bm 29a.1: We begin on last line of 28b, citing our mishna:
"What is to be done with the money (the proceeds of selling the nonproductive animal)? R. Tarfon says the finder may use it."
They [R. Tarfon, who says the finder may use it, and R. Akiva who says he may not] did not disagree except if he used the money; if he did not use the money (they would agree that) if he lost it, he is not responsible.
[The disagreement is really on whether the finder has the _right_ to use the money. According to R. Tarfon, the finder does have this right; therefore, as a paid custodian, he is responsible if the money is lost. But according to R. Akiva, the finder does not have the right to use the money; he is an unpaid custodian, and it is a talmudic principle that unpaid custodians are not responsible except for negligence. However -- and this is critical for the next bit of analysis -- both R. Tarfon and R. Akiva a re dealing only with the use of the money, not of the lost item itself.]
Shall we say that this is a refutation of Rav Yosef's view [that the finder _can_ use a lost item], for we have said: The custodian of a lost item: Rabba says he is an unpaid custodian [and not responsible for loss], and Rav Yosef says he is a paid custod ian [who _is_ resonsible for loss]. [Rav Yosef's position is based on the principle that a person engaged in one mitzva is exempt from others. For example, if a person in the midst of the mitzva of prayer is exempt from giving tzdaka. In the present case, when one is guarding the lost item, he is engaging in a mitzva, and would be exempt from giving tzdaka; that is enough of a benefit to have Rav Yosef characterize the finder as a paid guardian. But the exemption is only when one is actively engaged in on e mitzva to such an extent that one cannot concurrently engage in another mitzva. A man fulfilling the mitzva of wearing tzitzit is not exempt from the mitzva of tzdaka, since they are not mutually exclusive. Therefore, Rabba rules that the finder is an u npaid custodian; he cannot exempt himself from tzdaka because he has a lost item in the closet waiting for the claimant.]
Rav Yosef would say to you: Everyone (both R. Tarfon and R. Akiva) agrees that, the finder is responsible for theft and loss (of the item, because the finder is a paid custodian). Where they disagree is with respect to loss by _accident_, for which a borr ower is liable [i.e., if I borrow your tools and they break accidentally, I must pay for them].
[We have translated "onsin" as "accident", but is a broader term, covering various consequences of _force majeure_: unavoidable accidents (a donkey breaks a leg while plowing), "acts of God" (the barn is struck by lightning), armed robbery, or expropriati on by governmental agents, etc...]
(Rav Yosef's interpretation:) R. Tarfon says that the rabbis allowed the finder to use the money, and he is like a borrower. R. Akiva holds that the rabbis did not permit the finder to use the money; therefore, he is not a borrower (but remains a custodia n, who is not liable for accidental loss).
[Therefore, since the argument between R. Tarfon and R. Akiva was about whether, _after the sale of the lost object_, the holder or the money becomes a borrower or remains a custodian, it is irrelevant to Rav Yosef's difference of opinion with Rabba about the finder's status _before the sale of the lost object_: whether he is to be regarded as a paid or an unpaid custodian].
The gemara questions Rav Yosef's explanation: If so [i.e., if it is a question of liability for accidental loss], why did R. Akiva have to say "Therefore (if the money is stolen or lost he is not responsible)?"
If you say that they (R. Tarfon and R. Akiva) disagree with respect to theft and loss (responsibility for which distinguish a paid custodian from an unpaid one), I can understand why the mishna says "R. Akiva says he may not use the money, therefore if it is lost he is not liable". Otherwise, you might have thought that he is a paid custodian [of the money, as he was of the lost item before the sale] like Rav Yosef's opinion, and would be responsible for its theft and loss. The "therefore" phrase is to te ll us that now that you have ruled that he cannot use the money, he is not a paid guardian, and is not liable for theft and loss.
But if you say (as Rav Yosef suggests) that everyone agrees that he is responsible for theft and loss, and the disagreement is only with respect to the borrower's liability for accidents, what does (R. Akiva's) "Therefore" phrase teach us? The mishna _sho uld_ have said "R. Akiva says he cannot use the money," and I would have known that since he cannot use the money, he is not a borrower, and he is not responsible for it (if it is lost). Why, then, is R. Akiva's "therefore" clause needed?
The gemara answers: [The clause really is not needed, except for parallelism with] R. Tarfon's "therefore" clause.
And why is R. Tarfon's "therefore" clause needed? This is what he was saying: Because the rabbis permitted the finder to use the money, it is as if he used it [even if he actually had not done so] and he is liable for accidents.
But the mishna says "lost" [so how can Rav Yosef interpert the mishna as referring to an accident]?
It is according to Rabba, as Rabba said, stolen means stolen by an armed robber, and lost means a ship lost at sea. [Rabba -- and Rav Yosef -- thus define an unavoidable loss as an _accident_, for which a borrower is liable.]
Rav Yehuda said in the name of Shmuel: Halakha is according to R. Tarfon (and the finder may use the money).
Rachva was a custodian of money belonging to orphans. He came to Rav Yosef and asked "Can I use the money?" Rav Yosef said "This is what Rav Yehuda said in the name of Shmuel; halakha is according to R. Tarfon (i.e., a custodian _can_ use the money.
Abbaye said (to Rav Yosef): But hasn't (the following) been said about (this halakha)?: Rav Chelbo said in the name of Rav Huna: It (the rule that the finder can use the money) applies only to the proceeds of the sale of a lost item, since the finder took trouble (to care for it before selling it), but (appropriately identifiable) lost coins, with which he took no trouble [except to lock them away in his cupboard], he may not not use them. Aren't the orphans' money like lost coins (in this respect)? [Obvi ously they are, so why permit their use?]
Rav Yosef said the Rachva: Go, they do not allow me to permit this to you (i.e., Rav Yosef admitted that Abbaye's analysis was correct.
[We are now at the mishna on 29b.]