Hi Willy,
My intention was certainly not to trigger any "it's too complicated don't think about it" programming, but the simplicity of the Gospel of John, and even the letter from Clement of Rome to the Corinthians, is in stark contrast to the Greek philosophy that shaped later Christian doctrine. Ask yourself, what do Clement of Alexandria, Origen, Arius, Alexander of Alexandria and Athanasius have in common? They were all from Alexandria, a leading centre for the study of Platonism and home of the Jewish philosopher Philo.
How did this happen? It started with the Apologists (Aristides, Justin Martyr, Athenagoras, Tatian, Theophilus of Antioch) who wished to present Christianity to the culture of their day in such a way as to defend it against the charge of atheism. To the educated classes, they insisted that the truth of Christianity is that to which the pagan philosophers pointed. To do this they employed the concept of the Logos which was already known to both Judaism and Stoicism. According to the Apologists, Christ is the Logos, preexistent before the incarnation as the Father's mind or thought. They used the Stoic distinction between the Logos endiathetos (the immanent Word) and the Logos prophorikos (the expressed Word) to describe Christ's unity with the Father and his manifestation. Thereafter philosophy (and pragmatism) ruled and scripture was employed to support it.
One of the more contentious expressions used in the Nicene Creed was that the Son was homoousios (of one substance) with the Father. After Constantine's death a number of councils were held that tried to omit the phrase homoousios, many preferring homoiousios (of like substance) to describe the relationship, because homoousios could mean they were the same (which, you say, is not a Trinitarian teaching at all). How did they reach agreement? A coalition of moderates known as the Homoiousians taught that the Godhead exists simultaneously in three modes of being or hypostases. All three have one nature, God. To describe how the one substance can be present at the same time in three, the analogy of a universal and its particulars is used. The difference between ousia (substance) and hypostasis (being) is the difference between universal and particular. Each hypostasis of the Godhead is set by its appropriate characteristics, just a each man represents the universal man. This understanding allowed the Eastern church to interpret homoousios (of one substance) in the light of homoiousios (of like substance), and a more acceptable doctrine was agreed at the Council of Constantinople in 381.
So, having given some thought to this complicated doctrine you may understand better why I contrasted such philosophy with the simplicity of scripture. The fact is that their use of homoousios allowed those who believed they were of the same substance (tautoousios) to interpret it that way, and those who believed they were of like substance (homoiousios) to interpret it that way. Everyone went home thinking they had won the day. The winner, alas, was obfuscation and pragmatism, not truth.
Earnest
"Beware the Jubjub bird, and shun the frumious Bandersnatch!" - Rev. Charles Dodgson