1) A WINDOW WHICH OPENS INTO A NEIGHBOR'S PROPERTY
QUESTION: Rebbi Zeira states that a person is permitted to make a window in his wall that faces his neighbor's Chatzer, provided that he builds the window more than four Amos high, in which case he cannot peer out of it and cause Hezek Re'iyah to his neighbor. The Gemara says that the owner of the Chatzer is not entitled to stop the owner of the house from building the window, because of the principle of "Kofin Al Midas Sedom" -- Beis Din forces a person not to act in the way that the people of Sedom acted. Since the owner of the Chatzer loses nothing by his neighbor having a window there, he cannot stop his neighbor from building the window. Rebbi Ila'a argues and says that the owner of the Chatzer is entitled to stop the owner of the house from making the window. The Gemara initially assumes that the reason why Rebbi Ila'a maintains that the owner of the Chatzer may prevent his neighbor from building the window is that he maintains "Ein Kofin Al Midas Sedom" -- Beis Din may not force a person to allow others to benefit when he loses nothing as a result.
In what way is the window in the wall related to Midas Sedom? Midas Sedom applies to a situation in which others benefit from one person's property in a way that the owner of the property loses nothing. In such a case, it is possible that the owner may be entitled to stop the others from deriving benefit from his property even though it is not proper for him to do so. In contrast, in the case of the window, the person who makes the window derives no benefit from the property of the owner of the Chatzer. Why should the owner of the Chatzer be entitled to stop him from making the window, even if the Halachah is "Ein Kofin Al Midos Sedom"? (KETZOS HA'CHOSHEN 154:1)
ANSWER: The KETZOS HA'CHOSHEN and REBBI AKIVA EIGER (Teshuvos 1:141) answer that the Gemara views the airspace of the Chatzer as the property of the owner of the Chatzer. If a person uses that airspace by looking out of a window through the Chatzer, or by receiving the air or light that comes through the Chatzer, it is considered a use of the Chatzer itself. This reasoning is expressed by the RASHBA earlier (17b).
RAV SHACH zt'l in AVI EZRI (Hilchos Shechenim 3:3) and the BIRKAS AVRAHAM ask how can airspace be considered owned by the owner of the Chatzer? If the air blows through the Chatzer, it does not become the property of the owner of the Chatzer. Beis Din certainly does not say that when air blows through the Chatzer into the window of the owner of the adjacent house, or when the light shines through the Chatzer into the window, that the air or light becomes the possession of the owner of the Chatzer.
Perhaps the Rashba and the Acharonim mean that deriving benefit from the fact that the Chatzer has open space is considered usage of the Chatzer, since this is the purpose for which the Chatzer was built. If not for the rule of "Kofin Al Midos Sedom," a person who did not build a Chatzer should not be able to derive benefit from the Chatzer that his neighbor built unless he receives permission from the owner of the Chatzer. That is why the Gemara needs the principle of "Kofin Al Midos Sedom" in order to permit it.
2) THE TIME NEEDED FOR MAKING A CHAZAKAH ON THE USAGE OF SOMEONE'S PROPERTY
OPINIONS: The Beraisa discusses a case in which a person builds windows into his wall that open into the Chatzer of his neighbor. Rebbi Yishmael rules that the owner of the windows has a Chazakah if his neighbor is silent and does not protest immediately. Rebbi Chiya argues and says that a person cannot make a Chazakah by doing an act that could inconvenience someone else, even if the other person does not protest immediately. The RASHBAM explains that Rebbi Chiya requires a Chazakah of three years in order to support the claim of the Machzik that he received permission to make windows that open into his neighbor's property.
The Halachah follows the view of Rebbi Chiya. Accordingly, it seems that just as a Chazakah which proves the ownership of property requires three years of occupancy on the property, a Chazakah for using another person's property requires three years of usage. However, the Gemara earlier (6b) teaches that if a person rests his beams on his neighbor's wall for thirty days, he makes a Chazakah for using his neighbor's wall in such a way. The Gemara there continues and says that if the beams support the Sechach of his Sukah, then even after seven days he has a Chazakah. The Gemara there clearly implies that it is not necessary to have three years of usage in order to make a Chazakah. What is the difference between these Halachos?
(a) Although the RASHBAM here writes that three years are necessary in order to make this Chazakah, the Rashbam earlier (6a) writes (in a Hagahah in Rashi) that the Chazakah for using another person's property takes effect immediately. The TUR (CM 153) explains that the Rashbam maintains that when one gives permission to someone else to use his property for small forms of usage, it is not the practice to write a Shtar. Therefore, the Chazakah takes effect immediately if the owner does not protest, and the person using the property is believed to claim that he bought the rights to use the property for that purpose. In contrast, it is the practice to write a Shtar for large forms of usage, such as those mentioned in the Mishnah. Therefore, the Machzik may claim that he bought the rights to that usage only after he has used the property for three years; within three years the owner can demand to see the Shtar (see also Insights to 57a).
(b) The BA'AL HA'ME'OR maintains that three years are required to make any type of Chazakah, even a Chazakah of usage of another person's property. He explains that the Gemara earlier (6b) means that a person must use the property for thirty days in addition to three years.
Alternatively, the Gemara there is not discussing an actual Chazakah, but rather it is discussing the question of when the usage of a wall is considered proof that a person paid his share in building the wall, as RABEINU TAM explains (cited by Tosfos 6b, DH Hai). This is also the opinion of TOSFOS earlier (23a, DH v'Ha) and the ROSH there. (The RIVAM cited by Tosfos adds that it is not necessary for one to present any claim after he uses someone else's property for three years. The other Rishonim, however, do not accept this opinion. They require that the person present a claim (for example, that he bought the rights to use the property, or that the owner allowed him the usage of the property).)
(c) The GE'ONIM cited by the RAMBAN (Milchamos to 6a, and in Chidushei ha'Ramban to 57a and 59b) explain that the Chazakah for using someone else's property does not require three years (as the Gemara earlier (6b) implies). Even though Rebbi Chiya rules that the Chazakah is not immediate, he does not say that three years are necessary. Rather, as soon as the usage has been continued long enough that it would be expected for the owner to protest, the Machzik has made a Chazakah. In the case of the beam (6b), using the neighbor's wall for thirty days proves that he has permission to use the wall.
The Ge'onim add that it is not necessary to present a claim of purchase or a claim of Mechilah, in contrast to the opinion of the Rashbam. According to the Ge'onim, the Chazakah of usage inherently differs from a Chazakah of ownership. A person is more willing to be Mochel usage of his object than to be Mochel ownership of his object. The Chazakah required to use a person's object is necessary to prove that the owner presumably was Mochel since he owner did not complain. Therefore, the Machzik is not expected to have a Shtar, and he does not need three years for his Chazakah.