The end of John 1:4 further explains the life in the beginning part of the verse, in that it was the light of man or light possessed by or given to man. This too, can easily refer to the sustenance of human life, which Leon Morris brings forth when he said: “Just as light is the prerequisite condition for all earthly life, so Christ is the light, the very source of life, which is the condition of all human existence.”
All that being said, it’s important to note that both times the Light is mentioned in the first 10 verses of ch.1, there’s a response mentioned along with it. Clearly, no one can decide whether or not to receive physical life from Christ, since if someone exists, that person owes their creation and existence to the Word of God.
Interestingly enough John 8:12 also contains both concepts of light and life, along with the response—“I am the Light of the world; the one who follows Me will not walk in the darkness, but will have the Light of life.” Regarding this other referent to light, one commentator said: “He also is the source of [spiritual] light, since only those who possess eternal life have the capacity to ‘walk in the light,’ that is, to make moral decisions that are in accordance with God’s revealed will.”
So in one sense, every single person has received the light of life from the Son of God, but in another sense only his children, or those who believe (v.12), receive the fullest expression of the light of life. Therefore, since v.4 seems to function somewhat as a transition from v.3 to what’s upcoming in v.5, I’m not convinced we have to choose between the light and life of creation OR salvation. What’s of primary importance is to understand the significance of what John writes about the Word of God in v.4, in that every single evidence of life is meant to point to the eternal Word of God’s hand at work. Furthermore, each evidence of spiritual life from conversion to every step of the sanctification process is meant to give all the praise of glory to the eternal Word of God’s activity in salvation. It’s all from him and to him and for him.
 Leon Morris, Jesus is the Christ, p.203fn.  Andreas Kostenberger, BECNT, p.30.