Eruvin 45b

עירובין מ״ה ע״ב

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Topic

Overlapping ארבע אמות zones, and whether חפצי הפקר acquire שביתה according to רבי יוחנן בן נורי (the rain and cistern proofs)

Overview

This amud finishes the משנה about people limited to ארבע אמות whose zones overlap. The משנה then gives a rule for three people in a row, and רבי שמעון compares that case to three courtyards joined by עירובין. The גמרא opens with רבא asking why רבי יוחנן בן נורי gives a sleeping traveler 2000 אמות. Is it because חפצי הפקר acquire שביתה, or only because a sleeper is treated like someone awake? רב יוסף proves the first option from a ברייתא about rain that fell before יום טוב. רב ספרא challenges that proof. אביי answers with a contradiction between a משנה and a ברייתא about public cisterns, and רב יוסף gives a simpler answer from the wording of the rain ברייתא itself. The גמרא then asks why rain that falls on יום טוב did not acquire שביתה in the ocean or in the clouds. It answers with clouds formed before יום טוב, and with the rule that water absorbed in a cloud cannot acquire שביתה. Because of that second answer, the attempt to prove that there are no תחומין above ten טפחים fails.

Opening lines

The steps (26)

1. StatementThe condition for two people sharing their overlapping area
2. StatementThree people in a row with the middle one overlapping both
3. Statementרבי שמעון compares the case to three courtyards
4. Questionרבא asks what רבי יוחנן בן נורי's reasoning is
5. QuestionFirst side: he should argue about utensils too, but a person shows the רבנן's strength
6. QuestionSecond side: ownerless things don't acquire, but a sleeper is like an awake person
7. Proofרב יוסף brings the case of rain that fell before יום טוב
8. ProofThe rain ברייתא fits if ownerless objects acquire residence
9. ProofWithout the ownerless view, the rain ברייתא fits no one
10. RejectionMaybe the rain counts because the townspeople had it in mind
11. ResolutionA city's cistern follows the city, not 2000 אמות from the cistern
12. ChallengeThe משנה and a ברייתא about public cisterns contradict
13. ResolutionThe two cistern sources follow two different opinions
14. Statementאביי reports his exchange with רב ספרא to רב יוסף
15. Rejectionרב יוסף: refute רב ספרא from the ברייתא itself
16. ConclusionTown-owned rain would follow the townspeople's limits
17. StatementQuoting the rain ברייתא: rain that falls on יום טוב
18. ChallengeShouldn't the rain have acquired שביתה in the ocean?
19. ChallengeThe question only works according to רבי אליעזר
20. Resolutionרבי יצחק: the clouds formed before יום טוב
21. ChallengeMaybe these are different clouds
22. ResolutionThe clouds have an identifying sign
23. ResolutionSecond answer: a doubt in a rabbinic law is treated leniently
24. ChallengeWhy doesn't the water get a home in the clouds?
25. ProofProof that there are no תחומין above ten טפחים
26. RejectionRejection: water inside clouds is absorbed