"Why should we base the validity of all of our life's beliefs on a theory?" I'm not even sure what that question means, but the UC Berkeley student who asked it to Dr. White didn't look pleased by his fact-based answer.
From Wikipedia: Timothy Douglas White is an American paleoanthropologist and Professor of Integrative Biology at the University of California, Berkeley. He is most famous for his work on Lucy as Australopithecus afarensis with discoverer Donald Johanson.