Greater in Wisdom and Age — Eruvin 57a
תוספות עירובין דף נז/א
ואור"ת דהלכה כרב הונא דאמר קרפף לזו וקרפף לזו דגדול היה בחכמה ובמנין מחייא בר רב דזוטר מיניה טובא כדמוכח בסוף פרק יש בערכין (דף טז) שהיה רב הונא מוכיחו
Rabbeinu Tam rules in accordance with Rav Huna, because he was greater in wisdom and age than Chiya bar Rav. This principle, laid down in Avodah Zarah 7a, is similar to the principle that a second Beis Din cannot nullify the prior enactment of another Beis Din unless it is greater than the first one in wisdom and in numbers (Eduyos 1:5; see Ra'avad ad loc. for the age factor).
Some parameters of this principle from Yad Malachi:
- This principle only applies if it is clear that the first Beis Din would not have consented. However, if circumstances have changed to the extent that it is clear that the first Beis Din would have consented to rule differently, the second Beis Din may nullify the first one's ruling (§65).
- This principle only applies to a nullification of the prior enactment. A second Beis Din may, however, add to the first Beis Din's enactment (§66). [Elsewhere, however, Yad Malachi seems to contradict himself (Klalei HaDinim, Aleph §73).]
- A second Beis Din can nullify the first Beis Din's enactment temporarily (הוראת שעה), at times and in places where special exigencies exist (§67).
- Although a second rabbi cannot permit that which another rabbi previously forbade, if the second rabbi is greater in wisdom and age than the first rabbi he may reverse the first rabbi's ruling (Klalei HaDinim, Ches §232).
Igros Moshe, Yoreh Deah 1:127 cites Chasam Sofer, Yoreh Deah §13, who maintains that a rabbi in his city has the same status as a Beis Din, and that therefore another rabbi cannot nullify the first rabbi's enactments unless he is greater in wisdom and age than the first rabbi. Igros Moshe clarifies that this is only in the case of enactments. However, if the first rabbi had only consented to the congregation's enactments, or had only issued advice, then the second rabbi may nullify the first rabbi's ruling even if he is not greater than him in wisdom and age.