Bava Batra

If a man wants to build a wall alongside of his neighbour's wall, he must not do so unless he keeps it [at least] four cubits away. Raba strongly objected to this, on the ground that it says. IF A MAN [ALREADY] HAS A WALL RUNNING ALONGSIDE OF HIS NEIGHBOUR'S WALL. No, said Raba: what it means is this: If a man had a wall running alongside of his neighbour's wall at a distance of four cubits and it falls down, he must not bring another wall alongside unless he keeps it four cubits away,  the reason being that the treading of the earth between [by foot passengers] is good for the walls [on both sides]. Rab said: This Mishnah applies only to the wall of a vegetable garden,  but [if] the wall [is that] of a courtyard, he may bring [his wall] as close to it as he likes. R. Oshiah, however, said: It makes no difference whether it is a vegetable garden or a courtyard. he must not bring his wall closer to it than four cubits. R. Jose b. Hanina says: There is no conflict between Rab and R. Oshiah; the former speaks of [a courtyard in] an old town  and the latter of [one in] a new one. We learnt: IF THERE ARE WINDOWS [IN THE NEIGHBOUR'S WALL] HE MUST LEAVE A CLEAR SPACE OF FOUR CUBITS, WHETHER ABOVE OR BELOW OR OPPOSITE; and in a Baraitha commenting on this it is stated that a space must be left 'above' so that he should not be able to peep into the other one's room, and 'below' so that he should not stand on tiptoe and look in, and opposite' so that he should not take away his light. The reason then [why the second wall must be kept away from the first] is that he should not take away his light. and not, as you say, that the ground between should be trodden?  — Here [in the Baraitha] we are dealing with a wall which runs at right angles to the first wall. How far [must such a wall be kept away so as not to take away the other's light]?  — R. Yeba the father-in-law of Ashian b. Nidbak said in the name of Rab: The breadth of a window. But cannot he still look through?  — R. Zebid says: We presume that he makes the top of the wall slope.  But does not our Mishnah say. [at least] four cubits? — There is no contradiction: in the one case the wall running at right angles is on one side [only of the window].  in the other [there are walls at right angles] on both sides [of the window].  Come and hear: The wall must be kept away from the [neighbour's] roof-gutter four cubits, so as to allow room for setting a ladder.  The reason, it appears, is that there may be room for a ladder, but not that there may be room for treading? — Here we are dealing with an overhanging gutter,  where there is no need to make allowance for treading, because there is room to walk under the gutter. MISHNAH. A LADDER MUST BE KEPT AWAY FROM A PIGEON COTE FOUR CUBITS SO THAT A WEASEL SHOULD NOT BE ABLE TO SPRING [FROM THE LADDER ON TO THE COTE]. THE WALL MUST BE KEPT FOUR CUBITS FROM THE [NEIGHBOUR'S] ROOF-GUTTER SO AS TO ALLOW ROOM FOR SETTING A LADDER. GEMARA. Shall I say that the Mishnah does not concur with R. Jose. who has laid down that 'the one may dig [a pit where he likes] in his property. and the other may plant [a tree where he likes] in his property'?  — You may say that even R. Jose would concur with the Mishnah here. For R. Ashi has told us that 'when we were with R. Kahana, he said to us that R. Jose admitted that a man was responsible for the damage of which he is the cause.'  Here too, it may happen that while the man is setting the ladder the weasel is sitting in a hole close by and jumps on to it. But here he is merely the indirect cause? Said R. Tobi bar Mattanah: This is equivalent to saying that it is prohibited to cause damage indirectly, [even where the damage, if caused, need not be paid for]. R. Joseph had some small date trees