[Avodah] electricity on shabbat

[Micha Berger]

On Wed, Jan 06, 2010 at 03:09:52PM +0200, Ben Waxman wrote:
: I thought that to be a psik reisha, first of all it has to be 100% (100% of 
: all chickens who have their head cut off will die) and the melacha 
: performed has to be a direct result of the action.

I doubt it has to be exactly 100%. E.g. I don't think Mike the Headless
Chicken (who lived for four years in the 1940s on the reflexes provided
by his spinal chord) disproves the textbook case of pesiq reishei.

Nearly always is close enough. And I believe that a 110v wall switch
sparks in that range. If the switch is overloaded, they'll get away from
the small area designed for them, and you might see the spark through the
crack around the plastic you just flipped, or you might smell ozone. In
which case, the switch needs replacing or plug in that high wattage
device elsewhere -- venishmartem me'od lenfashoseikhem.

But the speaking on the small but still visible scale is normal. Only
poses a threat if ch"v there is a gas leak.

RNSlifkin invokes poor Mike to explain about the Stincus marinus, which
had scales but no fins, despite the gemara saying that every fish with
scales had fins, and you didn't really need to check both simanim:
    Rabbi Yonasan Eybeschitz and Rabbi Yaakov Tzvi Mecklenburg (in HaKesav
    VeHaKabbalah), however, proposed a simple explanation. ... This is
    the explanation that Rabbi Eybeschutz gives...: "It seems that this
    is with the majority of fish. For with everything -- and especially
    with the nature of creatures -- it always follows the majority. With
    all creatures there are many things that are exceptions from the
    usual nature, as the naturalists have attested regarding the nature
    of animals. But the Torah and mitzvos all implement the principle
    of following the majority, and the majority of those that possess
    a scale, have a fin."

Tir'u baTov!
-Micha

-- 
Micha Berger             The fittingness of your matzos [for the seder]
micha at aishdas.org        isn't complete with being careful in the laws
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