ANSWERS TO REVIEW QUESTIONS
prepared by Rabbi Eliezer Chrysler
Kollel Iyun Hadaf, Jerusalem
Previous dafEruvin 25
ERUVIN 25 -sponsored by a generous grant from an anonymous donor. Kollel Iyun Hadaf is indebted to him for his encouragement and support and prays that Hashem will repay him in kind.
(a) Planting trees in a Karfaf which is more than a Beis Sasayim will not
permit carrying inside it - since it is normal to plant trees in a Karfaf,
so that the status of the initial wall will not have been changed.
(b) Sticking a board ten Tefachim high and four by four Tefachim in the
ground (anywhere in the area - even in the middle) of the Karfaf - will
reduce it to a Beis Sasayim to permit carrying there.
(c) Rabah permits even a board of *three* Tefachim or more - because
anything which is three Tefachim or more leaves the realm of Levud.
(Consequently, the two ends of land are no longer considered still joined).
(d) According to Rava - it will be forbidden to carry there, unless the
plank is at least *four* Tefachim long - because four Tefachim is considered
a Makom Chashuv (as we learnt repeatedly with regard to the Din of the
Reshuyos on Shabbos).
(a) When a second wall is built inside one of theoriginal walls of a Karfaf
that is more than a Beis Sasayim - Rabah permits carrying there provided the
second wall is at least *three* Tefachimdistant first - since it
has left the realm of Levud; whereas according to Rava, even at a distance
of under *four* Tefachim it is Batel to the first wall, and is not
considered important to detract area of more than Beis Sasayim.
(b) The question of the second wall being less than three Tefachim
first, cannot be speaking about detracting from more than a Beis Sasayim -
because, if it was, then it would not be any worse than thick plaster added
to the wall, which we shall soon see, *does* detract excessive
area. In fact, explains Rashi, we are speaking about an area that remains
more than a Beis Sasayim, and the point in question is about turing the
Karfaf into one which is 'Pasach ve'li'be'Sof Hukaf'.
(c) According to Rav Shimi - Rabah and Rava agree that a three Tefachim Amud
will detract from more than a Beis Sasayim, and a second wall three Tefachim
distant first, is a Mechitzah. Their dispute concerns an Amud which
is less than three Tefachim in length, and a wall less than three Tefachim
distant first: in both cases Rabah will be lenient even *there*.
(d) Rabah and Rava both agree that if one smeared a thick layer of cement
(that would have stood even if it had not been attached to the wall) on to a
wall surrounding an area that was more than a Beis Sasayim - the extra layer
will detract excess area, and that one may therefore carry there.
But if only a thin layer of plaster (which could not have stood without the
wall) was added - Rava maintains that it does not detract wall, and
one may not carry there; whereas Rabah permits carrying even *there*.
(a) If one side of a Karfaf which is far in excess of a Beis Sasayim is a
raised mound of earth - everyone will agree that one may turn it into a
Hukaf le'Dirah - by building a wall parralel to it at a distance of four
Tefachim from it.
(b) Rav Chisda concedes - that building a wall on top of a wall in the
property of a Ger who died (and who leaves no heirs) is ineffective, and
that, somebody who does so, will not acquire the property.
(c) And Rav Sheshes concedes - that building a wall on top of a wall will be
effective, if one builds it on top of a mound which is more than a Beis
Sasayim. This is because the wall is now effective to turn the mound into a
Hukaf le'Dirah, in which we will say 'Migu' - i.e. since the wall is
effective for the people on top of the mound, it will also be effective for
those living below, to turn the area into one that is now Hukaf le'Dirah..
(a) If someone builds a wall on top of a wall after the death of the Ger to
whom it had previously belonged, he will not acquire that piece of land -
even if the lower wall subsequently sinks into the ground - because at the
time that he made the Chazakah (built the wall), he did not acquire it
(since it was then a Mechitzah on top of a Mechitzah); later, when the lower
wall sunk into the ground, he did not make a Chazakah, but now wants to
acquire the property automatically in retrospect - and one cannot acquire
the property of a Ger retroactively.
(b) However, if the lower wall sunk into the ground on Shabbos - one will be
permitted to carry there, because a Mechitzah that comes into existance
automatically, is considered a Mechitzah.
(c) When Rav Nachman said about a wall that was built on Shabbos 'Aval
Letaltel, Asur' - he was referring to someone who built it on purpose, but
not in a case such as ours, where it came into existance automatically.
(a) The reason that Rebbi Zeira permits carrying in an area of three Sa'ah,
of which one Sa'ah was covered - is because he holds of the principle 'Pi
Tikrah Yored ve'Sosem', whereas Rabah does not hold of it here (for reasons
that will be explained immediately).
(b) Yes, Rabah could well hold like Rav - who says 'Pi Tikrah Yored
ve'Sosem'. However, that is only by a roof which is parallel to the ground,
at a hundred and eighty degrees, whereas our case speaks by a slanting roof,
and it is *there* that Rabah disagrees with Rebbi Zeira.
(a) When Rebbi Yosef asked Rebbi Zeira 've'Chi Avir ha'Mutar Lo, Asro' - he
meant to ask how it is possible for the air of an area where one is
permitted to carry, to transform the Karfaf from an area which is permitted
to one which is forbidden?
(b) Rav Chisda confined his statement (that if a Karfaf opens completely
into a Chatzer (whose walls extend on both sides beyond the width of the
Karfaf), one may carry in the Chatzer, but not in the Karfaf) to the
*Karfaf* that opens completely into the *Chatzer*, and not the reverse -
because the reason that carrying in the Karfaf is forbidden is because the
space of the Chatzer adds to that of the Karfaf, making it more than a Beis
Sasayim, and rendering it Asur (even though the Chatzer itself is
permitted). In the reverse case, the Chatzer would not become forbidden due
to the added space of the Karfaf. Why not? Because a Chatzer of more than a
Beis Sasayim remains permitted in all cases, since it is Hukaf le'Dirah.
(c) This proves that Rav Chisda holds like Rebbi Shimon (according to whom
the Chatzer and the Karfaf are considered as one Reshus - because if he were
to hold like the Rabbanan, then the reason that carrying is forbidden in a
Karfaf which opens fully into a Chatzer, is because, any Reshus which opens
fully into another Reshus is considered as if it was lacking a wall. In that
case, what is the difference between a Karfaf that opens fully into a
Chatzer, or a Chatzer that opens fully into a Karfaf? Both should be Asur?
(d) In any event, we see that even according to Rebbi Shimon, the Chatzer,
which is itself permitted, nevertheless adds to the space of the Karfaf, to
make it more than a Beis Sasayim and to forbid carrying there - like Rebbi
Zeira's contention, and not like Rav Yosef's Kashya.
(a) Rav Bibi wanted to permit carrying in that orchard which adjoined the
house, when the adjoining wall collapsed - on the grounds that the three
remaining walls of the house could now also double as walls for the orchard.
(b) When Rav Papi referred to Rav Bibi as Mula'i - he meant that, as a son
of Abaye, he descended house of Eli, who were all 'cut off' (the
literal meaning of 'Mula'i), because, as a rule, they all died before they
reached the age of twenty.
(c) Rav Papi objected - on the grounds that the three remaining walls of the
house were built to protect the *inside* of the house, and could not
therefore double as walls for the orchard *outside*.