I am convinced that an external objective physical world exists. It is a physical world that will continue to exist even if I or you are not around. This might be an unusual statement to say, but in the level of philosophical analysis, unusual arguments against common sense abound. Some people deny that there is an outside world. Technically, these people are called solipsists. They believe that nothing exists other than themselves. It is only their mind which truly exists. What seems like an outside world is only a reality constructed by their mind. They are alone in the deepest meaning of that word.