An intellectually curious and honest person changes his mind over time, certainly on small matters and sometimes on life values and choices. However, absent conclusive proof of a person’s change of heart, we have to assume that he continued his beliefs. Anything else would open the door to outlandish claims of retractions and reversals.
Regarding halakhic matters, we have to follow the rules of the system in order to determine how to act. In two impassioned responsa, R. Shmuel Landau explains the rules while defending the legacy of his famous father, R. Yechezkel Landau, author of the Noda Bi-Yehudah.
R. Yechezkel Landau had ruled leniently regarding a specific kind of fish, placing his position in writing and informing others of his decision. After his passing, a noted rabbi declared that R. Landau had told him that he retracted this lenient ruling. In a responsum (published in Noda Bi-Yehudah, vol. 2 Yoreh De’ah no. 29), R. Shmuel Landau denied his father’s retraction because he would certainly have told others of this change of heart.
Additionally, R. Shmuel Landau argued that once a position becomes established it attains a chazakah, a presumption of correctness. A single witness is insufficient to overturn a chazakah. Therefore, this rabbi should remain silent about what he claims to know because, due to halakhic rules, he will not be heard nor believed. R. Landau continues to argue at length regarding fish.
In the subsequent responsum (no. 30), R. Landau replies to his correspondent’s hurt feelings. He first hurts them more by denying in sharp words the rabbi’s claim. He continues, though, by pointing out that we would not even believe Moshe Rabbenu about his brother Aharon. This is not because we think he is a liar but because we have rules and procedures of halakhic testimony.
R. Shlomo Zalman Braun (She’arim Metzuyanim Ba-Halakhah, vol. 1 Kuntres Seder Toras Ha-Limmud, Toras Ha-Hora’ah Ve-Ha-Minhagim, par. 24 ) supports R. Shmuel Landau’s claim from the Gemara in Shabbos (136b). R. Shravia quotes Rava as saying about a specific case that a woman must leave her new husband because she is obligated to perform yibum. Ravina says that Rava retracted this position. R. Shravia replies sarcastically that with this kind of logic, Ravina could also permit an animal’s forbidden fat. While we often find in the Talmud conflicting reports of a scholar’s view, we cannot take seriously a disputed and unsupported claim that a scholar retracted.
R. Braun also quotes Tosafos (Yevamos 42b sv. stam) that we should not assume that R. Yehuda Ha-Nassi, the editor of the Mishnah, changed his mind within the Mishnah until we find explicit evidence of it.
While we know that people change their minds, accepting specific claims of this without sufficient proof allows for chaos. Both accidental and intentional misrepresentations will proliferate and scholars’ legacies will suffer. Rather, as in all other matters, we have to follow the guidance of halakhah in the process of careful evaluations of claims.