While a proponent of an early date for the Gospel of John (he places it to 68-70), Jonathan Bernier wrote the following about the attestation of the Gospel of John in texts such as P52, and, unlike some pop-level Protestantapologists, opts for a later date of such texts:
External
Attestation
When it comes to external
attestation, for the better part of a century it was supposed that P52,
a fragment of John’s gospel originally dated to the early to mid-second
century, established that the Gospel cannot date much later than 125. More
recent estimates have suggested that P52 could date to the late
second century or even into the third. Similar tales could be told about other
early witnesses to the text of John’s Gospel, such as P60 and P75.
Although dates as early as the second century have been proposed for both, more
recent work has tended toward the third or even fourth century. Given the
vagaries of the data, P52, P66, and P75 cannot
be used to establish that John’s Gospel existed in the first half of the second
century. Indeed, on the strength of the manuscript data alone, one could not,
for instance, rule out J. V. M Sturdy’s argument that John’s Gospel was
completed ca. 160. (Jonathan Bernier, Rethinking the Dates of the New
Testament: The Evidence for Early Composition [Grand Rapids, Mich.: Baker
Academic, 2022], 88)
Further Reading:
Modern (Evangelical Protestant) New Testament Scholarship vs. Christina Darlington
