There is one God. There is one universe. There is one world. There is one truth. All of these former interrelate with one another. It's not as though anyone gets to work under other laws of nature. There isn't one set of laws of nature for one person and another set for someone else. We don't live out God's one book in some alternative universe. There isn't a separate will of God for certain people, while there is another for others, the first getting to have their own way in a manner that the other does not.
Where did Christianity start going down the wrong path, related in the first paragraph? Satan gave Eve an alternate choice in the garden. She could do something that God prohibited and still be OK. He tempted her with a liberty she didn't have. Satan justified what she would do contrary to God's prohibition. With that being settled, today's various iterations of two truths or two stories or two realms hearkens back to Constantine and then Augustine among others in early Roman Catholicism.
I mention Constantine, because he took his cue from a vision of a cross in the sky, a highly subjective experience that he attributed as God's direct revelation to himself in almost apostolic fashion. Then he proceeded to invent an unscriptural form of Christianity. Even before he became a Catholic type of Christian, Augustine loved Platonic philosophy. He brought Plato's philosophy into Christianity that bifurcated ideal truth from its concrete counterpart in the real world, the former the heavenly realm and the latter the earthly. These were his two cities in his City of God. The truth in the real world didn't necessarily match up with the truth of the ideal. The church could essentially disobey God on the ground, while fulfilling obedience in the other realm spiritually or mystically. When the Donatists confronted Augustine about the corruption in the church, he said that the true church was invisible and spiritual, bifurcating reality from the ideal. This was straight out of Plato.
Roman Catholicism spiritualized huge swaths of scripture through allegorization. This allowed all sorts of reading the personal and subjective into the text to allow for the Catholicism's own desired ends. Evangelicalism traces its origins from Roman Catholicism through Protestantism. Covenant theology defends amillennialism with a non-literal interpretation. This spiritualization allows for wide latitude in meaning that continues to exist in evangelicalism, bifurcating truth in numbers of different ways.
The Bible itself has been subjected to the bifurcation. You have the original manuscripts, an ideal text, and then we have what's in our hands, riddled with possible errors, and subject to the regular correction and tweaking of textual scientists. The originals are that subjective, mystical spiritual text, even an ideal, and the modern critical text, the concrete, scientific reality. Warfield saw a future danger in one truth, so he argued an original manuscript inerrancy, separated from the infallible apographa of preceding generations. In Augustinian fashion, a mystical Bible in the ideal with a less than perfect manifestation in the physical.
Theological liberalism rose in Germany from German Protestantism, an outgrowth of Augustinian Catholicism. These German theologians and philosophers idealized and spiritualized Jesus separate from a concrete, physical history. They took bifurcation to another iteration by separating the supernatural of scripture from the lower realm of science and relegating it to a spiritualized upper level, only representative of reality. Someone could receive Jesus without receiving His miracles.
Augustine's two cities found themselves in the ideal of a spiritual perfection of an invisible church and the less than perfect manifestation of every day life in a visible assembly. Unity could be found in a spiritual sense through the invisible church without doctrinal and practical agreement in real life. The bifurcation still counts this as unity. Then to match this in the real world, truth was bifurcated into essentials and non-essentials, not expecting agreement in the latter, because spiritual reality had already been attained. For whatever disunity there is, it still counts as unity, because it exists in a metaphysical ideal.
Bifurcation has affected the gospel of evangelicalism. You see the spiritual experience beginning with a profession that doesn't produce biblical change. At the some point in the future that higher life is reached through a process of succeeding crisis until someone is dedicated or surrenders to Jesus as Lord. Truth is divided into what can occur, the spiritual unity around the gospel, and then the practical, concrete, resultant behavior that would suggest obedience, but relegated to non-essential. This all is a later iteration of the spiritualization of Augustine.
This bifurcation of truth produces dual definitions of terms. Words can mean what someone wants in the upper, spiritualized, subjective story. Love can be toleration or sentimentalism. Grace can be license. Immodesty is nudity only. Rock music is now sacred. A word from God is what you might hear in your head, that you say was the Holy Spirit. And now marriage can be same sex. The terms become flexible outside of a scientific standing. The world in which they exist is also very pliable. In that world of imagination, few rules any longer apply.
Someone can live the Christian life without in fact living it. He's living it in a subjective, personal sense, that counts, because the truth has been separated from tangible, real world application. Anymore, someone can be a good Christian with hardly obeying the Bible. He's a good Christian.
Little can be criticized because the Bible can't be read one way. There are several ways to take everything, including the gospel. As a result, the primary ethic is acceptance. Non-acceptance is the new disunity. Obedience is accommodation. The conscience can't rightly function, because there is nothing to accuse, only to excuse.
No one can know if he is really saved or not really saved, because the basis of knowing has been rendered ambiguous by bifurcation. A person might have a story and a feeling. Another carries the card but rarely shows up. Some just punch the Christian time clock. You can't violate what you can't be sure about. It doesn't matter if you're sure because the upper realm is so subjective.
Anything can be justified through bifurcation of truth. More people can get along. The amillennialist does fine with the premillennialist, the pretribulationist with the post, the continuationist with cessationist, and the infant sprinkler with the credo-baptizer. None of the truth can matter enough with its spiritualization in an upper story. More people getting along results in a bigger crowd. The bigger crowd means that God must approve, so you're s success.
The one who won't fit in is the one who won't bifurcate truth. Mockery of him comes in concrete, real world terminology. He alone can be known to violate a standard. Without him, however, there is no hope for truth.