<human>:  Where does the author say that the human brain is a “spiritual machine” in the book ‘The Age of Spiritual Machines?
<bot>: The author says that the brain is a “spiritual machine” in Chapter 2, pg. 58. The author describes the brain as a “spiritual machine” because it is a physical system that can do things that are not possible for a purely physical system. For example, the brain can store and retrieve memories.