In the bible, what does it mean 'what does light have to do with darkness'?

We know that God is light, and if God is all knowledge, then we can understand that full darkness knows only lies. Knowing only lies is knowing less than nothing. So where would zero knowledge be on the Gray-scale, would it be fully black, or gray? In real life, is innocence zero knowledge? Notice that Adam and Eve who did not have the knowledge of Good and evil, light and darkness, truth and lies where considered innocent, until they ate of the tree and gained knowledge ...