Carl Zimmer has a nice piece in the New York Times on Neuroscientist Giulio Tononi’s quest to “quantify” consciousness. Zimmer writes,
Consciousness, Dr. Tononi says, is nothing more than integrated information. Information theorists measure the amount of information in a computer file or a cellphone call in bits, and Dr. Tononi argues that we could, in theory, measure consciousness in bits as well. When we are wide awake, our consciousness contains more bits than when we are asleep.
[I look forward to buying a "Consciometer" in 2050 - Imagine...when you're sharp you measure 9.5 consciousness-units. When you space out and grab a hot pan on the stove you're floating around 4.8 units. Sleep is zero, and daydreaming is 3].