Atlantis said: "Why was Mantey so disturbed? His conclusion (found both in his Grammar and his letter) is that John 1:1 should be translated either "the word was deity" or "the word was God," not "the word was a god." Mantey estimates the evidence "to be 99% against" the Society's translation."
Mantey said: "without the article [in Jn 1:1c] theós signifies divine essence [...] pros ton theón emphasizes Christ's participation in the essence of the divine nature." (139, 140)
(Pp 148, 149) "In Xenophon's Anabasis, 1:4:6, emporion d’ en to xhoríon, and the place was a market, we have a parallel case to what we have in John 1:1, kai theós en ho lógos, and the word was deity. The article points out the subject in these examples. Neither was the place the only market, nor was the word all of God, as it would mean if the article were also used with theós. As it stands, the other persons of the Trinity may be implied in theós."
Mantey appears to be saying that using the "parallel" case of Xenophon's Anabasis, John 1:1c should be translated, not "the word was God," but rather, as "deity," for the word was not all of God."
In his letter, he quotes Harner to bolster his reasoning that when the predicate noun precedes the verb (as in Jn 1:1) the emphasis in on the quality or nature of the subject in discussion. Not that it should be used to identify Christ with God. He made that clear by stating that the market of Xenophon's was not the only market, but "a" market, one of many markets. Applying this to John 1:1c, the NWT translators saw that Mantey unintentionally was allowing a translation: "the word was a god."
The truth is that although Mantey does not like the idea of indefiniteness for John 1:1c, he supports it in Xenophon's case. The issue here is not grammar, but theology. Mantey is wrong to suggest that anarthrous predicate nouns preceding the verb are not indefinite. Acts 28:4 proves him wrong. There, Paul is being called "a murderer" by the islanders. The Greek grammatical construction is similar to Jn 1:1c. Normally, when translators deal with this type of Greek construction they translate it either as indefinite or qualitative. No hard rule. Just the norm.
In conclusion, this seems to be a case where the WT and Mantey are right in some things, and wrong in some others. This is not a case where Mantey is 99% right and the WT is only 1% right. The long list of translators siding with Mantey only proves that most Catholic and Protestant translators believe that Christ is the God. Interestingly, one of the translators he cites, Robert Young, translated John 1:1 as, "the Word was God," but in his later commentary he explained it as, "the Word was a God." He was silent about that. Why?