According to Wikipedia, this is the concept:
Originally Posted by wiki
In a nutshell the concept behind the songs was to document the different points on a path to self-realization. In our interpretation of this journey, the wanderer ends up essentially in the same place that he or she began, if not humbled and even more overwhelmed. In a sense the ending is somewhat tragic, but without experiencing all of the lows how can anyone ever appreciate the amazing subtleties that this world has to offer? And so, if the search for beauty and understanding is cyclical and unending, then at least we'll never stop experiencing the thrill of the hunt...