The pervading metaphor in this story, is, predictably, the clean, well-lighted place.  To Hemingway, it was much more than the physical darkness that frightened him-it was the symbolic darkness of reality.  Hemingway was a modernist, a realist, and a philosopher.  He believed the ultimate purpose of life was to discover such a clean, well-lighted place to escape from the darkness of the world-the dark truth that life is without truth or meaning

So light represents any device man uses to distract himself from the darkness.  The story's image of the lighted café in the sea of dark nothingness perfectly symbolizes Hemingway's nihilistic view of a world with no hope, no solace, no escape save that man creates for himself.