Niddah 17b

נדה י״ז ע״ב

Learn Niddah 17b step by step: Aramaic beside English, every question, answer and proof colour-coded.

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Topic

Blood found in the פרוזדור: ספק or ודאי, and אביי's two approaches (worry vs. חזקה)

Overview

The amud opens with the last words of the earlier topic: a כלי חרס makes everything in its airspace טמא, even if it is full of mustard seeds. Then a new משנה pictures a woman's body as a house with a חדר, a פרוזדור and an עלייה. Blood from the חדר is טמא, blood from the עלייה is טהור, and blood found in the פרוזדור is טמא because we presume it came from the מקור. In the גמרא, students describe the layout and say there is a לול, an opening, between the עלייה and the פרוזדור. רב הונא then explains that blood found from the לול inward is ודאי טמא, and blood from the לול outward is ספקו טמא. אביי objects that a woman's change in posture could move blood in either direction. So he says we must choose one approach: follow the worry, and both places are a ספק, or follow the חזקה, and inside is ודאי טמא while outside is ודאי טהור. Finally, the גמרא matches these two options to an argument between רבי חייא and רב קטינא about whether blood in the פרוזדור is definitely impure. The discussion continues on the next amud.

Opening lines

The steps (12)

1. ConclusionClosing line of the previous discussion: even a vessel full of mustard seeds
2. StatementThe משנה's parable: a woman's body as a house
3. StatementWhich blood is impure, which is pure, and what about the corridor
4. StatementTwo students explain the layout of the 'house'
5. StatementThe students' rule: inside the opening is doubtful-impure, outside is doubtful-pure
6. ChallengeThe son asks: how can it be a doubt if the משנה calls it a presumption?
7. Resolutionרב הונא clarifies: inside is definitely impure, outside is doubtful-impure
8. Challengeאביי asks: if outside blood might be from the חדר, inside blood might be from the עלייה
9. Resolutionאביי's consistent rule: either both are doubtful, or both are definite
10. Statementרבי חייא and רב קטינא argue about blood in the corridor
11. Proofאביי's worry option supports רב קטינא
12. Proofאביי's presumption option supports רבי חייא