[Avodah] measurement error

Micha Berger via Avodah avodah at lists.aishdas.org
Wed May 27 18:33:24 PDT 2015


The topic I got caught up in has been the AhS and standard shiurim.

The story so far....

Jan 8, when this thread was current,  I wrote
<http://www.aishdas.org/avodah/vol33/v33n004.shtml#13>:
> BTW, carrying 4 amos bereshus harabbim is 4 of one's own amos, assuming
> they have mainstream bone structure. It's where I am in AhS Yomi.
> But notice that we would naturally assume "amah" as unit of length, not
> as a function of how far that particular person can reach.

On Jan 11, I hit the topic again WRT eiruvin AhS OC 363:32-35, and wrote
<http://www.aishdas.org/avodah/vol33/v33n006.shtml#01>:
> But then in se'if 34 he says something I do not follow, but key to
> our discussion.

> When dealing with mavui, where there is only one mavui and therefore one
> measuring process to be used for everyone, the above applies. However,
> when the measurement is only for one person's use, tbey should be
> measuring for himself, with his own norms.

> And here he adds a touch of subjectivity: a person should measure how
> far he himself could walk. And the rule of carrying in rh"r a distance
> of no more 4 of one's own amos is brought into that umbrella.

> The reason for the general rule is to cover the personal amos of the
> people who will be using the measuring.

> BUT, and this is why I do not follow, he opened se'if 32 by telling us
> the variability is 1/48 of the total (1/24 of an etzba per ammah). Which
> is far less than the variability in forearm lengths in most groups of
> people. For example, my own sukkah is used by Yoni, who stands 6'3" and by
> my own 5'3" -- and my arms are on the shorter side, even proportionally.
> When we hold up elbows together, my ammah ends just past his wrist. Not
> within 47/48 of eachother.

And then on May 18 I hit AhS OC 586:14 and tried reviving this thread
<http://www.aishdas.org/avodah/vol33/v33n080.shtml#04>. The topic
was the minimum length for a shofar -- long enough to be seen on
either side when being held in one hand.

> So the shiur is neither personal nor really the standard tefach. It is
> literally as the gemara says, what can be held and still seen. Which is
> why there is a machloqes about where the tefach stands in relation to the
> real shiur. But, visible if hypothetically held by an average hand. And
> if the tqoei'ah has wide hands, he could hold a minimal shofar without
> it being visible, and it would still be kosher.
...
> What I find even more interesting is that there is no chiluq being drawn
> between someone who blows in shul and someone who blows just for himself.
> Wouldn't the rule from OC 363 mean that someone in the latter situation
> should use what is visible when their own hand holds it?

But today I seem to have hit an AhS which deals with shiurim that aren't
human: revi'is, kezayis. According to OC 612:8, the shiur of drinking
on YK is not a revi'is, but melo lugmav. And unlike akhilah, where there
is one kezayis for everyone, melo lugmav is literally his own cheek. So
it would seem that kezayis, and perhaps revi'is and other shiurim (beis
se'ah) are not subjective. Which makes sense, since I can't figure out
how to make a kezayis correspond to the person...

Except RCVolozhiner's position, where it's the average kezayis then and
there, and not a static shiur. Which could, literally, be the same shiur
for all people (living there and then) and thus may be within the AhS's
intent.

Can't I get anyone else intrigued by this problem?





Back on Jan 11, I was in hil' eiruvin, and hit upn the AhS's discussion
of an ammah just as we were discussing the topic 

Tir'u baTov!
-Micha

-- 
Micha Berger             The purely righteous do not complain about evil,
micha at aishdas.org        but add justice, don't complain about heresy,
http://www.aishdas.org   but add faith, don't complain about ignorance,
Fax: (270) 514-1507      but add wisdom.     - R AY Kook, Arpelei Tohar



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