Host: Indre Viskotnas

Despite our individual differences, highlighted especially during an election, much of what we see, hear, smell or feel is shareable: that is, when standing in front of an object, we can more or less agree that it has a particular color, shape, texture, size and so on. But what if I tell you that I see an object clearly which you do not? Or hear a voice that doesn't have a physical source? Now we enter the world of hallucinations.

Hallucinations, or perceptions of objects without an external reality, are not confined to the minds of people with schizophrenia or those who take hallucinogenic drugs. In many cultures, visions are considered a privileged state of consciousness; the trait of a special person chosen by some supernatural force to pass along an important message. But in our western worldview, hallucinations are often associated with a malfunctioning brain. What causes the startling, unbidden perception of something that seems very real, but has no material existence outside of our own minds?

With reference to his own mind-altering experiences, the 'poet-laureate of medicine', Dr. Oliver Sacks, takes us through the looking glass and into the fascinating world of hallucinations.

Oliver Sacks, M.D. is a physician, a best-selling author, and a professor of neurology at the NYU School of Medicine.

He is best known for his collections of neurological case histories, including The Man who Mistook his Wife for a Hat (1985), Musicophilia: Tales of Music and the Brain (2007) and The Mind's Eye (2010). Awakenings (1973), his book about a group of patients who had survived the great encephalitis lethargica epidemic of the early twentieth century, inspired the 1990 Academy Award-nominated feature film starring Robert De Niro and Robin Williams.

Dr. Sacks is a frequent contributor to the New Yorker and the New York Review of Books, and a fellow of the American Academy of Arts and Letters as well as the American Academy of Arts and Sciences. His new book, Hallucinations (2012), has just been released.