Shiur 18 – The Boundaries of Zman Kriat Shema: Astronomical Time vs. Sociological Time

The Two Baraitot and Their Apparent Contradiction

The Gemara on Berakhot 8b cites two baraitot in the name of R. Shimon bar Yochai:

First baraita: One may recite Kriat Shema twice — once before amud hashachar (fulfilling Arvit) and once after amud hashachar (fulfilling Shacharit).

Second baraita: One may recite Kriat Shema twice — once before hanetz hachama (fulfilling Arvit) and once after hanetz hachama (fulfilling Shacharit).

The baraitot appear to contradict one another: the first holds sof zman Arvit is amud hashachar and zman Shacharit begins then; the second extends Arvit until hanetz and delays Shacharit until hanetz.

Each baraita also contains an internal tension (ha-gufa kashya): the first is titled shtei pe'amim ba-layla yet allows Shacharit after amud hashachar; the second is titled shtei pe'amim ba-yom yet allows Arvit before hanetz. The Gemara resolves both by appeal to social reality — some people are already awake (be-kumekha) after amud hashachar, and some are still asleep (be-shakhbekha) before hanetz.

Tosafot (Berakhot 8b, s.v. le-olam le-leilu)

Tosafot address each baraita independently, comparing both to the Gemara on Daf Tet (misheyakir).

First baraita: When the Gemara says it is still layla until hanetz, this applies only to she'ar mitzvot (based on the Mishnah in Megillah 19b, which rules that mitzvot yom may be performed be-di'avad from amud hashachar). For Kriat Shema, however, amud hashachar ends zman Arvit — because some people have already risen, making it no longer zman shkhiva. Yet Shacharit cannot begin at amud hashachar either; one must wait for misheyakir, when it becomes genuinely be-kumekha for the majority. Thus Tosafot re-read "after amud hashachar" in this baraita as meaning misheyakir.

Second baraita: Before hanetz, it is already yom for she'ar mitzvot, yet Arvit may still be said because some are still asleep (be-shakhbekha). Shacharit cannot yet be said — those still sleeping prevent the time from being classified as be-kumekha. Tosafot note the contradiction with Daf Tet (misheyakir vs. hanetz) and offer two resolutions: either it is a machloket among tanna'im about R. Akiva's view, or, reversing their earlier position, one may in fact recite both Arvit and Shacharit between amud hashachar and hanetz — Arvit grounded in those still sleeping, Shacharit grounded in those already awake.

The conceptual principle of Tosafot: zmanim of Kriat Shema are determined sociologically, not astronomically. The minority suffices to remove zman shkhiva but not to establish zman kima.

The Rif

The Rif rules: halakha accords with Rabban Gamliel, the first baraita, and the second baraita simultaneously. His resolution:

• Arvit le-khatchila: until chatzot (a siyag directed at the gavra, not a redefinition of zman).
• Arvit be-di'avad or be-mezid: until amud hashachar, because the night — zman shkhiva as a cheftza — remains intact. The Sages addressed the person, not the time.
• Arvit be-sha'at ha-dechak (e.g., a shikkor or choleh): until hanetz hachama, because for such a person it is subjectively still be-shakhbekha.
• Shacharit be-di'avad or be-sha'at ha-dechak: from amud hashachar, because the Mishnah in Megillah establishes amud hashachar as the astronomical onset of day (be-kumekha in some sense). Le-khatchila: from misheyakir, when be-kumekha is fully realized.

The Rambam

The Rambam (Hilkhot Kriat Shema) adopts the Rif's ruling identically, adding a categorical formulation: shikkor and choleh are examples of the broader category of ones. One who recited Arvit after amud hashachar as an ones fulfills his obligation; such a person does not recite Hashkiveinu.

The Ba'al ha-Ma'or

The Ba'al ha-Ma'or (R. Zerachiah ha-Levi, Provence) rejects the Rif entirely: the two baraitot are in explicit machloket and it is impossible to rule like both simultaneously (hikhei mazki shetara le-bei trei). He rules in accordance with the second baraita, making sof zman Arvit = hanetz hachama, and the beginning of zman Shacharit = precisely at hanetz. Zman Arvit ends only where zman Shacharit begins — there is no overlap.

The Ramban (Milchamot Hashem)

The Ramban defends the Rif while deploying all the analytical tools of 13th-century scholarship:

• Until amud hashachar: unquestionably night; Arvit may be said even be-mezid be-fishia.
• From amud hashachar: astronomically day for all purposes (yom le-khol davar) — contrary to Tosafot, who maintained it is still night. The Ramban bases this on Megillah.
• Yet Arvit may still be said after amud hashachar for an ones, because the Torah says be-shakhbekha in the singular — making the determination individual. As long as this person was genuinely sleeping, it is his zman shkhiva.
• Arvit cannot be said after hanetz hachama because from that point leykhei anka de-ganei — there is no longer anyone still sleeping. (The Ramban implies that theoretically, if people genuinely slept past hanetz, Arvit could in principle apply — the Rashba limits this, ruling that after hanetz, since it is day by every astronomical measure, the framework of be-shakhbekha can no longer apply even for an ones.)
• The two baraitot are not in machloket: the first addresses a standard case (non-ones), the second a case of ones.

Summary of Positions