Sukkos. Reb Meir Simcha about When Sukkos Got Its New Name, and My Suggestion about Ancient Origins.

Reb Meir Simcha's interesting addition to the Gaon's vort.  The Gaon, of course, answers the Tur's question about the timing of Sukkos in the Fall when we first experienced being in Sukkos in the Spring.  He says that with the sin of the Eigel the Ananei HaKavod went away.  The sin was forgiven on Yom Kippur, on the eleventh Moshe gave us the tzivui to build the Mishkan, they collected on the twelth and thirteenth, the donations were determined to be sufficient and the people were told to stop bringing on  the fourteenth (or it was Shabbos and it was assur to do anything, see Shabbos 86b,), and they began building on the fifteenth, at which point the ananim came back.  It is the return of the ananim that we celebrate.

Reb Meir Simcha in Parshas Mishpatim points out that the holiday is only called Sukkos in Sefer Devarim.  He says this is because it was only after Moshe's return that it acquired a new meaning and its new name.  The holiday existed before, but it was exclusively agricultural, and it was only called Chag Ha'Asif.  After the kaparah and the return of the Ananim, the date acquired a new meaning and the holiday was given its new name, Sukkos.

Reb Meir Simcha:

חג האסיף. וכן ב'כי תשא' (להלן לד, כב). לא כן בדברים (טז, יג) כתיב 'חג הסוכות'. הטעם על פי דברי הגר"א (שיר השירים ד, טז) כשניתן לוחות השניים ומשה ירד מן ההר וחזרו ענני הכבוד בט"ו לחודש תשרי נצטוו על סוכות כידוע. ולכך, אז קודם דברות שניות נקרא חג האסיף ולא חג הסוכות. ומסולק קושיית ר' חנינא בראש השנה דף יג ע"א יעויין שם והבן, ולא שייך לקרותו חג האסיף על סוכה, ועיין

Reb Meir Simcha's interpretation is reminiscent of the idea that Pesach, or at least celebration that involved eating Matzos, preceded Yetzias Mitzrayim, as we see from the stories of Avraham (as we discussed here) and Lot.  No doubt, it had some meaning even then, but it certainly wasn't called Pesach.  Pasach on what?  It was probably just called Chag HaMatzos.  But once we left Mitzrayim, and Hashem was Posei'ach on our houses, it got a new meaning and a new name- Pesach.

Now that Reb Meir Simcha has told us that the Holiday was celebrated for a different reason until a later date, at which time it acquired a new meaning and a new name, I offer you my speculation about the holiday in even more ancient times, when I had an entirely different meaning.

I suppose this might be of some use for those of us that are asked, by Gentiles or uneducated Jews, to explain why we sit in Sukkos.  One can do as Reb Yaakov does in his Emes L'Yaakov, and offer the alternatives of the agricultural explanation-חג האסיף and  פסולת גורן ויקב, or the religious explanation- ענני הכבוד , סוכות ממש, but I suggest that the simplest thing would be the following.  Sukkos is a holiday that commemorates our national origin as tent-dwelling desert wanderers.  It's kosher, it's simple, and it's not incorrect.  

R' Tal Benschar, in the comments, points out that this pshat disregards the explicit statement in the Torah that Sukkos is because כי בסוכות הושבתי את בני ישראל and nothing else.  

But I still say that if it's also called Chag Ha'Asif, which tells us that it has a meaning besides בסוכות הושבתי את בני ישראל.  If it has additional meanings besides כי בסוכות הושבתי את בני ישראל, I can offer, speculatively, this meaning as well.