as opposed to simply processing or reporting information., and the argument anticipated the hard problem of consciousnesshard problem of consciousness, n.: The puzzle of why physical processes in a brain — or a computer — should feel like anything from the inside, rather than simply running without any inner experience. and the knowledge argumentknowledge argument, n.: A thought experiment about Mary, a scientist who knows every physical fact about color but has lived all her life in a black-and-white room. When she first sees red, does she learn something new?. In AI debates it frames the question of whether there is anything it is like to be a machine, and why behavioral evidence may not settle it (see machine consciousnessmachine consciousness, n.: Whether a machine such as an AI system could have genuine experiences of its own — and the research field that tries to find out, or to build such a machine., problem of other mindsproblem of other minds, n.: The puzzle of how we can know that anyone besides ourselves has thoughts and feelings, since we only ever see their behavior. AI turns this old puzzle into a practical one.). His later books, from 'The View from Nowhere' (1986) to 'Mind and Cosmos' (2012), question whether materialist science can fully account for minds.