It seems obvious to most scholars that our estimate of the age of a certain book . . . must be founded on information contained in the book itself and not on other information, and the estimate should certainly not be based on the existence of a historical background that may never have existed.
The above passage is from a chapter in Did Moses Speak Attic? by Professor Niels Peter Lemche of the University of Cophenhagen. The . . . omitted words were “of the Old Testament” but I omitted them in order to suggest that the same logic applies equally to books of the New Testament, in particular the Gospels.
The passage continues:
Although seemingly self-evident, this method is not without fault, and it may easily become an invitation to ‘tail-chasing’, to quote Philip R. Davies. By this we intend to say that the scholar may soon become entangled in a web of logically circular argumentation which is conveniently called the ‘hermeneutical circle’ . . . .
I have outlined Davies’ straightforward arguments for circularity at http://vridar.info/bibarch/arch/davies2.htm
There is another key and closely related point that is, I believe, at the heart of the dating of the Gospels.
Another points is that it is also supposed that the reading of a certain piece of literature will automatically persuade it to disclose its secrets — as if no other qualifications are needed.
That is exactly how the Gospels are dated from all I have been able to determine of various works about Gospel dating I have read. Most of them focus on the “Little Apocalypse” of Mark 13 (adapted in Matthew 24 and Luke 21) and work from the assumption that by matching statements there (wars, abomination of desolation, etc) with possible events in the 40′s or 60′s and 70 they can determine that the Gospels were composed around those same years. To suggest that they may be dated quite some time after those events is often considered to be an arbitrary and tendentious position. I believe that the reverse may in fact be the case, as I argue in what follows.
Lemche continues, and I insert terms that I believe make his logic equally valid for the Gospels:
The first point to discuss will be the circular argumentation that is based on a too close ‘reading’ of the biblical text. . . . Some assume that these books must be old simply because they say that they are old. The exegete who claims that the books . . . must perforce be old will . . . have to accept the claim of the books themselves by either rather naively assuming that [an eye witnesses] could be the author . . . or by more sophisticated argumentation, for example, of the kind formerly often used to prove narratives . . . to be old because only an eye-witness [or oral tradition closely related to eye-witnesses] would have been acquainted with the particulars [narrated]. (p. 293)
How to escape this circularity?
In order to escape from the trap created by this circular method of argumentation and the rather naive understanding of the biblical text that lies at the bottom of such claims, it will be necessary to go further and find arguments not necessarily part of the biblical text itself but coming from other sources. Such information alone will be able to disclose to the reader that the [Gospels] were composed, not at [the 40s or 60s or 70s] but at a much later date.
Scientific procedure or its reverse?
Although it has become a standing procedure in the study of the Old Testament [Gospels] to begin where we know the least and to end at the point where we have safe information in order to explain what is certain by reasons uncertain and from an unknown past, it is obvious to almost everybody else that this procedure has no claim to be called scientific. We should rather and as a matter of course start where we are best informed. Only from this vantage should we try to penetrate into the unknown past. (p. 294, my emphasis)
The first time we have secure and verifiable confidence of the existence of the Gospels is in the latter half of the second century with the writings of Irenaeus.
Working back from that position we come to Justin in the mid second century and find some indirect hints that he may have known of the Gospels in a form not far removed from how we know them. Justin certainly speaks of quite a few things we find in the Synoptic Gospels. We sometimes find a phrase here and there in other works that we find likewise appear in the Gospels.
But we have no external basis at all to support our model that the narratives found in the Gospels are themselves historical or that they were composed within ear-shot of eyewitnesses of the events they narrate. The only rationale for this assumption is that the Gospels tell the story and sound like they are relating real events so we believe there narratives are derived from real history.
Some have attempted to justify this position by claiming that the only way we know of anything in the past is by the ancient works that speak of these events. But that position is really a common street understanding of how we gain our knowledge of the past. It is not scholarly. Any historian worth their salt evaluates the sources they use by firstly ascertaining their provenance, nature and reliability. Historians who have naively relied upon single sources without subjecting them to such tests have ended up with egg on their faces when others have come along and performed the tests that should have been done in the first place. See, for example, Liverani’s observations of early Hittite historians. But at least those Hittite historians did have a certain provenance for their source — a royal monumental stone — while for the Gospels we don’t even have anything comparable.
In the case of the Gospels we have only the self-testimony of their narratives and none of the additional resources we need to yield to us the answers we need in order to make judgements about the historical foundations of their narratives and when they were written. Even their genre is open to debate and it is genre that is an important (though not necessarily decisive) key to understanding the sorts of information their authors thought they were expressing.
The internal evidence of the Gospels gives us a start by date (terminus a quo). The external evidence gives us the finish by date (terminus ad quem).
The internal evidence is more than the Little Apocalypse, however. Synagogues and Pharisees as features of the Galilean life, and the sorts of characterisations of Pharisees we read about and the conflicts between Christianity and the rabbis we encounter in the Gospels, the beginnings of persecutions, not to mention the existence of Nazareth itself, are according to archaeological and other literary evidence very late first century or early second century developments.