Our Gemara on Amud Aleph discusses the power of established custom as a vehicle of verified tradition, to the extent that it can override other rabbinic declarations. The Gemara emphasizes this with the striking phrase: “Even if Eliyahu HaNavi would come and state that chalitzah may not be performed with a particular kind of shoe, and the custom is to use that kind of shoe, we do not listen to him, since the custom is already established.”

The previous Satmar Rebbe (Igros Maharit IV, p. 132) reflects on this phrasing. Why say “if Eliyahu HaNavi would say,” when by definition Eliyahu would never make a false statement? The Gemara could have stated more precisely that even Eliyahu has no authority to override an established custom. The Rebbe explains that the Gemara emphasizes a subjective point: even if a figure who appears to us as a prophet or supreme authority were to make such a claim, it still would not override minhag.

The limits of rabbinic authority and the power of the collective wisdom of Klal Yisrael are a fascinating area of halacha. There is a belief that the collective possesses an innate tradition with independent authority. Later in Menachos (35a), Rav Ashi advises observing what people actually do in practice as a source for halacha.

Rav Kook in Oros HaKodesh (3:3:5) speaks of the innate Ruach HaKodesh within the collective soul of the Jewish people. In Shemoneh Kevatzim (2:30), he applies this idea to explain historical situations in which seemingly erroneous practices became accepted. He writes:

At times, when there is a need to disregard words of Torah but there is no one in the generation who can show the way, the matter comes about by means of a disruption. At any rate, it is better for the world that such a matter comes about by means of an error. In this inheres the principle, “Better that people [do wrong] in error and not with purposeful intent” (Beitzah 30b). Only when prophecy is present in [the nation of] Israel is it possible to institute such a matter – by means of a temporary injunction. Then it is done openly, with permission and as a Godly command. But in consequence of the sealing of the light of prophecy, this rectification come about by means of a [longlasting] disruption that, although it dismays the heart from the aspect of its outer being, causes it to rejoice from the aspect of its inner being.

Rav Kook holds that in modern times, without a Sanhedrin, the collective unconscious wisdom of the Jewish people can channel God’s will. This explains how certain customs and sensitivities evolve organically within halacha, even without formal rabbinic enactment.