Volume 56 Number 47
Produced: Thu Sep 25 22:08:13 EDT 2008
Subjects Discussed In This Issue:
Eating fish and meat
[Shimon Lebowitz]
Irrationality of Pi and SquareRoot of 2
[Russell J Hendel]
LeDavid Hashem Ori Veyishi (2)
[Avraham Etzion, Michael Kahn]
Palestinian Talmud
[Jay F Shachter]
Plain Plane Geometry (was Value of Pi and Haredi Haskafa)
[David Maslow]
Protest against new Israeli policy on Sudanese refugees
[Michael Gerver]
Value of pi
[Ben Katz]
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From: Shimon Lebowitz <shimonl@...>
Date: Wed, 24 Sep 2008 08:01:40 +0300 (IDT)
Subject: RE: Eating fish and meat
Eitan Fiorino <afiorino@...> wrote:
> Some believe that what the Torah describes as tzarat may in fact be
> psoriasis (though I can say I never saw a patient who complained their
> psoriasis flared when they gossiped, nor did I ever meet a patient who
> complained his house or clothes also had psoriasis, so for me it is
> not so clear that tzarat is psoriasis).
What actually does seem clear is that the tzara'at of the *Torah* and
the tzara'at of Chaza"l are not necessarily always referring to the same
phenomenon.
Chaza"l do teach us that the tzara'at of the Torah, when inflicted on a
person, is related to lashon hara, and when on a house can be related to
stinginess. Its treatment involves ritual and spiritual matters (such as
the fact that only a cohen is valid to make decisions, regardless of his
knowledgeability).
On the other hand, Chaza"l also refer to an apparently different
tzara'at, which can be caused by eating fish and meat, or by teaching
about it using one's own body as the example (Gitin 57b). Ketuvot 61b
describes a form of tzara'at which can afflict an animal, rendering its
meat unfit for human consumption. I do not remember where, but this
'other' tzara'at seems to be described as being contagious, while there
seems no reason to assume that the purely spiritual one of the Torah
would be.
Ketiva veChatima Tova,
Shimon
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From: Russell J Hendel <rjhendel@...>
Date: Sun, 21 Sep 2008 11:20:46 -0400
Subject: RE: Irrationality of Pi and SquareRoot of 2
This posting clarifies some facts about the irrationality of the
squareroot of two and pi made by Martin and Arnie. But should be of
interest to everyone.
First: What happened 200 years ago what that the FIRST RIGOROUS proof of
the irrationality of pi was provided. However many mathematical facts
are "known" and even "used" centuries before they are proved (Most non
mathematicians are surprised at this but it is true... for example
there are prestegious mathematical papers based on the assumption that
the Riemann hypothesis is true (whatever the Reimann hypothesis is...the
point being that publication does not require complete truth....the
papers are published CONDITIONAL to the hypothesis' truth even though
the hypothesis may one day be proven false).
That being said: All the ancients knew that pi was not known
exactly. The methods for approximating pi to any desired degree of
accuracy were known to Archimedes. For purposes of discussing the Talmud
it is sufficient to realize that they knew that pi was not known exactly
and something had to be done about the approximation. The fact that it
was not rigorously proved till a few hundred years ago is really
irrelevant.
As to the square root of 2: The algebraic 2-line proof presented in a
posting is NOT the proof of choice. Again most non mathematicians find
it hard to understand that prior to the 15th century geometry and
algebra did not mix. So the irrationality was proven geometrically. We
did not even have the notational tools to prove it algebraically (even
negative numbers are a relatively late innovation - people use to have
two checkbooks - alot of what we do today was taken for granted).
In summary: The Talmudic Rabbis were aware of the ambiguity of
measurement whether it be a) 4 cubits b) diagonal of a square, c) area
of a circle. They therefore arranged legal approaches to deal with this
ambiguity. The fact that some ambiguities were "proven" to be
INTRINSICALLY ambiguous at different points of time is not relevant to
this discussion. I again reiterate my position that the various
approximations are default approximations used when a contract does not
explicitly specify one. So if I sell a circular plot of land with a 200
ft radius it is assumed that I have sold 300 square feet (even though I
have sold more) and the seller ONLY HAS TO PAY ME that value. So for
example if my land costs $50 a square foot I am owed $15000. If I had
wanted more I should have put it in the contract. [I know I made this
point previously but no one commented on it and there is a point--the
point here is that if Chazal were telling me a FACT, PI=3, then I could
NOT make a contractual stipulation that pi = 3 1/7. However if ALL
chazal were telling me is that the default value of Pi is 3 then I have
a right to make a contractual clause stipulating an alternate
computation]
In passing in 1897 the Indiana legislature (BIll number 246) tried to
pass a law that pi =3.2 (Correct to the nearest fifth). The law did not
pass but illustrates how legislatures dealt with the ambiguity of pi.
Hope this clarifies this.
Russell Jay Hendel; Ph.d. (in Math); http://www.Rashiyomi.com/
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From: Avraham Etzion <atzion@...>
Date: Wed, 24 Sep 2008 09:35:17 +0300
Subject: Re: LeDavid Hashem Ori Veyishi
There was a lengthy article in last week's edition of HATZOFEH written
by the Dean of Orot College on the history / structure / meaning of that
Mizmor. The bottom line which he documents is that the custom prerdates
the ChemdaT and he notes that it should be said. Consequently there are
no Sabtai Tzi allusions
Avraham Etzion
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From: Michael Kahn <mi_kahn@...>
Date: Wed, 24 Sep 2008 00:07:06 -0400
Subject: LeDavid Hashem Ori Veyishi
> From: Martin Stern
> I am told that the earliest mention of the custom of saying LeDavid
> Hashem Ori Veyishi from Rosh Chodesh Ellul until Hoshana Rabba is in the
> Sefer Chemdat Yamim, first printed in Izmir in 1731-2. Does anyone know
> of an earlier source?
>
> The anonymous author of Chemdat Yamim was accused of Sabbatean
> tendencies by, among others, R. Yaakov Emden and the balance of
> scholarly opinion today is that this is true. I have heard that the
> Sabbateans interpreted some psukim from this mizmor as alluding to their
> heretical doctrines but I cannot think what these may be. Does anyone
> have any information on this?
There is a siddur Tzalusa DiAvraham that often documents when certain
parts of tfilah were incorporated into the liturgy. The Otzar Hatfilos
also often provides similar information.
Yitzchok Kahn
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From: Jay F Shachter <jay@...>
Date: Tue, 23 Sep 2008 21:21:46 -0600 (CDT)
Subject: Re: Palestinian Talmud
In mail.jewish v55n87, David Ziants <dziants@...> wrote:
> > letter "hé". Our sages have taught us (Palestinian Talmud, Tractate
> > Sanhedrin, Chapter 9, Halakha 6) that this paired change illustrates the
>
> "Jerusalem Talmud" please...
"Jerusalem Talmud" is just wrong. It was not composed anywhere near
Jerusalem, a pagan city where Jews were not even allowed to live, much
less operate academies. "Tiberius Talmud" would be more accurate.
"Palestinian Talmud" would be most accurate, since it was composed in
several different places that were all entirely within the Roman
province of Palestine, the naming of which had something to do with the
absence of Jews from Jerusalem.
What makes this topic interesting is that, although "Jerusalem Talmud"
is not a term used in respectable English-language scholarship, there
have been Hebrew-language sages, whose work is otherwise respectable,
who have used the corresponding Hebrew term (which can be transcribed as
"Talmud Yerushalmi"), rather than an accurate term such as "Talmud Eretz
Yisrael". My guess is that this originally arose out of nationalistic
reasons, a kind of Randle McMurphy-type act of rebellion ("you can
prevent Jews from living in Jerusalem, but you can't prevent us from
pretending that they do").
Jay F. ("Yaakov") Shachter
<jay@...>
http://m5.chicago.il.us
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From: David Maslow <maslowd@...>
Date: Tue, 9 Sep 2008 09:25:19 -0400
Subject: Plain Plane Geometry (was Value of Pi and Haredi Haskafa)
There has been some discussion on the list about the value of pi, the
relationship between the diameter of a circle and its circumference. An
example was given by Dr. Hendel (MJ56:31),
* "so for example if I sold a circular plot of land with 3000 square
feel I would by default have committed myself to a circular plot with
radius 1000
* (which would give the buyer 3142 square feet of land).
Regardless of the exact value of pi, the relationship between area and
radius is an exponential one, so that a circular plot with radius 1000
would have a circumference of about 6280 feet (pi times the diameter)
and an area of 3,140,000 square feet (pi times the radius squared).
David E. Maslow
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From: Michael Gerver <mjgerver@...>
Date: Fri, 26 Sep 2008 00:18:28 +0300
Subject: Protest against new Israeli policy on Sudanese refugees
I'm not sure if this is strictly within the purview of mail-jewish, but
this seems like an extremely important issue, and I hope Avi will allow
it. Certainly it does raise halachic questions.
My daughter Mollie, who is a student at Hebrew U and has been very
involved in advocating for Sudanese refugees in Israel, told me recently
that our Minister of Defence has adopted a new policy of forcibly
returning Sudanese refugees to Egypt as soon as they cross the border.
Although this new policy has not gotten much publicity, Mollie has
spoken to soldiers who have personally witnessed it on the Egyptian
border. Egypt is known to return these refugees to Sudan, where they
will likely be killed. There is a protest against this policy planned
for this Sunday, Sept. 28, at 5:30 pm, on Kaplan Street in Tel Aviv,
across from the Kiryah (Ministry of Defence headquarters). I hope that
our Israeli readers who share my concern about this will be there, and
that any readers who share my concern, whether they can be there or not,
will pass this information on anyone who might be able to come.
Please note that these refugees are very pro-Israel and
pro-democracy. In Sudan, they are being attacked by people with the same
jihadist ideology as the people who are attacking us. They are our
natural allies. There are striking parallels with the policies of the
US, the UK, and other Western countries, not allowing in Jewish refugees
during the Holocaust. Many of the arguments used to defend the policies
are the same: that the refugees are citizens of an enemy country and
might be spies; that they will take away jobs from citizens; that they
will be a burden on society that we cannot afford. All of these
arguments were wrong in the US and the UK in the 1940s, and they are
wrong in Israel now. On the contrary, the Jewish refugees during the
Holocaust would have been a valuable economic and social asset to the
Western countries that refused to take them in, creating many jobs. And
the Sudanese refugees, who have a lot of initiative and motivation to
succeed--after all, they risked being shot by Egyptian border guards to
get to Israel--will also be a net asset to Israel economically. Not to
mention their potential political value to Israel, when and if they
return to an independent southern Sudan or Darfur, where they will make
up the leadership of their country.
For more information, see www.plitim.org, and www.4asylum.org, although
these websites have not been updated recently--does anyone want to
volunteer to keep them up to date? For more recent information,
including letters from soldiers who have witnessed refugees being
returned to Egypt, those of you who are members of Facebook can look at
Mollie's Facebook page. You can get to it from my Facebook page, which
you can get to from the mail-jewish Facebook group.
Mike Gerver
Raanana, Israel
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From: Ben Katz <BKatz@...>
Date: Mon, 8 Sep 2008 09:21:37 -0500
Subject: RE: Value of pi
From: <chips@...>
>> 1) The Talmud based on a verse in Kings of a temple construction with
>> a diameter of 10 and circumference of 30 infers that the mathematical
>> constant pie is 3. Some authors have seen this as a "belief" or a
>> "Sanctioning" of pie as 3.
>
>It would have been obvious to anyone that pi # 3 without any major
>scientific breakthrough, as indeed it was as they simply took the actual
>measurements. So to me the explaination that pi = 3 was to be used for
>halachic purposes seems somewhat obvious and not an apolegetic at all.
>HOWEVER, what does bother is the continuation of the Gemara which
>discusses Shloma haMelech's bowl. After giving what is basically the pi
>= 3 measurements, there is then a complaint that the length measurements
>don't fit the volume measurements. And the Gemara does NOT answer that
>"pi = 3" is itself an approximation.
The gemara and even the medieval tosafists were unaware of even
relatively basic geometry. They use relatively crude mathematical
proofs to calculate things such as the area of circle.
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End of Volume 56 Issue 47
