Michael Brant Shermer is an American science writer, historian of science, founder of The Skeptics Society, and Editor in Chief of its magazine Skeptic, which is largely devoted to investigating pseudoscientific and supernatural claims.

Shermer also engages in debates on topics pertaining to pseudoscience and religion in which he promulgates the need for scientific skepticism. Since April 2001, he has been a monthly columnist for Scientific American magazine with his Skeptic column. Shermer states he was once a fundamentalist Christian, but converted from a belief in God during his graduate studies, and has described himself as an agnostic, nontheist, atheist and advocate for humanist philosophy as well as the science of morality. He has expressed reservations about such labels, however, as he sees them being used in the service of "pigeonholing", and prefers to simply be called a skeptic.

He began his undergraduate studies at Pepperdine University, initially majoring in Christian theology, later switching to psychology. He completed his Bachelor's degree in psychology/biology at Pepperdine in and went on to study experimental psychology at California State University, Fullerton. Shermer completed his Master's degree from California State University in experimental psychology in 1978.

Shermer earned his PhD at Claremont Graduate University in history of science with his dissertation titled "Heretic-Scientist: Alfred Russel Wallace and the Evolution of Man: A Study on the Nature of Historical Change"). Shermer later based a full-length, 2002 book on his dissertation: In Darwin's Shadow: The Life and Science of Alfred Russel Wallace: A Biographical Study on the Psychology of History. Before starting the Skeptics Society, Shermer was an adjunct professor of the history of science at Occidental College, California. Since 2007, Shermer has been a senior research fellow at Claremont Graduate University. Since 2011, Shermer has been also an Adjunct Professor at Chapman University. In 1992 Shermer started the Skeptics Society, which produces Skeptic magazine and currently has over 55,000 members. In addition, the group organizes the Caltech Lecture Series which offers speakers on a wide range of topics relating to science, psychology, social issues, religion/atheism, skepticism, etc. Shermer is the author of a number of bestselling science books, including Why People Believe Weird Things, The Science of Good and Evil, The Believing Brain, and The Moral Arc.

Shermer has been a speaker at all three Beyond Belief events from 2006 to 2008. He has spoken at three TED Conferences and his talks have garnered over 5 million views, and in 2014 he made the TED "All Stars" team of the 50 most popular TED talkers in the event's 30 year history, as voted by past attendees. Shermer is a frequent guest on Skepticality, the official podcast of Skeptic. Shermer has debated Deepak Chopra on multiple occasions, including during their March 2010 appearance on the ABC News program Nightline. On August 21, 2010, Dr. Shermer was honored with an award recognizing his contributions in the skeptical field, from The IIG during its 10th Anniversary Gala.

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