The light shines in the darkness, and the darkness did not overcome it. (John 1:5)
A lot of people believe God doesn’t exist, that God is only a fanciful projection of our minds. That is their choice. But their disbelief does not mean that God does not exist. Some Jews in hiding from the Nazis in World War II wrote on a cellar wall in Cologne the following inscription. “I believe in the sun, even when it is not shining. I believe in love, even when not feeling it. I believe in God, even when God is silent.”
When John says Jesus is the Light of the World, he refers to the divine illumination of a person’s mind and conscience. This light dispels human darkness and continues throughout time. The word Life refers to the function of the Holy Spirit that represents the positive aspects of life and existence. Life represents the authentic existence God wants us to have. Life and salvation are associated with light.
Darkness is symbolic of disbelief as well as total evil that cannot overcome the Word. Jesus comes into the world as a human being to have a flesh and blood relationship with us. Jesus partially reveals to us the mind of God. As the Word, Jesus brings light into our midst to dispel the darkness; but many turn their backs on the light.
Walking on Water: Skeptics and Believers Discuss Whether Jesus Matters, pages 148 & 47.