QUESTION: The Gemara states that when a person gives wool and dye to a professional dyer, the dyer is not "Koneh b'Shevach Kli" -- he does not acquire the wool and dye by doing work to it that increases its value. Since he is paid as a hired laborer and not on the basis of the completed job (like a "Kablan"), he does not acquire the materials given to him.
Why, then, does the Gemara say that when a person gives wood to a carpenter to build a closet, the carpenter acquires the wood when he increases its value (by building the closet)? The carpenter adds none of his own material; he merely works with the wood that was given to him. He should be no different from the dyer who works with the wool and dye that was given to him. (RASHBA, TOSFOS RABEINU PERETZ)
ANSWER: The RA'AVAD cited by the Rashba writes that whenever no material is added to the original product to increase its value, and the only input is one of energy and skill, the skill which the craftsman invests into the material is considered a tangible contribution through which the craftsman acquires the object. However, when the increase in the value of the original material is accomplished with other materials (such as dye put into wool), those additional materials are viewed as the only contribution to the object, and the skill of the craftsman is not viewed as the contribution to the object.
It is not clear why the input of the skill of the craftsman is ignored when there is a tangible input involved. Perhaps the Ra'avad means to explain as the TOSFOS RABEINU PERETZ does. Tosfos Rabeinu Peretz explains that the craftsman's skill is always considered a contribution. However, when there is another input as well, such as the dye that colors the wool, the input of the craftsman is not able to acquire the object for him. (This may be related to the topic of "Zeh v'Zeh Gorem.")
Alternatively, perhaps building a closet from wood requires a greater input of skill since no other input is required. Dyeing wool requires less skill since part of the dyeing is accomplishing with the dyes. A craftsman acquires the object which he improves only when a great amount of skill is required, for otherwise he is considered a hired laborer.
This approach may explain the comment of RASHI (in DH li'Vetushi). Rashi writes that when a person is hired to step on a woolen garment in order to soften it and he is paid for each time he steps on it, he is considered a hired laborer and not a craftsman who makes an object. TOSFOS (DH d'Agrei) asks that he still should be considered a craftsman who is hired to complete a job, since each time he steps on the garment he performs his craft. Therefore, Tosfos explains (as Rashi explains in Bava Metzia) that the person is paid to step on the clothing whether or not it becomes softer as a result of his stepping on it.
Rashi here may understand, as mentioned above, that a person who performs a craft which does not require a large input of skill is considered a hired laborer and he cannot acquire the object b'Shevach Kli, by making an improvement to it.
Tosfos, on the other hand, may understand like Rabeinu Peretz that any time there is no input other than that of the craftsman, the craftsman acquires the object b'Shevach Kli.


QUESTION: Shmuel teaches that if an expert butcher is given an animal to slaughter and he makes it a Tereifah, he is obligated to pay for it because "he is a Mazik and a Poshe'a" (according to Rebbi Meir). The Gemara explains that Shmuel did not say merely that he is a Mazik, for that would imply that the butcher is Chayav only when he is paid to slaughter the animal, while in truth Rebbi Meir rules that the butcher is Chayav even when he is not paid to slaughter the animal.
RASHI explains that the reason why the word "Mazik" implies that he is Chayav only when he is paid is that a Mazik is Chayav for Onsin, for damages caused by uncontrollable circumstances (an "Ones"). This is because of the principle that "Adam Mu'ad l'Olam." If Shmuel obligates a butcher even if an Ones happens, then he must be discussing a butcher who is being paid to slaughter the animal.
Rashi's explanation is not clear. If a butcher is considered an Adam ha'Mazik, then why would one think that he is exempt from paying when he is slaughtering for free, without receiving any pay? He should be Chayav as an Adam ha'Mazik, whether or not he is being paid! (KOVETZ SHI'URIM)
If, on the other hand, a butcher is not considered an Adam ha'Mazik, then why should he be Chayav if the animal becomes a Tereifah due to an Ones, even when he is being paid for his services? Being paid should make him only a Shomer Sachar, who is Chayav for Geneivah and Aveidah (when the item is stolen or lost), but not for Ones! (TOSFOS HA'ROSH, cited by the Shitah Mekubetzes)
ANSWER: Rashi does not mean to explain that a butcher is considered an Adam ha'Mazik. Rather, Rashi is explaining that the butcher's obligation is like that of a Shomer. However, if Shmuel would call him just a Mazik, it would imply that just as an Adam ha'Mazik is responsible for damages that he causes b'Ones, so, too, the butcher is liable for damages that he causes b'Ones. Hence, he must be a Shomer Sachar and that is why he is Chayav for damages that are not caused by a Peshi'ah (negligence on the part of the Shomer) but even by an Ones (since a Shomer Chinam certainly is exempt from damages that are not caused by a Peshi'ah). That is why Shmuel adds that the butcher is considered a Poshe'a: even if he would be a Shomer Chinam he would also be Chayav.
Regarding why the butcher is Chayav for damages caused by an Ones if he is like a Shomer Sachar, the Rishonim write that Rashi is not using the word "Ones" to refer to damage that was totally out of the control of the butcher. Rather, the damage that the butcher caused is at most a mild Ones which is equal to Geneivah (when an object was stolen from the domain of the Shomer). Therefore, the Shomer Sachar who is Chayav for Geneivah is also Chayav for an Ones such as when an expert butcher ruins the Shechitah and causes the animal to become a Tereifah. (See RASHBA, TOSFOS HA'ROSH, TOSFOS to 27b, end of DH u'Shmuel; see also RASHI in Bava Metzia 82b, DH Yishava.)
Why does the principle of "Adam ha'Mazik" not make the butcher obligated to pay even for an Ones? Why is his obligation to pay only that of a Shomer and not that of an Adam ha'Mazik?
1. TOSFOS (27b, DH u'Shmuel, and in Bava Metzia 82b, DH v'Savar) explains that Adam ha'Mazik is not Chayav for all types of Ones. In fact, he has even fewer obligations than a Shomer Sachar. He is Chayav for an Ones only when it borders on Peshi'ah (such as Aveidah, losing the item), but not for an Ones that is further removed from Peshi'ah, such as Geneivah. A Shomer Sachar, on the other hand, is Chayav for both Aveidah and Geneivah. When a professional slaughterer makes an animal into a Tereifah, it is an Ones that is further removed from Peshi'ah, and it is in the same category as Geneivah. Therefore, the principle of "Adam ha'Mazik" cannot obligate him to pay; his obligation to pay can stem only from his obligation as a Shomer Sachar.
2. The RAMBAN (Bava Metzia 82b) writes that since the butcher is slaughtering the animal at the behest of the owner, he cannot be called an Adam ha'Mazik. Whenever a person works at the owner's request, he is not a Mazik but a Shomer.
QUESTIONS: The Gemara relates an incident in which a butcher slaughtered an animal and made it a Tereifah. Rebbi Yochanan told him that since he was not paid to slaughter it, he may exempt himself from paying for the animal if brings proof that he was an expert at slaughtering chickens. Rebbi Yochanan's ruling follows the principle mentioned earlier in the Gemara that a person who is not an expert is responsible for damages even if he took no money for slaughtering the animal. Since he knew that he was not an expert and not properly trained to slaughter, he should not have accepted to slaughter the animal in the first place.
There are a number of questions on this Gemara.
(a) Why did the butcher need to bring proof that he was an expert in order to exempt himself from payment? The principle of "ha'Motzi me'Chaveiro Alav ha'Re'ayah" should apply, and he should have been exempt from paying unless the owner of the animal could prove that he was not an expert. (RA'AVAD; see also KOVETZ SHI'URIM, and BEIS HA'LEVI 2:4:4 and 3:20:2.)
(b) Another reason why the butcher should not have been required to prove that he was an expert is the principle (Chulin 3b) that if an animal is found slaughtered, one may assume that the slaughterer was an expert because "Rov Metzuyin Etzel Shechitah Mumchin Hen" -- most people who are involved in Shechitah are experts. (SHACH YD 1:4)
(a) As explained earlier (see previous Insight), the butcher is considered a Shomer Chinam when he receives no payment for his services. The reason he is exempt (according to the Rabanan who argue with Rebbi Meir) when he makes the animal a Tereifah is that the damage is considered damage caused by an Ones, rather than by a Peshi'ah, since it is unusual for an expert to ruin the Shechitah (see RASHI DH Uman Patur). In order to exempt himself from payment, every Shomer Chinam is required to prove that he was not Poshe'a, negligent, when he watched the object, either by making an oath or by bringing testimony of witnesses. (Similarly, if a Shomer Sachar seeks to exempt himself from payment by claiming that the object deposited with him was damaged b'Ones, he must either make an oath or bring witnesses to prove that it was damaged b'Ones.) Since the butcher, who is a Shomer, wanted to exempt himself by claiming that the animal was killed b'Ones and not through Peshi'ah, Rebbi Yochanan required that he prove that there indeed was an Ones by making an oath or by bringing testimony that he was an expert.
This principle -- that a Shomer is exempt only after he proves that an Ones occurred by making an oath or by providing testimony -- does not contradict the rule of "ha'Motzi me'Chaveiro Alav ha'Re'ayah," since this was part of the understood agreement of the Shomer when he accepted responsibility for the object of another person.
The question that remains is why the butcher needed to prove, with the testimony of witnesses, that he was an expert, and he could not exempt himself from paying by making an oath that he was not Poshe'a, like any other Shomer Chinam. The RA'AVAD answers this question by citing the Gemara in Bava Metzia (83a). The Gemara there teaches that if the object deposited with the Shomer was damaged in a manner in which there are likely to have been witnesses who can testify whether it was damaged as a result of an Ones or not, the oath of a Shomer does not exempt him. He must bring witnesses to prove that he was not Poshe'a. Similarly, it is usually common knowledge whether the butcher is an expert or not. Since it is possible for him to bring testimony to prove that he is an expert, it does not suffice to make an oath.
(b) The Shach's answer for why the logic of "Rov Metzuyin Etzel Shechitah Mumchin Hen" does not apply here is unclear. According to the PRI MEGADIM, the Shach means that when a Shochet ruins the Shechitah, the Rov is no longer reliable to state that the Shochet is an expert. REBBI AKIVA EIGER (on the Shulchan Aruch) asks that according to this approach, if it is known that a Shochet once made an animal a Tereifah, the Rov should not be reliable any more to establish that he is a capable Shochet!
The BEIS HA'LEVI (2:4:4) answers that "Rov Metzuyin" is no more than an assumption that if one would ask the Shochet (who slaughtered the animal) whether he is a trustworthy, capable Shochet, he would say that he is. It simply shows that he considers himself a good Shochet. (He bases this on the words of the Rambam and the Re'ah in Bedek ha'Bayis.) Hence, that Rov certainly cannot be used to exempt the Shochet from paying since his own testimony about himself cannot exempt him.
If it is true that the butcher must bring proof that he is an expert because of the Halachos of Shomrim, it could be that the Rov is not a sufficient proof because of the principle that "Ein Holchin b'Mamon Achar ha'Rov." Therefore, the butcher must bring testimony of witnesses to prove that he is an expert (in order to exempt himself from liability).
Another possible answer may be derived from the words of the NIMUKEI YOSEF. He explains that when the Gemara says, "If you are a Mumcheh for [slaughtering] chickens," the word "Mumcheh" means an "Uman Mumcheh," an expert professional. "Rov Metzuyin" might prove that the butcher is a regular Mumcheh, but not a particularly expert Mumcheh, and thus a Hedyot -- an amateur -- also falls into the category of a regular Mumcheh. Therefore, it is not sufficient to exempt him from paying unless he proves that he is an Uman Mumcheh.