A drunk was crawling about on the sidewalk under a lamppost at night.

A Police Officer came up to him and inquired, "What are you doing?"

The drunk replied, "I'm looking for my car keys."

The Officer looked around in the lamplight, then asked the drunk, "I don't see any car keys. 
Are you sure you lost them here?"

The drunk replied, "No, I lost them over there", and pointed to an area of the sidewalk 
deep in shadow.

The policeman then asked, "Well, if you lost them over there, why are you looking over here?"

The drunk looked at him and said, "Because the light is better over here."