From 1751 to 1764, European Jewry was riven by a very public dispute between two of the most revered talmudic scholars of the day: Jacob Emden and Jonathan Eybeschütz. It began when the former accused the latter of being a secret follower of the 17th-century messianic pretender Shabbetai Tsvi—and therefore, a heretic. Shnayer Leiman comments on this and also on the oft-forgotten role of another esteemed rabbi, Jacob Joshua Falk:
Emden’s animosity toward Eybeschütz . . . could easily be explained away on grounds that are not necessarily bound up with an accusation of heresy. . . . In his autobiography, and certainly in his polemical works, Emden often emerges as a misanthropic, tempestuous, cantankerous, chronically ill, and incessantly whining social misfit and rabbinic genius who did not suffer either fools or [other] rabbinic scholars gladly.
Emden, whose father and grandfather had served as chief rabbis of [the triple community of] Altona, Hamburg, and Wandsbek surely felt that he should have been appointed to succeed them. That he had to live in Altona for some fifteen years [while Eybeschütz held this position] was simply more than he could bear.
It is far more difficult to explain away Jacob Joshua Falk’s animosity toward Eybeschütz on grounds other than the accusation of heresy. . . . [D]uring the key early years of the controversy, from 1751 until 1756, the campaign against Eybeschütz was directed primarily by Falk, then serving as chief rabbi of Frankfurt-am-Main; virtually everyone agreed that no other rabbi in the mid-18th century was in a better position to resolve the controversy.
Yet there are reports that Falk was blind. If so, he would not have been able to examine the amulets bearing kabbalistic incantations composed by Eybeschütz, which were the original basis for the accusations. Leiman, in a thorough investigation of the evidence, shows that it is unlikely Falk was blind when the controversy began—and notes, tellingly, that the earliest source stating that he was can be found in a letter written by Eybeschütz’s son.
Read more on Seforim: https://seforimblog.com/2019/11/the-alleged-blindness-of-r-jacob-joshua-falk-during-the-emden-eibeschuetz-controversy/