OPINIONS: The Gemara records a dispute between the Rabanan and Rebbi Yosi. The Rabanan maintain that a person may not place harmful objects in a place where they might damage his neighbor's property, while Rebbi Yosi maintains that it is the neighbor's responsibility to protect himself from damage and it is not the responsibility of the potential Mazik to avoid the damage. Rav Ashi teaches that even according to Rebbi Yosi, one may not place a harmful object that causes damage in the manner of "Girei Dilei" -- "his arrows," or damage caused directly by his act of placing the harmful object there.

The Halachah follows the opinion of Rebbi Yosi (as the RIF and ROSH write, based on the Gemara in Bava Basra 25b) who says that one is not obligated to distance his harmful objects from his neighbor's property unless the objects cause damage in such a way that they are considered "Girei Dilei." What defines an object as "Girei Dilei," which prohibits the owner from placing it within a certain range of his neighbor's property?

(a) RASHI in Bava Basra (22b, DH b'Girei) writes that "Girei" is defined as any damage which comes directly from the Mazik himself. In the case of the Gemara here, if one spills water which flows directly down to the property of the lower neighbor, it is considered the "Girei" ("arrows") of the upstairs neighbor since it comes directly from his hands. If it stops before it drips down, it is not considered to come directly from the Mazik's hands and it is not "Girei."

(b) The RI MI'GASH in Bava Basra (22b) and the ME'IRI here define "Girei" as damage which occurs immediately when the harmful object is put in its place. If there is a delay between the time that the object is placed there and the time that the damage occurs, it is not considered "Girei." In the case of the Gemara here, if the water drips down without stopping, the damage is considered to be immediate and it is "Girei Dilei," but if it does not flow downwards immediately (for example, it becomes absorbed in the ceiling beam, and afterwards it drips down), the damage is not considered to occur immediately and thus it is not considered "Girei."

(c) The RAMBAN in Bava Basra (22b, DH Leima) defines "Girei" as damage which comes directly from the location at which the object is placed, even if the damage does not occur immediately when the object is placed there.

(d) A fourth opinion is that of RABEINU YONAH (Bava Basra 18b). In order for damage to be considered the "arrows" of the Mazik, the damage must occur immediately at the time that he puts the object in its place, and it must come directly from the location where the object is placed. Rabeinu Yonah requires both of the above conditions (that of the Ramban and that of the Ri mi'Gash) in order for the damage to be considered "Girei Dilei."

QUESTION: The Mishnah teaches that when the owner of the second floor requests from the owner of the ground floor to rebuild his house and the ground floor owner refuses, the second floor owner is permitted to rebuild the ground floor himself. He may then live in it until the ground floor owner reimburses him for his expenses.

Why must the owner of the second floor get involved in such a complex procedure? Why can he not simply ask Beis Din to force the ground floor owner to either rebuild or pay for the rebuilding? Why is this case different from any other case in which Beis Din forces a person to pay when he has monetary obligations? (RAMBAN)

ANSWER: The RAMBAN cites the Yerushalmi which asks that there seem to be two contradicting Beraisos. One Beraisa says that Beis Din forces the ground floor owner to rebuild, while another Beraisa says that he is not forced to rebuild. The Yerushalmi answers that when the ground floor owner is present Beis Din forces him to rebuild (or to pay), but when he is not present (for example, he left the country) Beis Din does not forcibly collect the funds from his property.

The Ramban explains that the Mishnah here also refers to a case in which the ground floor owner has left the country and it is not possible to collect from him.

Why, though, may Beis Din not collect from his property even if he is not present? The Gemara in Kesuvos (88a) quotes Rav Nachman who says that when a debtor has gone abroad, Beis Din may collect the debt from his property in his absence. Why does Beis Din not do so in the case of the fallen house?

The TOSFOS YOM TOV here offers two answers. First, he suggests that the obligation of a ground floor owner to the owner of the second floor is not comparable to a borrower's obligation to pay a lender. The obligation of the ground floor of a house to support the second floor is an obligation of the house itself and not an obligation of the owner. That is, as long as the ground floor exists, it is Meshubad, so to speak, to support the second floor. When the ground floor no longer exists (because it collapsed), the owner has no obligation to rebuild it in order to support the second floor. The obligation of a borrower to pay the lender, in contrast, is a monetary obligation that is incumbent on the borrower himself. This is the answer of the RASHBA.

The Tosfos Yom Tov offers an alternative answer. Rav Nachman in Kesuvos allows Beis Din to collect a debt in the debtor's absence only when the debt results from a loan. In such a case, the Chachamim instituted that Beis Din may collect in the debtor's absence so that lenders will not be reluctant to lend money (out of fear that the borrower will leave the country and they will be unable to collect the debt). For any other form of debt, the Chachamim did not institute that Beis Din may collect in the debtor's absence. (Y. MARCUS)