Resources for Yevamos daf 83
1. The משנה says that if someone puts their grape vine over someone else’s wheat in a way that they grow together, רבי יוסי ורבי שמעון say that the wheat is permissible to eat since one cannot אסור someone else’s food. תוספות in ד"ה אין asks a basic question: if someone throws their treif food in your pot it won’t it become אסור? So why wouldn’t the wheat in our case become אסור as well? He answers that when an איסור requires thought and intention to make it אסור, then you cannot אסור someone else’s stuff. However, when thought is not relevant then you can make someone else’s thing אסור. The case here of כלאים requires thought since if you weren’t happy about the growth then it wouldn’t be אסור. In קובץ הערות in סימן ע"ו אות א׳ וג, רב אלחנן זצ"ל explains in a broader sense that there are two types of actions: ones where man’s input is needed to create the חלות and ones where the action is independent of man’s intention. For example, while שחיטה requires a person’s כח to do the act, the act stands on it’s own and doesn’t need man’s intention to make a חלות. However, קידושין for example is based on man’s intention and the act of giving a ring doesn’t create a קידושין if there was no intention of marriage accompanying it. There are countless נפקא מינהs that he brings. One is our concept of אין אדם אוסר דבר שאינו שלו where the concept only applies where man’s intention is needed to make the איסור (such as here where he needs to be happy about the כלאים growing). Another example is whether תנאי works. תנאי is only relevant to something like קנין or קידושין where your intention matters. By שחיטה for example, if you make a תנאי that it shouldn’t be considered shechted unless something happens, your תנאי is irrelevant since the action happened. Lastly, the concept of אי עביד לא מהני (if you did an action against the תורה it isn’t חל) can only make sense by something where man needs to make the חלות such as by being מקדש חייבי לאווין. However, if someone shechts on שבת the animal is kosher since the act is a reality on it’s own independent of your thoughts.
1a. The תוספות ישנים here as well as the ר"ש on this משנה disagree with the תוספות mentioned above since we find that you can ruin your friend’s פּרה אדומה by making it work even though if you aren’t ניחא ליה with the work it isn’t פּסול. Therefore, they hold that we only say אין אדם אוסר דבר שאינו שלו by כלאים (and ע"ז). כלאים is unique since there is a דיוק in the פּסוק that says it must be yours; otherwise someone else could אסור it. רבי עקיבא איגר in או"ח סימן רנ"ג סעיף ב has a fascinating הערה: if you have fully cooked food on the stove on Shabbos and then you take it off the stove and put it down, you are not allowed to put it back on the stove. However, if you had intention to put it back and never put it down (plus some other conditions) then you could put it back. What if someone else took your pot off the stove and still had it in his hand but had intention not to put it back? Do we say אין אדם אוסר דבר שאינו שלו? He says it should be תלוי in the מחלוקת ראשונים we mentioned. He explains that the יסוד המחלוקת between תוספות and the ר"ש is that according to תוספות, any act which can’t אסור something without accompanying thought cannot forbid your friends item. However, the ר"ש holds that תוספות is only right if the action itself is meaningless without thought. However, if the action is itself a meaningful action but thought can uproot it, then in that case you could אסור your friend’s thing (with the one exception of כלאים). Therefore, by the pot, taking it off the fire and putting it down is an independent action like שחיטה. However, if you are still holding it in your hand, the only issue is your thought to not return it. So תוספות would say you can’t אסור your friend’s pot whereas the תוספות ישנים and the ר"ש would say that taking it off the stove is a meaningful act without thought; it’s just that thought can uproot the action. Therefore, you could אסור your friend’s pot.
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