To continue with 'Misquoting Jesus', the author gives examples of two triads of reasons why the text of the New Testament was modified. The first triad is in the chapter entitled 'Theologically Motivated Alterations of the Text', and he gives examples of the way the text was modified by "proto-orthodox" copiers both before Christianity achieved state power (when the copyists were amateurs) and after (when they were professional scribes). The three 'heresies' which led the orthodox to falsify the text of the Bible that Ehrman mentions are 1)the "adoptionists" who believed that Jesus was not really "the Son of God" but rather was "adopted" by God as his son. I don't know if any of the Eastern Churches presently hold this view, but it would be interesting to see how close they come. The ancient example were the Judeo-Christian sect known as the Ebionites. and 2)The Docetists, the precise opposite of the adoptionists in that they believed that Jesus was NOT a flesh and blood human (unlike the adoptionists who believed that he was ONLY such), but rather that his humanity was mere appearance. The most prominent Docetist was a man named Marcion whom a lot of the "church fathers" polemicized against. The final 'heresy" were the "separatists" who, unlike the above two schools held that Jesus had indeed BOTH natures-human and divine- but that they were totally SEPARATE, and that the Divine nature infused the human nature of Jesus and later abandoned it at the time of the crucifixion. Only to later resurrect the human Jesus.
All of these heresies were actually more rational, in my opinion, than the later trinitarian doctrine that became Christian orthodoxy. The author gives a number of examples of where the text of the NT was modified to accord with the polemics of the orthodox.
More on non-theological reasons for text modification in the next post.