Why is your shadow proportional to your shadow

The very existence of a shadow is dependent on light. the rock group with the title ( Shadows of Knight) was something of a contradiction though they meant an armored warrior. In other words a certain amount of light is required to produce a shadow. This knocks out a number of popular stories of someone walking home in (always) deserted or poorly lighted streets being guided by a shadow. analyze the facts it does not work out! In astronomy- an object at the zenith- ninety degrees elevation- or Twelve O'clock high- does not cast a shadow. there are a number of technical factors of interest to artists and photographers.. but I cannot get into them in this narrow compass.