1)
If as Rava explains, our Mishnah is speaking even when the neighbor has not yet built a wall, what is the Tana coming to teach us when he rules ...
... 'Marchikin es ha'Gefes ve'es ha'Zevel ve'es ha'Melach ... mi'Koslo shel Chavero Sheloshah Tefachim ... '?
... 'Marchikim es ha'Zera'im ve'es ha'Machrishah ve'es Mei Raglayim min ha'Kosel Sheloshah Tefachim ... '?
... 've'es ha'Rechayim Sheloshah min ha'Shechev ... ve'es ha'Tanur Sheloshah min ha'Kalya ... '?
How will Rava explain the Mishnah which forbids Reuven to open a bakery, a dyeing-shop or a stable underneath Shimon's storehouse, implying that he would be permitted to do so, if the storehouse was not yet there?
What does the Mishnah add there with regard to a stable, that bears this out?
1)
If, as Rava explains, our Mishnah is speaking even when the neighbor has not yet built a wall, then, when the Tana rules ...
... 'Marchikin es ha'Geffes ve'es ha'Zevel ve'es ha'Melach ... mi'Koslo shel Chavero Sheloshah Tefachim ... ', he is coming to teach us - that all the things listed there intrinsically cause damage to a wall.
... 'Marchikim es ha'Zera'im ve'es ha'Machrishah ha'Machrishah ve'es Mei Raglayim min ha'Kosel Sheloshah Tefachim ... ', he is coming to teach us - that the wetness caused by these things (though it is not clear how this applies to plowing) causes damage to a wall.
... 've'es ha'Rechayim Sheloshah min ha'Shechev ... ve'es ha'Tanur Sheloshah min ha'Kalya ... ' - he is coming to teach us - that vibration and heat cause damage to a wall, too.
The Mishnah later forbids Reuven to open a bakery, a dyeing-shop or a stable underneath Shimon's storehouse, implying that he would be permitted to do so, if the storehouse was not yet there. Rava will attribute this to the fact - that whatever has to do with actual residence (including one's animals) is permitted as long as there is no-one who currently suffers from one's actions.
The Mishnah specifically adds - that if the stable preceded the storehouse, it is permitted (a clause that the Tana did not insert in any of the previous cases), bearing out what we just said.
2)
The Mishnah later forbids Reuven to plant a tree within four Amos of Shimon's field. What reason does the Beraisa give for this? What purpose do those four Amos serve according to the Tana of the Beraisa?
Why, according to Rava, is it not forbidden anyway, because of the roots of Reuven's tree that will spread into Shimon's field and damage his plants?
The Mishnah later permits Reuven and Shimon to plant trees right up to the wall that divides their fields, dispensing with the Isur of Kil'ayim. Why are we not concerned about the roots of Reuven's tree that will grow under the wall into Shimon's field.
In that case, how can the Tana say in the Seifa 'Hayu Sharashav Yotz'in be'Toch shel Chavero, Ma'amik Sheloshah Tefachim'? How did the roots cross the strip of rocky terrain?
2)
The Mishnah later forbids Reuven to plant a tree within four Amos of Shimon's field 've'es ha'Rechayim Sheloshah min ha'Shechev ... ve'es ha'Tanur Sheloshah min ha'Kalya ... ', to which the Beraisa adds - 'because of Avodas ha'Kerem' (the four Amos that are required to work with one's oxen and cart, plowing the vineyard and picking the fruit (and the same applies to an orchard).
The reason that it is not forbidden anyway, according to Rava, is - because the Tana is speaking in a case where there is a strip of rocky terrain dividing between the two fields, which prevents the roots from spreading across from Reuven's field to Shimon's.
The Mishnah later permits Reuven and Shimon to plant trees right up to the wall that divides their fields dispensing with the Isur of Kil'ayim. We are not concerned about the roots of Reuven's tree growing under the wall into Shimon's field - because there too, the Tana is speaking where there is a strip of rocky terrain that divides between the two.
When the Tana rules in the Seifa 'Hayu Sharashav Yotz'in be'Toch shel Chavero, Ma'amik Sheloshah Tefachim' - he is referring to a case where there is no strip of rocky terrain. That is where it is necessary to plant the roots three Tefachim deep.
3)
The Mishnah later teaches 'Marchikin es ha'Ilan min ha'Bor Esrim-ve'Chamesh Amah'. If, as Rava explains, the Tana is speaking even when there is no pit as yet in the second field, then what is the Tana coming to teach us?
If planting the tree is prohibited even before the pit exists, how will we explain the Seifa 've'Im Ilan Kadam, Lo Yikotz'. How did the tree get there?
3)
The Mishnah later teaches 'Marchikin es ha'Ilan min ha'Bor Esrim-ve'Chamesh Amah. If, as Rava explains, the Tana is speaking even when there is no pit as yet in the second field, the Tana is coming to teach us - that a tree's roots damage a pit as far as twenty-five Amos.
Even though planting the tree is normally prohibited even before the pit exists, the Tana writes in the Seifa 've'Im Ilan Kadam, Lo Yikotz' - because he is speaking where Reuven planted the tree before selling the piece of land next to it to Shimon, who now wants to dig a pit (like Rav Papa will explain shortly, with regard to a similar problem).
4)
The Tana Kama there states 'Marchikin es ha'Mishrah min ha'Yerek ... ', implying that if there would be no vegetables, it would be permitted to place the soaking-house next to his neighbor's field. How does Rava explain that?
Why does the Tana Kama forbid Reuven to plant his mustard-seeds next to Shimon's bees?
On what grounds does Rebbi Yosi permit it?
But if - as Rava explains, the Mishnah is speaking even before Shimon opened his aviary there (since it is forbidden to place a potential Mazik close to the Nizak's Reshus in anticipation of the Nizak pacing his article there), what does Rebbi Yosi mean? How can Reuven plant his mustard-seeds close to the place where Shimon might later place his aviary?
4)
The Tana Kama there states 'Marchikin es ha'Mishrah min ha'Yerek ... ', implying that if there would be no vegetables, Reuven would be permitted to place his soaking-house next to Shimon's field. According to Rava - the same will apply even if there are no vegetables there, and the reason that the Tana mentions the vegetables is to teach us that a soaking-house is harmful to vegetables.
The Tana Kama forbids Reuven to plant mustard-seeds in the vicinity of Shimon's bees - because they first eat the flowers of his mustard-seeds, and then, to neutralize the sharp taste, they consume their own honey (causing a loss to Shimon).
Rebbi Yossi permits it - because, he says, since the bees eat his mustard-seed flowers, Shimon is no less of a Mazik than Reuven is, so let him move his aviary.
Despite the fact that according to Rava, the Mishnah is speaking even before Shimon opened his aviary there (because it is forbidden to place a potential Mazik close to the Nizak's R'shus in anticipation of the Nizak pacing his article there) - Rav Papa establishes the Machlokes between Rebbi Yossi and the Tana Kama in a case where, at the time that Reuven planted his mustard-seeds, the entire field belonged to him, and he subsequently sold Shimon part of it. And it is in that section, close to Reuven's mustard-seeds, that Shimon now decides to place his aviary.
18b----------------------------------------18b
5)
Seeing as Rav Papa just established the Machlokes between Rebbi Yosi and the Rabanan (with regard to the mustard-seeds and the bees) where Reuven sold Shimon half the field only after he had planted his mustard-seeds, on what grounds do the Rabanan obligate Reuven to move his mustard-seeds?
What problem do we have with attributing Rebbi Yosi's ruling to the Sevara 'al ha'Nizak Le'harchik es Atzmo min ha'Mazik'?
If, as we therefore assume, Rebbi Yosi too, holds 'al ha'Mazik Le'harchik es Atzmo min ha'Nizak', why does Rebbi Yosi differentiate between the soaking-house and the vegetables (where he concedes to the Rabanan) and the mustard-seeds and the bees, where he argues with them?
How do the Rabanan counter Rebbi Yosi's argument? What do they say about ...
... the mustard-seeds?
... the leaves of the mustard plant?
5)
Despite the fact that Rav Papa just established the Machlokes between Rebbi Yossi and the Rabbanan (with regard to the mustard-seeds and the bees) when Reuven sold Shimon half the field only after he had planted his mustard-seeds, the Rabbanan nevertheless obligate Reuven to move them - because they hold 'al ha'Mazik Le'harchik es Atzmo min ha'Nizak' (even if the Mazik was there first).
The problem with attributing Rebbi Yossi's ruling to the S'vara 'al ha'Nizak Le'harchik es Atzmo min ha'Mazik' is - if that is so, why does he not argue in the other cases in the Mishnah too. (Why, for example, does he concede to the Rabbanan that Reuven must move his soaking house away from Shimon's vegetables)?
So we assume that Rebbi Yossi too, holds 'al ha'Mazik Le'harchik es Atzmo min ha'Nizak', and the reason that Rebbi Yossi argues in the case of the mustard-seeds and the bees (even though he concedes to them by the soaking-house and the vegetables) is - because the bees damage the seeds no less than the seeds damage the bees (as we explained above), which is not so in the other cases in the Mishnah.
The Rabbanan in countering Rebbi Yossi's argument, claim - that the bees do not damage the mustard-plant at all ...
... neither the seeds - which they cannot get to, and ...
... nor the leaves - which re-grow.
6)
What does Rebbi Yosi say about a case where Reuven plants a tree within twenty-five Amos of Shimon's pit?
What conclusion can we draw from there?
Then how do we explain Rebbi Yosi's ruling regarding the mustard-seeds and the bees?
What is he then asking them?
What did the Chachamim reply?
6)
Rebbi Yossi rules that, in a case where Reuven plants a tree within twenty-five Amos of Shimon's pit - he is not obligated to move it away, because he holds ...
... 'al ha'Nizak Le'harchik es Atzmo min ha'Mazik'.
To reconcile Rebbi Yossi's ruling regarding the mustard-seeds and the bees with his latter ruling - we establish that Rebbi Yossi is actually debating with the Rabbanan according to their own reasoning ('al ha'Mazik Le'harchik ... ' [even though he personally holds 'al ha'Nizak Le'harchik ... ']).
And he merely means to ask them - whether, according to their basic reasoning, they will not agree with him that, at least in the case of the seeds and the bees, Reuven ought to be Patur, for the reason that we cited.
To which the Rabbanan replied that the bees do not damage the mustard-seeds (as we explained).