Book excerpt: Disillusionment with psychology is leading more and more people to formal philosophy for clues about how to think about life. But most of us who try to grapple with concepts such as reality, truth, common sense, consciousness, and society lack the rigorous training to discuss them with any confidence. John Searle brings these notions down from their abstract heights to the terra firma of real-world understanding, so that those with no knowledge of philosophy can understand how these principles play out in our everyday lives. The author stresses that there is a real world out there to deal with, and condemns the belief that the reality of our world is dependent on our perception of it.