Christof Koch is a German-American neurophysiologist and computational neuroscientist best known for his work on the neural basis of consciousness. He is the president and chief scientist of the Allen Institute for Brain Science in Seattle. From 1986 until 2013, he was a professor at the California Institute of Technology.   Tao and Christof sit down at the tail end of an 8 day conference on the neuroscience of consciousness held on the island of San Servolo, off the coast of Venice, Italy.