'Light' is just pure being-ness; energy and awareness. When the light comes in contact with 'darkness' light forms can be created. God naturally becomes individual from a point of oneness. This is creation.
The world is actually in darkness because matter is finished energy. The only light is your own awareness...

Potential has to be zero; nothing; negative. Otherwise nothing particular could happen. Zero being a placeholder contains all other numbers. Light brings such digits into manifestation (awareness).