God is light and he is always present. You can correctly say that darkness exists where light is absent from the physics point of view. Spiritually speaking, we are in darkness only because we have shut our eyes so that we might not see the light of God. This is self-imposed imprisonment. To see it, we must open our eyes, turn to the Lord and ask him to liberate us. We all need to reach such a point in life if we ever hope to be saved.