Aliyat HaDorot

Beginning with background information from this continuing online discussion:

(Pirkei Avot, on the transmission of Torah since Sinai, contributed by 'int')

Moshe received the Torah from Sinai and passed it on to Yehoshua; Yehoshua to the Elders; the Elders to the Prophets, and the Prophets passed it on to the Men of the Great Assembly.

(Soncino Talmud Chagigah 16a, footnote 42, contributed by 'melech')

In the J. Hag. II, 2 we are told: At first there was no controversy in Israel except over the laying on of the hands alone. But Shammai and Hillel arose and made them four (in Bab. Shab. 14b, only three points of dispute are mentioned; cf. Tosaf. to our passage). When the disciples of the School of Hillel increased, and they did not study sufficiently under their masters (lit., ‘did not sufficiently minister to their masters’), the controversies in Israel increased, and they became divided into two companies, the one declaring unclean, the other declaring clean. And (the Torah) will not again return to its (uncontroversial) place until the son of David (i.e., the Messiah) will come.

(contributed by 'melech')

Pre-Chazal times were seen as perfect (yeridat ha-dorot and all that) and the controversies only arose much later.

(Gate Of Reincarnations, Chapter 37, The Ari, contributed by 'liorah')

Further down to the east there is an opening to a cave with a garden above it, and to the west side of the cave below there are three cracks. That is where Yossi ben Yoezer, Yossi ben Meshulam, and Yossi ben Yochanan are buried-opposite the three cracks.

(Yerushalmi Chagiga 2:2, contribued by 'TipuseiHarim')

From Moshe to the Yossis, who are the first of the pairs who receive the mesorah as listed in Pirkei Avot, no conflict of halacha arises which cannot be settled.

Yossi ben Yoezer and Yossi ben Yochanan disagree over whether semicha (pressing hands to the head of an animal about to be sacrificed) should be performed on yom tov. This dispute passed through all the zugot, down to Hillel and Shammai (note: 4 or 5 generations later), who added three additional bones of contention (note added: at which time disputes and forgetfulness of Torah increased).

(Temurah 16a, contributed by 'TipuseiHarim')

Chazal says that torah was forgotten by the end of the days of Yossi ben Yoezer.

4 Key Areas Of Disagreement Leading To Torah Being Forgotten

Taken together, the data suggest that there were 4 key areas of disagreement which led to Torah being "forgotten"; the first being the disagreement between Yossi ben Yoezer and Yossi ben Yochanan over semicha and the later 3 during the times of Hillel and Shammai.

Link To The End Of Days

"The language is that by the end of R. Yossi ben Yoezer's days, torah was forgotten" hints to the idea of "the end of days".

First & Subsequent Splits Leading To Forgetfulness

The two Yossis and Hillel and Shammai are 4 men. The "end of days" can refer to the dark feminine principle.¹ So, it seems to me a possibility that the third Yossi (ben Meshulam) not mentioned with the 2 Yossis (ben Yoezer and ben Yochanan) who initiated the whole forgetting thing is connected to a split - Yossi ben Meshulam (masculine force) and "the end of days" (feminine force) of one "whole" Yossi, leading to forgetfulness in the feminine force which was expressed as forgetfulness in the masculine force in the time of Hillel and Shammai - see what I'm saying?

There is 1 key area which led to forgetfulness in the feminine, and 1 + 3 = 4 key areas which led to forgetfulness in the masculine.

Master Key To Remembrance, Semichah & Transmission

Consequently, it seems to me that Yossi ben Meshulam is the single master key to remembrance by the feminine, who can in turn "undo" the other 3 areas leading to forgetfulness in the masculine.

Aliyat Ha-Dorot

This is further supported by the fact that pre-Chazal generations were seen as yeridat ha-dorot given that the expressions dor dor, dor v'dor and/or dor l'dor represent an unwanted separation and discontinuity between Netzach and Hod.¹ Consequently, the phrase yeridat ha-dorot implies the opposite of separation between these two sefirot. In other words, the phrase yeridat ha-dorot implies a 4-fold unity of the "two sons of Yosef" (Yesod) with Netzach and Hod prior to the dispute between Yossi ben Yoezer and Yossi ben Yochanan. A 4-fold reunification of these sefirot could be called aliyat ha-dorot.

It makes sense too, given that Hod and Netzach are related to learning and transmission, respectively.

footnote:

¹ Sha'are Orah, R. Yosef Gikatilla