It is clear that Sahidic Coptic John 1:1 says that "the Word was a god." But it has been remarked that Coptic John 1:18 contradicts this, because this verse uses the Coptic definite article before the common noun, noute: p.noute, with reference to the Son.
But is this reference definitizing, equating the Son with God, or is it merely anaphoric, referencing "the" god of John 1:1c?
First, an important difference between John 1:1 and John 1:18 (in Coptic and in Greek) must be noted. John 1:1 reads the same in all extant ancient Greek and Coptic textual witnesses. But John 1:18 does not. John 1:18 does not possess the textual clarity of John 1:1c. John 1:18 is a text that has three significant variants in the Greek: monogenhs theos ("an only-[begotten] god"); ho monogenhs theos ("the only-[begotten] god"); and ho monogenhs huios ("the only-[begotten] son").
As a basically Alexandrian text, "the only-[begotten] god" would be expected in the Coptic version. That is, in fact, the reading of the Coptic Bohairic version: pimonogenes nnouti, which Horner renders as "the only-begotten God" in the main text and as "the divine only-begotten" in his footnotes. However, there was obviously some support among the Sahidic Coptic translators for the "only-[begotten] son" reading also, because they combined, or conflated, the two variant readings in the Sahidic Coptic version, giving us pnoute pShre nouwt , literally, "the god, the only son." (According to Jesus as Theos: A Textual Examination, by Brian James Wright, a similarly conflated Greek variant of John 1:18, ho monogenhs huios theos, was known to Ambrose, Irenaeus, and Origen.)
By putting the definite article here, the Sahidic Coptic translators mirror the Greek's ho monogenhs theos. But does this say the Word is God? No, for the Greek here can be translated simply, "the only-begotten god."
George Horner's English translation of the Sahidic Coptic renders pnoute pShre nouwt as "God, the only Son." But this is not what the Coptic says, this is merely Reverend Horner's English version of the Coptic, perhaps revealing his own theological presuppositions. The Coptic of this verse, John 1:18, can also be translated as "the god, the only son." The use of the Coptic definite article here does not demand the translation, "God." Particularly not when such a reading fails to correspond with the context and with what has already been stated at Coptic John 1:1 in both the Sahidic and the Bohairic versions: "the Word was a god."
Horner himself shows that not every instance of p.noute means "God," but may also mean "god," in context.
For example, at Acts 7:43, the Sahidic Coptic text has the definite article bound to the word for god, p.noute. Does Horner arbitrarily translate it as "God"? Not at all. He renders p.noute at Acts 7:43 as "the god," giving us "And ye took the tabernacle of Molokh and the star of the god [Coptic, p.noute] Rephan, the forms which ye made to worship them."
Likewise, at Coptic John 1:18 we have "the god, the only son," i.e., the god previously mentioned at John 1:1c, who is the Son of God.
This is so because both John 1:1 and John 1:18 describe a contrast between God and his Son. In John 1:1, the Son or Word is "with" or "in the presence" of God. At John 1:18, God is the One Whom no one has ever seen, whereas the Son is the one who represented or revealed Him on earth. Identity of the Son with God is not the theme of either John 1:1 or John 1:18, whereas contrast is emphasized.
Sahidic Coptic John 1:18, therefore, cannot be used to contradict John 1:1, because the translation, "God the only Son" is not the only possible or contextually accurate translation of this Coptic verse in English. John 1:18 is not identifying the divine Son as being the same as God Almighty, but is actually highlighting the distinction between them.