PBS's Scientific American Frontiers profiles the author of my favorite books on philosophy of mind, free will and evolution, Daniel C. Dennett.

Renowned philosopher Dr. Daniel C. Dennett enjoys getting to the bottom of some of life's biggest questions; where did we come from, and what makes us human? His search for the answers has led him down some unexpected paths. The author of several books, including "Consciousness Explained" and "Darwin's Dangerous Idea," Dennett sat down recently with Alan Alda.