I think it is more useful to use the formulation we offered in that essay. Focusing on what can or can’t be declared allegorical, even though it’s the most frequently found phrasing of the problem, misdirects us from the core points.
The Me’iri (Avos 3:11) tells us that there are three kinds of verses: phrases that are clearly allegorical and not literal; phrases that are literal; and phrases that are both. Mind you he is saying this in explaining the mishnah that tells us that someone “who reveals explanations in the Torah which aren’t as the halakhah” has no portion for the world to come. The determination of which verses are allegorical and which not was given at Sinai, and can only be determined by tradition.
We also see from the Me’iri that declaring something an allegory isn’t the same thing as saying it’s not historical. Hashem is just as capable of authoring a history that stands to the student of that history as a parable from which to learn as He is capable of authoring a story in a text. In fact, “ma’aseh avos siman labanim — the act of the forefathers is a sign for the offspring”, demands that we look at the biographies in Tanakh through this perspective.
Second, the Maharsha condemns a stream of thought amongst Rabbis in Provence, who stated that Avraham and Sarah represent chomer and tzurah (substance and form), the 12 brothers represent the 12 astrological signs and the forces behind them. However, for all we know, his opinion was based on a misunderstanding of their position. Did they mean — as the Maharsha assumes — that there was no historical Avraham and Sarah, that the story is actually Hashem’s way of teaching us about chomer and tzurah? Or, that Avraham and Sarah truly did exist, and their lives were depicted in the Torah as they were so that the lives serve also as lessons for us of deeper truths?
Regardless of which they meant we see here the difficulty in determining whether a rav was calling something ahistorical. The positive claim “this is allegory” is insufficient.
Third, there are a few oft-cited statements as predecessors to the idea of creating our own interpretations that I feel are not applicable.
a) The Rambam writes that the three angels that Avraham saw as men coming to visit him came in a prophetic vision. In fact, he adds, every time an angel appears in a story, the story must be a prophetic vision. (I wrote in Mesukim more about this concept and the Ramban’s rejection of it, and my understanding of the Abarbanel’s take on the debate, and my own theory about the underlying dispute.)
This is often cited as an example of the Rambam using Aristotilian philosophy to deviate from accepted understanding of these episodes. However, it’s neither based on Aristotle, nor the Rambam! The Rambam cites Rav Chiyya haGadol in Bereishis Rabba 48. No deviation.
b) The Ramban attributes the rainbow to nature, whereas Chazal (Avos 5:6) speak of the rainbow as being among the things created twighlight at the end of the week of creation, in a list that includes Bilaam’s donkey, the mon, etc… Furthermore, the Ramban explicitly states that he is doing so because Greek science shows that it’s a natural phenomenon. That the rainbow did not first appear after the flood as a sign of Hashem’s covenant with Noach, but that it was a preexisting phenomenon that Hashem appointed as a sign.
But again, this is also a non-example, as the list ends “the writing [on the luchos] and the art of writing”. A sofeir does not violate the laws of nature every time he puts quill to parchment. Being on the list means that it was significant and part of the Divine Plan from the begining. Not that it’s miraculous.
c) Rav Zvi Yehudah Kook labels all of the Torah before Hashem’s command to Avraham “Lekh lekha” to be prehistoric (assuming פרה- is being used to spell “pre-”, not “parahistoria”). Does this not mean that one can take the same approach to this entire section of the Torah that one takes to the week of creation? If that week need not be a week, why must the flood be a flood?
Again, not really. He’s using a loan word from English. When an archeologist calls something “prehistoric”, he isn’t saying it’s less real, or mythical. He’s saying that is comes from a period before we can establish an organized history. R’ ZY Kook is labeling the pre-Abrahamic material “prehistoric” as an introduction to asking why the Torah begins there, and not with the forefathers.
Much of the dispute is also what people see to be the primary question. In that sense, it’s like the abortion debate. One side calls itself “pro life”, because to them the question is whether one supports the sanctity of life or not. The other, “pro choice”, because they are looking at the issue as a matter of autonomy.
To the rabbis who banned R’ Natan Slifkin’s works, the question of innovation to accommodate science is one of emunas chakhamim, faith in our sages. To those who are bewildered by the ban, it’s one of seeking comprehension. So, while one side asks for an explanation, the other responds that demanding justification and not simply trusting the ruling, is itself a symptom of the problem. They can’t sit down to explain their position, because to do so would be to defeat it.
Another question, as we saw above, is determining how much, if any, of the Torah is necessarily literal history. Must the first moment of time have been 5766 years ago? What about the flood and the tower of Babel? The forefathers? One is obligated to believe in the Exodus and Sinai, so it would seem the line, if any, must be in Genesis. If one makes the line that of halachic obligation, is it at Yaaqov’s encountered with Lavan, since one who brought a bikurim offering had to state “Arami oveid avi — An Aramian/trickster [attempted to] destroy my forefather”?
Or one can see the question as the scope of mesorah. Is it halakhah, and only those beliefs that impact halakhah? After all, can one speak of an obligation beyond the scope of halakhah — isn’t that a paradox? In which case, can we treat everything else merely theory to support the halachic lifestyle? This would ruling is in disagreement with the Tosafos Yom Tov I cited in the earlier essay, who rules that one must even understand the verse “and Timnah was a concubine” in a manner consistent with tradition. It would also be in disagreement with the Rambam, or at least my understanding of his position.