The word light, like many words in scripture, are used synonymously to create a variety of ideas. Just because we see Jesus represented
as light
in John 1, and other places as well, does not mean that every time we see this word in scripture we are free to infer that it has to automatically refer to Jesus. Light is also used to symbolize truth and moral uprightness. In the same way, darkness us used to symbolize intellectual blindness and in John 1. There is no legitimate hermeneutical principle that can justify defining the light in Gen 1 as Jesus. Gen 1 is describing the creation of the material universe of which natural light was a part in verse three. It is only one's insistence that natural light cannot exist apart from the sun that would bring one to insist the light of verse three must be something other than natural light that is composed of matter and energy.