Altered states of consciousness are nonnormal states of mental awareness or experiences. These include dreams, hallucinations, induced mental alterations such as by meditation, alcohol, drugs or disease. What can altered states of consciousness tell us about the essence of consciousness itself?

Free access to Closer to Truth's library of 5,000 videos: http://bit.ly/376lkKN

Watch more interviews on altered states of consciousness: https://bit.ly/37K0Ryj

Patrick McNamara is Director of the Evolutionary Neurobehavior Laboratory in the Department of Neurology at the BU School of Medicine and the VA New England HealthCare System.

Register for free at CTT.com for subscriberonly exclusives: http://bit.ly/2GXmFsP

Closer to Truth presents the world’s greatest thinkers exploring humanity’s deepest questions. Discover fundamental issues of existence. Engage new and diverse ways of thinking. Appreciate intense debates. Share your own opinions. Seek your own answers.