One symbol used of God in the Bible is that he is “light” and that his word sheds light to the world. Then equivalently, the lack of God in one's life is equivalent to being in darkness. In 1 John 1:5 it says that in God there is no darkness at all. This suggests that in the symbol, among the world we can expect to see a mixture of light and dark, and that mixing can give a false sense of security to society as a whole.
In 1 John 1, the symbol of light for God is used. It defines light to represent God, and how people have a choice to be associated with him in that light.
1 John 1:5: This is the message which we have heard from him and announce to you, that God is light, and in him is no darkness at all. 6 If we say that we have fellowship with him and walk in the darkness, we lie, and don't tell the truth. 7 But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus Christ, his Son, cleanses us from all sin. WEB
Of course, this isn't talking about a physical light in the sense of electromagnetic radiation, but rather a spiritual light. The spiritual light isn't seen by the eyes, but rather the amount of light can be sensed by conscience.
By analogy though, light is one of the things we get used to, and take for granted the amount we get. A dimly-lit room may not feel so dim until a bright light is turned on.
Our society as a whole has experienced the spiritual light of God from his word that he has delivered. On the whole, people have some understanding that some things are right and wrong, and this can be represented by a measure of light in the world. An example is given of people being in the light,
1 John 2:8: Again, I write a new commandment to you, which is true in him and in you; because the darkness is passing away, and the true light already shines. 9 He who says he is in the light and hates his brother, is in the darkness even until now. 10 He who loves his brother remains in the light, and there is no occasion for stumbling in him. 11 But he who hates his brother is in the darkness, and walks in the darkness, and doesn't know where he is going, because the darkness has blinded his eyes. WEB
People understand some of this type of commandment, and a respect for other people has become part of the accepted morality of society. Many aspects of values have origins in the values of God, but in a relativist society that doesn't value God as a God, this light is more there by history and accident than by design.
With there being no longer being any definitive source of values moral standards in the west, they are just following a random path of what people on the whole are comfortable with. However, because of the remnants of light from light of God, people don't feel they are in this spiritual darkness, and so are comfortable that they know what is right and wrong.
People can feel that they are in a light and can see spiritually because of the dim candle that society is keeping going among the rest of the darkness. That dimness of the free-wheeling values of society is perhaps just enough to keep people from realising that they are missing out on the full light of God in whom there is no darkness at all.