[Avodah] Theoretical and Real Shiurim

[Zev Sero]

On 5/04/2012 5:44 PM, Micha Berger wrote:
> Or, comparing to acharonic shitos, we get somewhere between the CI's
> *lemaaseh*  of 17cc

Where is that from, exactly?  For what application.  Don't forget
that the classic definition of a kezayis is *either* 1/2 or 1/3 of
a kebeitza, so for derabanan purposes such as maror, or where
smaller is a chumra, RACN says 18 cm^3.  Adjust now that we know the
Rambam's dirham was about 12% smaller than the Ottoman one, and we're
not far off.


On 5/04/2012 5:44 PM, Micha Berger wrote:
> Yes. I was*trying*  to say they had a mesorah of a broken value for
> which year is shemittah. After all, that is a 5th example of process
> defining law despite our (or in this case, the Rambam's) determination
> of the facts.

But they had an actual mesorah.  It's not just a matter of them being
the geonim so he must defer to them.  It's "im kabalah hi nekabel".
He's deferring to them not because of their authority but because he
believes that they have this ish mipi ish from Chazal, so his
understanding of the gemara must be mistaken.  So it's like if we had
a hin measure from the BHMK that had been handed down in some family
of kohanim on Djerba or somewhere, that was marked "hin" and we could
measure it and derive our shiurim.  That would surely override all
our cheshbonos, wouldn't it.  That's what the Rambam is deferring to.


On 5/04/2012 5:04 PM, Zev Sero wrote:
> On the contrary, he says they have an *unbroken*  mesorah that what Chazal
> did during Galus Bavel and again after churban bayis sheni was different
> from what he thinks they ought to have done.  And he therefore defers to
> that mesorah, and the count that results from it, because he accepts that
> it is unbroken since Chazal's time.

To make this clearer, I'm saying that this is in the same category
as R Yehoshua holding that Rabban Gamliel was wrong to have been
mekadesh the chodesh when he did.  Even leshitaso, however, Yom Kippur
was when RG said it was, not when RG ought to have said it was.
I think the Rambam is doing a similar thing in Hil' Shmitta Veyovel:
he's saying that according to his understanding of what Chazal *said*,
they ought to have counted one way; but we have a mesorah that they in
fact counted a different way, and shmita follows what they did, not what
(we think) they ought to have done.  (Leaving aside the fact that it's
the same Chazal.)

-- 
Zev Sero
zev at sero.name