It began with the victory of Augustinian Neo-Platonism, in the 5th century. The consequence of this has left today’s Christianity thinking that the goal of a person life is to make it into heaven, rather than to become united to God in body & soul now and after this life. The long term consequence of this is a two story universe, God up stairs, & us downstairs, and our task should we choose to accept it, is to make it upstairs.
This distortion continued in the 10th & 11th century by the additions of St Anselm. By way of his orientation towards legal satisfaction, what we now have is a Christianity that is most of all concerned with how man gets off the hook for sin on light of its insult of God’s honor. Christianity lost its focus on why and how God restores humanity to our original design as Christ’s icon on earth.
Move forward to the 12th & 13th century and we find the influences of St Aquinas. His influence made Christianity something that must be explainable and definable at every point, in other words, scholastic. For many Christians today, there is no higher form of Christianity than intellectual Christianity. This is a faith that lives in the mind.
Move forward again to the protestant reformation of the 16th century, and there the west received the same authority that prior to it belonged to bishops and popes. Every individual became the protector of the faith, with the authority to keep, shed, or redesign the articles of faith as each saw fit according to their understanding of the bible.
Go forward again to the 18th century and find the great awakening; this movement in the
Couple this with the need to feel moral and aligned to God, the social Victorian moralism made its way into Christianity. This moralism shaped the faith into more than just something in the mind and a one time experience. However, the problem here is that there was a focus on a few select sins such as sexual concupiscence, drunkenness, and participation in the things enjoyed by the general culture.
To sum this all up; what we have in the west today is a faith that is dualistic, legal, intellectual, individualistic, based on a one time experience, and sustained by a biased moralism that focuses on avoiding a few specific sins. In short, the trajectory of the western faith has left us with a faith that has almost no relationship to the faith of the early church, and especially its mystical practices of transformation into Christlikeness.