[Avodah] clawing of cats

[Eli Turkel]

I response to comments on areivim I quote from parts of Michtav MeEliyahu:

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The view of Rabbi Eliyahu Dessler. In a
footnote to Michtav Me-Eliyahu, Rabbi Aryeh Carmell, one of Rabbi
Dessler’s foremost students, writes as follows:

   I have seen fit to note here that which I heard explicitly from
Rav Dessler, zt”l, when he was asked about certain laws for which the
reasons that have been given for them are inconsistent with the
reality determined by scientists of later generations, and they are
now in the category of that which the Gemara asks in many places, “But
surely we see that it is not so!”

   Three examples were considered:

   - It is ruled that there is derusah with a cat and not with a dog,
and the Gemara gives the reason that a cat exudes poison from its
claws (Chullin 53a).

   - It is ruled that we may only knead matzos with water that has
been in our possession overnight, and the reason, according to several
Rishonim, is that at night the sun passes beneath the Earth and heats
up the springs (Pesachim 94b).

   - It is ruled that one may kill a louse on Shabbos because the
louse does not reproduce by way of cohabitation (but spontaneously
generates) (Shabbos 107b).

   Rav Dessler said that with these and similar cases the law is
never changed, even though the reason is not initially understandable
to us. Rather, we must firmly grasp the law with both hands, whether
for stringent or lenient ramifications.


   The reason for this, explained Rav Dessler, is that Chazal knew
the law as a tradition from earlier generations. They also knew from
experience that, for example, maulings by cats are more likely to
result in deaths than maulings by dogs, and that water drawn from
springs in the mornings are warmer. But with regard to scientific
explanations, it is not that the explanation mandates the law, but
rather the opposite: that the law mandates an explanation. The reason
given in the Gemara is not the sole possible reason. And if, on
occasion, they gave an explanation according to the scientific
knowledge of their day, we are obligated to search for other
explanations which establish the law on its basis according to the
scientific knowledge of our day.

   Thus I heard from Rav Dessler, zt”l. According to this principle,
we can perhaps say, for example, as follows:

   The poison of which Chazal spoke is poisonous matter which
accumulates under a cat’s claws from rotting remnants of flesh that
remain from earlier prey. Note that a cat’s claws differ to a dog’s
claws, in that a cat’s claws are composed of two sections, and when a
cat swipes in order to kill it extends its claws to penetrate into the
flesh, and when it withdraws them, some of the poisonous matter
remains, to cause damage. All of the particulars of this law are
thereby explained, for we find there: “Derusah is only with the front
legs, to exclude the hind legs; derusah is only with the claws, to
exclude the teeth; derusah is only when done intentionally etc.”; and
it is only when done in anger (Rashi, Chullin 52b, s.v. aval). All of
this is explained according to that which we have written.

   Similarly with water - we can easily explain why our water is
colder than that which is drawn from the well in the morning. During
the night, the air cools rapidly, and therefore the water that is in
our vessels also cools. But the ground cools at a slower rate, because
of the heat that has accumulated in it during the day (and is
insulated). Therefore, in the morning, the water that is drawn from
wells, which has been in the ground, is likely to be warmer than water
which has been standing in the night air.

   With regard to the matter of the louse, the explanation is a
little more difficult. However, it is a known principle that the
halachah only considers that which can be detected by the senses.
According to this, perhaps we can say that since the egg of a louse is
extremely small, so much so that at the time of the giving of the
Torah it could not be detected at all, the halachah does not consider

-- 
Eli Turkel