1) AN ANCIENT LOST OBJECT
QUESTION: The Gemara explains that one may keep an object that he finds in an old wall when the object is very rusty. The rust shows that it does not belong to the present owner, and therefore the finder may claim that the object was left there from the times of the early Amorites and is not of Jewish origin.
However, even if it is possible that the object is from the Amorites, there certainly exists a possibility that it was lost by a Jew! Even if that Jew died, the object belongs to his heirs. It is true that the heirs would have had Ye'ush had they known that the object was lost. Nevertheless, since they may not have been aware that their father had such an object, it should be considered "Ye'ush she'Lo mi'Da'as."
ANSWER: The TORAS CHAIM states that the object indeed might have been lost by a Jew. However, since there is a possibility that it is from the Amorites, the finder is permitted to keep it due to the doubt about its true origin. (Since the object is not in the possession of its owner, the owner does not have a Chazakah on it, and the finder may keep it. See Tosfos to 23a, and Insights to 21:1.)
The answer of the Toras Chaim indicates that, in general, a person may keep a Safek Aveidah. However, the Gemara later (26b) seems to contradict this. The Gemara later discusses a Sela that was lost by one of three people who are walking together. The Gemara rules that if the coin found is worth even two Perutos, the finder may not keep it. The Gemara is concerned that all three may have owned the coin jointly, and one of them relinquished his share to one of the other two partners, in which case the Aveidah would be worth a Perutah to the one who lost it. If they are partners, they would trust each other and assume that one of them must have found it and will return it later, and therefore they would not have Ye'ush. Since a possibility exists that the owner did not have Ye'ush, the finder is not permitted to keep the coin. However, according to the Toras Chaim's opinion, why would the Rabanan make such an assumption to prevent the finder from keeping the coin? This case should be considered at least a Safek, and the finder should be permitted to keep the coin due to that doubt.
This difficulty may be resolved based on the interpretation of TOSFOS (DH she'Nafal) who explains that the Gemara is referring to a case in which the three people began to look for the coin together. The fact that they looked for it together shows that they trust each other. The coin, therefore, is not even considered a "Safek Aveidah"; rather, the Halachah assumes that they certainly did not have Ye'ush.
However, RASHI earlier (24b, DH Mi) seems to contradict the Toras Chaim's opinion. The Gemara there states that the Rabanan (who argue with Rebbi Shimon ben Elazar) do not permit a person to keep an object found in a place populated mostly by Kena'anim, and Rashi explains that the Rabanan do not follow the principle of "Rov" with regard to monetary matters. This implies that Rashi disagrees with Tosfos (at least with regard to the Rabanan's opinion) and maintains that the Chezkas Mamon of the original owner does not allow the finder to keep an Aveidah, even if it is a Safek Aveidah. If the Toras Chaim's explanation of the Sugya is correct, then it would seem that the Halachah of the Mishnah is true only according to Rebbi Shimon ben Elazar.
Perhaps Rashi understands the Halachah of the Mishnah differently. When the Gemara answers that the object is rusty, Rashi may interpret this to mean that since the object was left there for so long, the finder may assume that the owner certainly has forgotten where he left it and had Ye'ush already. It is not considered "Ye'ush she'Lo mi'Da'as" because if an object was placed intentionally in a particular place by its owner, it is assumed that the owner will remember it shortly thereafter (see Chart #8, footnote 8a). Since the object is rusty and clearly has been in the wall for a long time, the finder may assume that the owner is already aware of his loss.
2) ONE WHO PICKS UP A LOST COIN BEFORE "YE'USH"
QUESTION: Rava rules that if a person sees a Sela fall from someone and he picks it up with intention to steal it before the owner notices his loss and has Ye'ush, he transgresses three Mitzvos.
A Sela is an object that cannot have a Siman. Rava himself maintains that "Ye'ush she'Lo mi'Da'as" is Ye'ush. Why is the finder not permitted to keep the coin even if he picks it up before Ye'ush?
(a) The RAMBAN writes that the proper Girsa is "Amar Rabah" and not "Rava."
(b) The RASHBA and PISKEI RID write that the correct Girsa in the Gemara is "if one sees a Sela fall from two people." (This is the Girsa which Rashi here rejects.)
(c) RASHI seems to understand that Rava eventually retracted his position with regard to "Ye'ush she'Lo mi'Da'as" and agreed with Abaye that it is not Ye'ush. Rava follows that ruling here. This is evident from Rashi earlier (DH Nakitna), where Rashi discusses a statement that is later elucidated by Rava, but Rashi explains it according to the opinion of Abaye that "Ye'ush she'Lo mi'Da'as" is not Ye'ush.
TOSFOS (DH she'Nafal) questions Rashi's explanation and notes that it is not logical to assume that Rava changed his position. This is, however, what Rashi seems to maintain.
(d) TOSFOS RABEINU PERETZ and the RITVA explain that the coin that fell was in a wallet, and the wallet had Simanim. Since the owner relies on the Simanim of the wallet, he will not have Ye'ush.
3) COINS FOUND IN A STORE
QUESTION: The Mishnah teaches that when a person finds coins in a store he may keep them.
Why should the money not be acquired immediately by the storeowner? The Gemara earlier (11a) states that a person's Chatzer acquires an object for him even if he does not know that the object is there, as long as he is standing next to his Chatzer. Since the storeowner is in the store, his Chatzer (the store) should acquire the lost coins for him before anyone picks them up. (TOSFOS to 26a, DH d'Shasich)
(a) TOSFOS answers that a Chatzer does not acquire an object for the owner of the Chatzer when it is possible that the owner will never find that object. Since coins are small (and they could become lost in the dirt), it is possible that the owner will never find them and thus his Chatzer cannot acquire them for him.
(b) The RAMBAN, RASHBA, ROSH and other Rishonim give another reason. They explain that at the moment that the coin landed on the floor, the owner of the coin did not know that he lost it (he had not yet felt that it was missing from his pocket). At that moment, the storeowner could not acquire the lost coin. Even though the owner later has Ye'ush, his later Ye'ush does not remove the obligation of the storeowner to return the coin. Any lost object that enters a person's domain before Ye'ush cannot become his when its owner has Ye'ush, as the Gemara explains in Bava Kama (66a; see also Bava Metzia 21b). (This is referred to as "b'Isura Asa l'Yadei.")
Why is it significant that the owner has Ye'ush after the object enters the domain of the finder? After all, if a person is Mafkir a lost object after it enters the domain of the finder, the finder may keep it. (See Gemara and Rashi to 27a, "Afkurei Mafkir Lehu.") Why should Ye'ush be any less effective in this respect than Hefker?
The MORDECHAI cites the MAHARAM MI'ROTENBURG who explains that such Ye'ush is not valid because it is considered like "Ye'ush b'Ta'us," mistaken Ye'ush. If the owner had known that the object had already entered the domain of a person who was able to return it, he would not have given up hope of retrieving it.
TOSFOS in Bava Kama (66a, DH Keivan) gives another explanation. Tosfos writes that "Ye'ush is not like Hefker." (Tosfos is explaining why Ye'ush does not enable a Ganav to acquire a stolen object that entered his possession in the manner of "b'Isura Asa l'Yadei." In such a case, the logic of the Maharam does not apply, since the Ganav does not intend to return it and the owner's Ye'ush is therefore justified.) What does Tosfos mean?
Tosfos might mean that Ye'ush does not remove the ownership of the object's original owner. Rather, it permits others to take the object from him. If an object enters another person's domain before Ye'ush (whether the object was lost or stolen), the owner of that domain becomes obligated to return the object to its owner. This obligation prevents him from taking possession of the object, since as long as it has an owner he is required to return it to that owner. In contrast, if the owner is Mafkir the object, then the object has no owner and is not subject to the Mitzvah of Hashavas Aveidah, and the finder may keep it.
Why does Tosfos here not give the same answer that the Ramban and other Rishonim give to the original question? Why does Tosfos not say that the storeowner cannot acquire objects that come into his hands "b'Isura"? (MAHARSHAL cited by the SHACH)
1. The SHACH and MAHARSHA explain that Tosfos wants to explain the Mishnah even according to Rava, who maintains that "Ye'ush she'Lo mi'Da'as" is considered Ye'ush. According to Rava, Ye'ush should occur even before an object reaches the floor. (However, it is possible that even according to Rava, "Ye'ush she'Lo mi'Da'as" does not take effect until the owner leaves behind the coin that fell on the floor. Prior to that point, he would not have Ye'ush if he knew the whereabouts of the coin.)
2. They answer further that Tosfos (DH Afilu) explains understands that the Mishnah refers to a place inhabited mostly by Nochrim. Hence, the object is Hefker from the moment that it falls.
3. REBBI AKIVA EIGER explains that an object in one's Chatzer is not considered to be "b'Isura Asa b'Yadei" since he is not yet obligated in the Mitzvah of Hashavas Aveidah. Rebbi Akiva Eiger points out that if a Chatzer is Koneh because it is like a Shali'ach, then it cannot obligate the owner to do a Mitzvah against his will, because "Ein Chavin l'Adam she'Lo b'Fanav." (If a Chatzer is Koneh because of "Yad," perhaps it can obligate him in Hashavas Aveidah even if it is not a benefit to him.)