A Bodmer Papyrus (not 3 Cor)
3 Corinthians, which is an apocryphal correspondence between the Corinthians and Paul, is a text that many scholars date to the end of the second century (e.g., Benjamin White, Steven Johnston, Richard Pervo, Gerard Luttikhizen). The argument hinges upon an apparent lack of specificity with regards to the heretics mentioned: i.e., its aim is all gnostics.
On the other hand, several other scholars, myself, Rordorf, MacKay, D’Anna, believe that the heresy appears to agree with great specifity with Saturninus (early 2nd century), as described by Irenaeus, haer. 1.24.
While there has really been no extended arguments with regard to the date of 3 Corinthians, it would seem that much of what goes among late daters is either a case begging the question or a violation of Ockham’s razor. So for example, these scholars also date the Pastoral Epistles late, early second century, and therefore, 3 Cor must be even later. This is a tendency I am starting to resist. I think that Acts of Paul is dependent on 3 Cor. But I would still wish to propose a date for 3 Cor independently of considerations about the date of the AP lest I fall into circular reasoning or into building a hypothesis on a hypothesis.
The late date of the 3 Cor also depends on viewing Irenaeus’ information of about individual gnostics with great suspicion. Still, they often admit the specific agreement with Saturninus as proposed by Rordorf–but that doesn’t matter. As Johnston writes (MA Thesis, Laval, 2004),
Il semble donc que l’on doive résister à la tentation d’identifier à tout prix et de manière précise l’hérésie combattue par la Correspondance. Par l’identification d’un groupe particulier ou d’un système particulier à partir des notices d’Irénée, le chercheur d’aujourd’hui risque d’être victime de la classification hérésiologique que construit ce dernier. Irénée s’applique en effect à présenter le gnosticisme comme un phénomène systématique, dont les nombreuxes ramifications peuvent se ramener à un ancêtre commun qui est Simon le Magicien, qu’il considère comme le “père de toutes les hérésie”.
[It seems therefore that one must resist the temptation to identify at all cost and in precise manner the heresy combatted by the Correspondence. By identifying a particular group or particular system based on the information of Irenaeus, the contemporary scholar risks becoming a victim of the classification of heresies which Irenaeus has constructed. Irenaeus makes an effort to present gnosticism as a systematic phenomenon, whose numerous ramifications can be assigned to a common ancestor, i.e., Simon the Magicien whom he consider to be the “Father of all heresy”.]
On the other hand, 3 Cor could be an early example of a text which tries to demonstrate the later heresies go back to arch-enemies of the first century; Justin lists Simon and Menander together (1 apol 56); Hegisippus lists gnostics of the second century as deriving from Simon, Cleobius, Dositheus, and Gorthaeus (in Eusebius, h.e. 4.22.5). There is no reason to think that Irenaeus was the first to do this. The important thing is not so much whether Irenaeus accurately depicts the views of individual gnostics, but whether he accurately depicts the orthodox view of what these gnostics each taught. In that case, we have a very good match of 3 Cor’s opponents and haer. 1.24.
Late daters tend to neglect certain other criteria for dating 3 Cor. 3 Cor exhibits no specific signs of polemicizing against Marcion, no advanced form of gnosticism (like Valentinus or Basilides), and a very primitive church structure (the lead presbyter is a primes inter pares). Its orthodoxy is very similar to Ignatius of Antioch. There is thus no reasons to suggest that it doesn’t belong to the first quarter of the 2nd century, and other reasons why it doesn’t belong to the late 2nd century.