[Avodah] halachic reality and scientific reality

[Micha Berger]

On Wed, Jun 03, 2026 at 05:57:46AM +0300, Joel Rich via Avodah wrote:
> In a recent shiur, Rav Asher Weiss summarized his understanding concerning
> differences between halachic reality and scientific reality. They are two
> different realities where the former is set at sof hora (closing of the
> gemara) and becomes a matter of mesora. The latter continues to evolve..

I think this is phrased poorly.

We aren't talking about scientific reality changing as much as our
knowledge of it does.

But when it comes to mesorah, it might actually be the reality that
coalesces. The conceptural reality is eilu va'eilu. What happened at
sof hora'ah was a kind of closing of choosing which we follow lemaaseh.
And that's because eilu va'eilu is the reality, but halakhah lemasseh
is legislative, not which is real.

There is an Oral Torah largely to enable that flexibility, which you
cannot have when working off written codes.

The other problem I have with RAW's position as presented is that sof
hora'ah was only a comparative statement. It didn't entirely end at
the end of the Sanhedrin or the acceptance of the Talmud Bavli. And
not only because rishonim argue about the rules of which statement is
the Bavli's conclusion so they will disagree lemaaseh. Or the gemara
doesn't state a conclusion altogether. And different rishonim could have
different girsa'os.

But machloqesin about what the hora'ah actually was aside, there is
still an evolution of the mesorah after Ravina veRav Ashi. And not
just the accumulation of new dinim, like the normalization of everyone
saying Pesuaqei deZimra daily during the geonic period.

And there are always new applications of existing halakhah. Whether
because people are doing something new, or because they are doing the old
in a way that is only slightly, but halachically relevant, different way.

A case of that latter clause: Once we figured out ways for deaf mutes
to communicate, and thereby they became teachable, they aren't the same
kind of people that the gemara assumes a cheireish would be. It looks
like a change in halakhah, but really it's a change in the realia; a new
case that requires getting into the weeds to see that it is indeed new.

But there were also changes to which eilu va'eilu became universally
accepted pesaq. Minority opinions that came to the fore, even if
not universally accepted, at least from largely ignored to commonplace.

The ge'onim had one definition of sheqi'ah, Rabbeinu Tam was just one
of the majority of Rishonim who had a different one. And then, in the
18th cent CE, most of us switched back.

Look how many fewer Americans keep two full days when in Israel for Yom
Tov than just 3 or 4 decades ago.

There was a sof hora'ah, but it seems thats only in comparison, and
not that there is no hora'ah anymore. After all, R Asher Weiss himself
has a paper somewhere that says "Yoreh Yoreh" -- literally saying that
he is qualified to give hora'ah.

So, halakhah evolves too. But it's legislative, not reality.

Last, even our knowledge of reality changes with each chiddush. Presumably
that's cumulative, and not like the scientific method and experiments
that show we have to refine our theories.

Tir'u baTov!
-Micha

-- 
Micha Berger                 None of us will leave this place alive.
http://www.aishdas.org/asp   All that is left to us is
Author: Widen Your Tent      to be as human as possible while we are here.
- https://amzn.to/2JRxnDF          - Anonymous MD, while a Nazi prisoner