As the fire moved, so did the shadow. As the works moved, so the shadow. But the shadow always turned, never constant. These opinions, mere shadows, were ready to change at any moment. They were not focused on the real issue or it's solution.
Public opinion changes as rapidly as a fire flickers.
Usually based on what ever feels good and makes one happy. The shadows easily change and have no real substance or foundation. Plato used this illustration to challenge the thinks and leaders of Athens to base their decisions on more then their opinion, something higher, something outside of themselves. To understand the true issues and source of life's shadows one must go to the fire, the source. The fire or source is an objective standard outside the observer.