How can we account for the existence of subjective experience within an objective physical universe?
This problem is a modern version of the mind/body problem; i.e. what is the relationship between the mind and the body? Are they separate entities, or are they somehow different aspects of the same thing? The question was posed in Nagel’s 1974 essay ‘What Is It Like to Be a Bat?’ and has been somewhat revitalised recently in the guise of Chalmers’s ‘hard problem’ of consciousness (Chalmers, 1995). Nagel argues that although we may understand the way bats use sonar to perceive their world, to fly and catch insects, we will never know what it is like to be a bat using sonar, precisely because we are not bats. Our understanding of bat sonar can only be a physiological and functional account; we will only ever have a view of bat sonar from the outside. Imagine what sonar must feel like inside, to a bat! In the same way that there is something it is like for us to see the world using our eyes (i.e. colours, hue and depth in our visual field), surely there must also be something it is like f
