Dreams, Darkness, and Consciousness
What is consciousness? Where does it go when we sleep? When we dream? Does consciousness need external stimuli—light, matter, a world—to be conscious of? Neuroscientist and sleep expert Giulio Tononi sheds light on these difficult questions.
Image: "The Sleeping Gypsy" by Henri Rousseau (via Wikimedia Commons); Recorded June 2010; Posted February 2011



































