Sizing up Consciousness: Towards an objective measure of the capacity for experience

Everyone knows what consciousness is: it is what vanishes when we fall into dreamless sleep and reappears when we wake up or when we dream. However, we become less and less confident when we are called to answer fundamental questions about the relationships between consciousness and the physical world. Why is the cerebral cortex associated with consciousness, but not the liver, the heart, the cerebellum or other neural structures? Why does consciousness fade during deep sleep, while cortica...