Reference for Bava Batra 44:13

רב יוסף הוה ליה הנהו תאלי דהוו

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.<span class="x" onmousemove="('comment',' In case he wants to climb up to the gutter to clean it. V. next Mishnah. [This interpretation follows Rashi; for other explanations, v. H.M. Tur and Beth Joseph 154.] ');">¹²</span> 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,<span class="x" onmousemove="('comment',' Which projects from the roof over the neighbouring courtyard. ');">¹³</span> where there is no need to make allowance for treading, because there is room to walk under the gutter. <b><i>MISHNAH</i></b>. 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.<span class="x" onmousemove="('comment',' V. p. 113. n. 7. ');">¹⁴</span> <b><i>GEMARA</i></b>. 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'?<span class="x" onmousemove="('comment',' Whereas here the man may not place the ladder where he likes in his own property. V. infra 25b, and supra 17b. ');">¹⁵</span> — 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.'<span class="x" onmousemove="('comment',' Lit., 'for his arrows', i.e., for damage resulting from an action which is in itself legitimate. ');">¹⁶</span> 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

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