The Rule Against Learning From General Statements

The foundational principle treated across these entries is that general statements in halachic literature cannot be used to derive rulings in new cases, and the Sdei Chemed (Maarechet Alef 44) opens the analysis by citing the Atzamot Yosef's distinction regarding Kiddushin: where a Tanna Kamma said "kol" and a later Tanna said "af," we do not apply the rule of ein lomdin min ha-klalos, since the language itself signals that the ruling is precise and intended — and the Sdei Chemed notes that the Nechmad LaMar'eh wrestles with this distinction at length.

On the closely related question of whether one may derive halachic rulings from Midrash or Aggadah, the Sdei Chemed (Maarechet Alef 95) marshals a range of later authorities: he shows from the Tosefot Yom Tov (Pirkei Avot 5) that even where no contradiction from the Talmud is found, we still do not learn from such sources; the Shevut Yaakov (vol. 2, §149) independently concurs; and the Chavot Yair (§224), cited via the Be'er Yaakov, similarly holds this position — though the Shevut Yaakov elsewhere (vol. 2, §178) qualifies that the rule applies specifically when the Midrash runs against the sugya or against reason, while the Pnei Yehoshua in Mayim Chayyim (§128) and in his Chiddushei ha-Shas takes the view that where the Midrash does not contradict the Talmud, we do follow it.

Extending the principle into the domain of rabbinic enactments, the Sdei Chemed (Maarechet Alef 386) records a dispute about whether one may derive a new rabbinic ruling from an existing rabbinic ruling: the Maharadakh limits the prohibition to cases where applying the derivation would uproot a Torah-level law — his example being Rabbenu Tam's takkanah overriding the husband's Biblical right of inheritance — whereas the plain reading of the Rosh in his responsa (Klal 44) holds that ein lomdin applies even where no uprooting of Torah law is involved, on the principle of "do not add to it," a position the Shut Ramatz (Orach Chayyim §12, §3) likewise adopts.