An idea is held to be true when it turns out to be useful and good, when it serves its purpose in making life better at that moment and for that individual.
One saw this phenomenon in the nineteenth-century age of the transcendentalists, and one sees it today in the age of Oprah. What is most absolute is not truth and falsehood, virtue and vice; what matters most absolutely is the advancing self. The individual is perpetually moving toward wholeness and completion, and ideas are adopted as they suit that mission. Individual betterment is the center around which the entire universe revolves.
This is a brutal form of narcissism. The weight of the universe is placed on the shoulders of the individual. Accordingly, in modern American culture, the self becomes semidivinized. People feel free to pick and choose their own religious beliefs, because whatever serves the self-journey toward happiness must be godly and true.
This means that each individual must be the locus of values. It means that the central question of life is not “What does God command and love?” but rather “What is my destiny and fulfillment?” It is not our duty to humbly obey God’s law and submit to the universal order. It is our duty to create and explore our self, to realize our own inner light. It is up to each of us to justify our own existence.