Textual Criticism is a necessary, if sometimes maligned, activity. The substance of textual criticism is the comparison of manuscripts to determine which reading is most likely to be the original. John 1:18 is a case in point.
No one has ever seen God; the only God [monogenes theos], who is at the Father’s side, he has made him known. [ESV]
No one has seen God at any time. The only begotten Son [monogenes huios], who is in the bosom of the Father, He has declared Him. [NKJV]
While the former reading is support by important early manuscripts like the Codex Siniaticus and the Codex Vaticanus, the latter has the support not only of the Byzantine family of manuscripts but also early witnesses like Irenaeus, Clement, Hippolytus, and Eusebius. Though many translators give preference to the witness of the Codex Siniaticus, in this case the array of witnesses supporting the latter reading is also compelling. Where the textual witness does not indicate the preferred reading with certainty, there are a number of principles brought into play by the textual critic; the primary principle is: “choose the more difficult reading”.
With regard to John 1:18, the more difficult reading would certainly be monogenes theos (‘only-begotten God’ or ‘the only God’)—nowhere else in the New Testament do we find the suggestion of there being more than one God. If we were to follow the principle outlined above we would say that monogenes theos is more likely to be the original reading. However, this reading is almost too difficult. If monogenes carries the meaning of literal begettal then we have a contradiction since, by definition, God cannot have a beginning. If, on the other hand, monogenes carries the meaning of ‘unique’ or ‘first-ranked’, as many scholars believe, then we are in greater difficulties because this would make John say that Jesus is the ‘one and only God’ [cf. NIV!] despite calling the Father ‘God’ in the very same verse. Even by modern Trinitarian standards, this is heretical. Since John regularly uses the phrase monogenes huios (‘only-begotten Son’—John 3:16, 18; 1 John 4:9), it is reasonable to suppose that this is the original reading.
In sum, though a difficult reading is often likely to be the original, we should bear in mind that there is more than one reason why a text might contain a less difficult reading. The advent of Trinitarian thinking was responsible for more than a few theological ‘corrections’.[1]
[1] For a study of theological changes to the text see B. D. Ehrman, The Orthodox Corruption of Scripture (Oxford: Oxford University Press, 1993), and for his discussion of John 1:18, pp. 78-82.
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