An item used for idolatry (such as if a person bowed down to an animal) - one Baraisa taught that whether it was his own item or another's item, it is prohibited. Another Baraisa taught that if it was his, it is prohibited, but if it was another's, it is permitted.

They wanted to suggest that the first Baraisa is R. Meir and R. Yudah and the second Baraisa is R. Yosa and R. Shimon.

(R. Yosa citing R. Ila): The (first) Baraisa follows all opinions - just as you say there that concerning a living creature, unlike an inanimate object, even though it does not become prohibited for regular use, it does become prohibited for use as a sacrifice; similarly, something that does not belong to him, even though it does not become prohibited for regular use, it does become prohibited for use as a sacrifice.

(R. Shimon ben Lakish): (When the Mishnah taught that if one causes his vine to spread over his neighbor's produce, he prohibits it and he is responsible for it) it is a penalty imposed by R. Meir (even though this person merely 'caused' the damage) and one should actually rule this way. This is learned from the Mishnah's wording - 'caused his vine to spread' - did he actually make it grow? Rather, when it grew, it was with his intent (so it's as if he actually made it grow).

A person once showed a Selah coin to R. Elazar (to approve that it is usable, so that the questioner could accept it as payment from someone). R. Elazar approved it and it was then discovered that it was unfit for use. The case came before R. Shimon ben Lakish who penalised R. Elazar for causing financial loss to the person, based on the following Baraisa...

'One who shows a Dinar coin to a money changer (to give his approval) and it is discovered to be unfit, the money changer is liable', because he was paid for his work (and he should have been more careful).

Question: But was R. Elazar a paid worker?! (He didn't charge for his advice!)

Answer (R. Yaakov bar Acha citing R. Avuna): The reason that a money changer is liable isn't because he is paid; rather, since he is holding the money, it's as if he's a paid worker (and must pay for the damage he caused).

(R. Yosi bei R. Bun): No, Reish Lakish obligated him since R. Elazar himself said that (not just R. Meir, but even) the Rabbanan penalize (for damage that was merely caused) but R. Shimon ben Lakish's opinion is that the penalty is only according to R. Meir (and the Halacha is like the Rabbanan)...

Such a case occurred and R. Shimon ben Lakish asked R. Elazar, "That case of the money changer - whose opinion does it follow?'' R. Elazar replied that it follows the Rabbanan. Reish Lakish told him that if that's his opinion, he must therefore pay the penalty.

(R. Yochanan): (The Mishnah taught that one who causes his vine to spread over his neighbor's produce, he prohibits it and he is responsible for it. R. Yosi and R. Shimon said that a person cannot prohibit that which is not his.) All agree that the grapes are prohibited (as he is prohibiting his own item).

Question (R. Elazar to R. Yochanan): Could it be that the crops of the one who prohibited do not become prohibited and those of the one who did not, do become prohibited?

Over what are they disagreeing? Over one who spreads his vine over another person's produce; but if one spreads another person's vine over his produce, all agree that the crops of the one who prohibits become prohibited.

Question: What would be the law if one spread another person's vine over that person's produce?

Answer: Our Mishnah taught - R. Yosi said that it once happened that a person planted seeds in his vineyard in Shevi'is and R. Akiva ruled that a person cannot prohibit that which is not his. R. Yosi used this case to question the Tana Kama, who must therefore hold that one could prohibit that which is not his.