Recently Charles Lee Irons posted on TGC a defence of the translation of μονογενής in the New Testament as “only-begotten”, instead of the modern consensus that it means “unique” or “one of a kind”. Why? I can only presume, and the article indicates as much, that it’s in response to the ongoing controversy in Evanglical circles over Grudem and Ware’s “Eternal Relations of Authority and Submission” (ERAS) and problems with Eternal Generation (EG). One should also look at Daniel Wallace’s musings in response.
Grudem, as I hear it, has affirmed EG at the recent ETS conference, but without retracting his position on ERAS. I wasn’t there, so I don’t know what he has said most recently.
Nonetheless, if you go back to Grudem’s Systematic Theology, he makes a clear case *against* EG in Appendix 6. He basically states that μονογενής derives from μονός and γενός rather than μονός and γεννάω. He also states that it as misunderstood, to mean ‘only-begotten’, and that this is the erroneous usage found in the Nicene Creed.
Grudem also states, erroneously, that the Greek Fathers should have used μονογέννητος! (One should exercise more caution in telling Greek theologians how to use their own language)
Let me quote Grudem at length:
If the phrases “begotten of the Father before all worlds” and “begotten, not made” were not in the Nicene Creed, the phrase would only be of historical interest to us now, and there would be no need to talk of any doctrine of the “eternal begetting of the Son.” But since the phrase remains in a creed that is still commonly used, we perpetuate the unfortunate necessity of having to explain to every new generation of Christians that “begotten of the Father” has nothing to do with any other English sense of the word beget. It would seem more helpful if the language of “eternal begetting of the Son” (also called the “eternal generation of the Son”) were not retained in any modern theological formulations. Similarly, to refer to Jesus as God’s “only begotten” Son—language that derives from the King James translation—seems to be more confusing than helpful. What is needed is simply that we insist on eternal personal differences in the relationship between Father, Son, and Holy Spirit, and that the Son eternally relates to the Father as a son does to his father.
The main problem with Grudem’s view is that the pro-Nicene articulation of the doctrine of Eternal Generation does not depend upon how they read μονογενής. And this is why Irons’ article is chasing a red herring – you don’t need to defend μονογενής as “only-begotten” to defend EG.
When Grudem says that ‘eternal begetting’ means we have to keep re-explaining what ‘beget’ means in this context, this is no different than the pro-Nicenes in the fourth century. They have to continually say that the relationship of ‘generation’, i.e. that the Father is father to the Son, and the Son is son to the Father, does mean that (a) they are of the same essence, and (b) that the Son’s origin is in the Father in a causal sense, but that it doesn’t mean there is any temporal beginning to the Son, change or diminishment in the Father, difference in essence of the Son, or materiality or even sexual intercourse involved in the Son’s coming into being.
That is, for the Father-Son language of the Scriptures, the pro-Nicenes articulate how the analogy works – what parts are actually analogous, and what parts are not analogous. All good analogies work by providing a comparison between two things, but two things that are alike in every respect are in fact the same thing! Saying that an apple is analogous to an apple is true, but unhelpful. Analogy works when something is alike in a pertinent respect, and unlike in other respects. That’s why a careful use of analogy distinguishes its points of analogy, and its points of disanalogy.
Does μονογενής mean ‘only-begotten’ in the New Testament in the sense the fourth century Fathers understand it? I don’t think so. I actually don’t want to go down that linguistic path today, but my point is that it doesn’t matter for Eternal Generation of the Son. It’s similar to, though perhaps more contentious than, the fact that Hebrews 1:3 uses the word ὑπόστασις in a way totally uninformed by late fourth century discussions of God existing in three ὑποστάσεις. The fourth-century pro-Nicenes are “free” to use μονογενής to mean only-begotten in the context of their debates, without having to either import that meaning back into the New Testament texts, or us thinking that their articulation of Nicene Trinitarianism depends upon such a reading being present in those texts.
It’s certainly true, I should say, that those same pro-Nicenes make arguments from those Johannine verses; it’s also true that the pro-Nicene arguments are exegetically propelled. But in this case, understanding μονογενής as “unique” does no harm to this position. Though thinking that understanding μονογενής as “unique” was an argument for rejecting Eternal Generation does great harm to orthodox trinitarianism (and is one reason Grudem was wrong).
 Wayne A. Grudem, Systematic Theology: An Introduction to Biblical Doctrine (Leicester, England; Grand Rapids, MI: Inter-Varsity Press; Zondervan Pub. House, 2004), 1234.