Can you see your shadow? That would require a point light source and looking in the right direction. It is easier for other people to see your shadow. Can you extend this concept beyond visible light and optics? You could think of your shadow as your unlived life and unresolved issues. You can see these things in other people, how it affects their behavior and how they project their biases and rigid thinking onto others. It is harder to see in yourself. You could conclude from inference that if everyone else has a shadow then you do too. Acknowledging your shadow is the first step in dealing with it.
Related Resources:How to Hear God's Voice!