[Avodah] Leap Years before matan Torah?

[Micha Berger]

On Thu, Oct 21, 2021 at 05:33:29PM -0400, Zev Sero via Avodah wrote:
> A more sophisticated answer might be that since we have a rule that when
> there is no sanhedrin we use a formula, that rule applied not only when the
> Sanhedrin ceased to function during Galus Bavel and again in the 4th century
> CE, but also before there was a Sanhedrin in the first place.

Rabbeinu Bechayei (Chumash, not CV) quotes and agrees with
Rabbeinu Chananel that even when there is a Sanhedrin, they used a
formula. Leshitasam, the role of eidim was formal / procedural, and not
the cause of the new month.

That said, since even as late as Abayei there is discussion about things
that are impossible in our calendar, like not knowing the length of Elul
and therefore the date of RH, or the Mishnah's discussion of the various
different dates the Megillah could be read on, etc... I don't see how
these rishonim could mean that the computations were the same we use
today. Just that every Sanhedrin had a computation they would use, and
accept witnesses to fit.

The problem with this for our OP is a problem we have in general with
the idea that the avos keeping kol haTorah qulah. If the halakhah changes
through the centuries as a later Sanhedrin contermands earlier pesaqim,
who would Yitzchaq Avinu have held like?

Tir'u baTov!
-Micha

-- 
Micha Berger                 "The worst thing that can happen to a
http://www.aishdas.org/asp   person is to remain asleep and untamed."
Author: Widen Your Tent             - Rabbi Simcha Zissel Ziv, Alter of Kelm
- https://amzn.to/2JRxnDF