There are several recurring thematic motifs on LOST, which generally have no direct impact on the story itself, but expand the show's literary and philosophical subtext. These elements include frequent appearances of the colors black and white, which reflect the dualism within characters and situations; eyes, which often appear in close-up at the start of episodes; dysfunctional family situations, as portrayed in the lives of nearly all the main characters; references to numerous works of literature, including mentions and discussions of particular novels. There are also many allusions to philosophy, demonstrated most clearly in the distinct naming of certain characters after famous historical thinkers, such as John Locke, Jean-Jacques Rousseau and David Hume.