The Meaning of Monogenēs as an Ordinary Greek Word—According to the Church Fathers
I begin by observing that Giles says the church fathers took μονογενής to mean “unique” “as we would expect if modern discussion on the meaning of this word are correct.” But as Giles acknowledges, this is “modern discussion.” Why would we expect the church fathers to follow a modern scholarly assessment of an ancient Greek word? It wasn’t until the late 19th century (B. F. Westcott) and mid-20th century (Francis Marion Warden and Dale Moody) that scholars began to question the translation “only begotten” in the New Testament. More recently Gerard Pendrick has done so in a significant 1995 article published in New Testament Studies. Prior to the late 19th century, at least since the time of Jerome and even earlier, the term in its five Johannine instances was rendered into Latin as unigenitus (“only begotten”). Even the revisionist scholars (Westcott, Warden, and Moody) admitted that at least in the fourth-century church fathers, if not by the Council of Nicaea (325) definitely by the First Council of Constantinople (381), the term μονογενής began to take on the meaning “only begotten” in Greek patristic literature. Pendrick thinks the shift from “unique” to “only begotten” began much earlier, in the writings of the second century apologists. Just because most modern scholars think μονογενής meant “unique” in extra-biblical Greek prior to the New Testament and in the New Testament itself, that does not warrant the assumption that that is what it meant for Athanasius and the Cappadocian fathers. This is just an initial observation that doesn’t prove Giles wrong, but it throws doubt on his working assumption.
But let’s dig in and see what the Greek-speaking church fathers actually said they believed was the meaning of μονογενής. We don’t have to speculate. They explicitly addressed the question. Now, they may be wrong in their own assessment of their language. That’s not out of the realm of possibility. Native speakers sometimes misunderstand their own language, especially if they have an agenda, and the church fathers certainly had an agenda. But we aren’t addressing the meaning of μονογενής in Greek. We are addressing what the church fathers thought it meant.
Well, the Greek-speaking church fathers routinely defined the term as meaning “only begotten” with the implication of having no siblings. When they said this, they even made it clear that they were referring to “common usage” apart from its specialized use in Trinitarian discourse. For example, here is what Basil of Caesarea says about the term:
“In common usage μονογενής does not designate the one who comes from only one person [as the Arian Eunomius wanted to argue], but the one who is the only one begotten (ὁ μόνος γεννηθείς) …. If your [Eunomius’s] opinions were to prevail, it would be necessary for the entire world to re-learn this term, that the name ‘only-begotten’ does not indicate a lack of siblings but the absence of a pair of procreators” (Basil, Against Eunomius 2.20-21; PG 29.616-17; FoC 122, pp. 159, 161).
It should not go unnoticed that Basil and Eunomius agreed that the -γενης stem means “begotten.” Their disagreement was over the meaning of the μονο- stem. Eunomius wanted to take it to mean “of one” so that μονογενής would then mean “begotten from only one person.” But Basil said “the entire world” knows μονογενής means “the only one begotten,” with the implication that the person so designated has no siblings.
The church fathers understood the word μονογενής, as an ordinary Greek word, as involving notions of “begetting,” “procreation,” and “offspring.” It didn’t just mean “unique” but “only child.” This can be seen in their analysis of two contrasting biblical titles for Christ, μονογενής (“only begotten”) and πρωτότοκος (“firstborn”). The church fathers thought μονογενής carried the implication of not having any siblings, and as therefore contradictory with the term πρωτότοκος, which does imply siblings because the firstborn is first in a series. The two terms are contradictory because you can’t be both “only begotten” and “firstborn.” If you are the firstborn, that means you have siblings, and therefore you aren’t an only child. Here are two quotes where the church fathers say just that:
“The term μονογενής is used where there are no brethren, but πρωτότοκος because of brethren” (Athanasius, Against the Arians 2.62; NPNF2 4.382).
“Who does not know how great is the difference in signification between the term μονογενής and πρωτότοκος? For πρωτότοκος implies brethren, and μονογενής implies that there are no other brethren. Thus the πρωτότοκος is not μονογενής, for certainly πρωτότοκος is the first-born among brethren, while he who is μονογενής has no brother; for if he were numbered among brethren he would not be only-begotten” (Gregory of Nyssa, Against Eunomius 2.7-8; NPNF2 5.112; Refutatio confessionis Eunomii §76 in Gregorii Nysseni Opera, vol. 2, ed. Jaeger [Leiden: Brill, 1960]).
Of course, the New Testament does apply both terms to Christ, so the church fathers had to deal with this apparent contradiction. They resolved it by arguing that the term μονογενής (“only begotten”) is applicable to the Son absolutely, as he is in himself, apart from creation and new creation, while the title πρωτότοκος (“firstborn”) is applicable to the Son relatively, as the “firstborn of all creation” (Col 1:15), “the firstborn from the dead” (Col 1:18), “the firstborn among many brethren” (Rom 8:29), that is, as he exists, not absolutely and immanently, but in relation to creation and new creation. This argument is made by Athanasius (Against the Arians 2.62-64; NPNF2 4.382-83) and Gregory of Nyssa (On Christian Perfection to the Monk Olympios, in Gregorii Nysseni Opera, vol. 8.1, ed. Jaeger [Leiden: Brill, 1963], pp. 200-202).
But the point at present is not how they resolved the apparent contradiction, but the fact that they thought it was an apparent contradiction in the first place. The apparent contradiction arose from what to them were the lexical realities of the meanings of these two words: μονογενής (“only begotten”) and πρωτότοκος (“firstborn”).