In my previous post, Where is Asia?, I wrote how Asia was an artificial construct made by the Greeks to describe the lands and people east of them. And how today what we consider Europe, Africa, and Asia actually spill into each other.
Other geographers feel that continents are a flawed way of studying and examining the world. Dr. Harm de Blij uses "geographic realms" in his textbooks books. These realms are lands of similar cultural traits and physical landforms.
Continents are a good starting point for learning about the world but as one advances one quickly realizes that the physical and cultural landscape is so much more interrelated and complex than first imagined.