[Avodah] Theoretical and Real Shiurim

Micha Berger micha at aishdas.org
Thu Apr 5 12:46:55 PDT 2012


First, the disclaimer... Recall that I don't think determining the
historical size of the kezayis can create qulos.

We can approximate the volume of Chazal's kezayis from the length of an
ammah as implied by Chizkiyahu's Tunnel and Har haBayis. As I wrote 2
years ago <http://www.aishdas.org/avodah/vol27/v27n116.shtml#05>, the
tunnel yields 43.75 - 44.4 cm, and markings on Har haBayis at regular
intervals implies an ammah of 43.25cm.

A kezayis is a third of a revi'is, which is 2x2x2.7 etzba'os (10.8 cubic
etzba'os), and each etzba is 1/24 ammah.

Let's take a ballpark number of the amah of an even 44cm, yielding an
etzba of 1.83 cm, or a revi'is of 20 ml. (Given the approximation from
the data, I'm rounding.) A kezayis would be 6.6 cc.

Given the remains of olives found in Masada, and from trees that old
which still bear fruit today, we know that the middle sized breeds of
olive eaten in those days were the suri 2.5-3.5 cc, and the nabali 4-6 cc.

So, both the archeological evidence of the amah and the more
straightforward way of looking at olives, are in the same kind of
ball park, which is a shade larger than R' Chaim Volozhiner's 3 cc,
but much smaller than the next (in size) on RDBannett's list, the
CI's lemaaseh (as per R' Chaim Kanievsky) of 17 cc. RACNaeh at 27cc
is WAY WAY larger.


But to return to my theme:

I really think that the argument has to be halachic, or else we need
to be machmir anyway so as not to violate minhag Yisrael on the range
of accepted pesaqim. No? Accepted halakhah (nispasheit lekhol Yisrael)
creates legal authority. If we could prove that following the pesaq
creates halakhic problems, eg requiring a ciliac to stretch the limits
of his tolerance, or relying on a mistakenly large kezayis for akhilah
on YK, we would have a different discussion.

This question of error in history is much like our discussion of the
alleged abiogenesis of maggots in meat, an error in science. We have
those who explain the din in new terms, who decide the science isn't
what they were really talking about, or the Gra's and RAYKook's shitah
that eliminating one reason to be machmir doesn't prove we eliminated
all the reasons to do so. All lines of reasoning that allows changes
in our understanding of the metzi'us to change halakhah only allow it
lechumerah. Even the saving on Shabbos of a premature baby born in the
8th month follows the general rule to be machmir on piquach nefesh rather
than other dinim.

Tir'u baTov!
-Micha

-- 
Micha Berger             Every second is a totally new world,
micha at aishdas.org        and no moment is like any other.
http://www.aishdas.org           - Rabbi Chaim Vital
Fax: (270) 514-1507




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