The Gemara brings Machlokes between the Tanna Didan and Rabbi Yehoshua ben Korcha to which Rashi comments that Rabbi Yehoshua ben Korcha does not agree with the Tanna Didan because he does not hold of the Geziara Shava of Prazi/Prazi because: "He (R Yehoshua Ben Korcha) does not learn the Geziara Shava from his Rebbe and a person does not make his own Geziara Shava which he does not have a mesorah from his Rebbe"
According to Rashi who understands that R Yehoshua ben Korcha is the son of Rabbi Akiva and that Rabbi Akiva is Tana Didan, then Rabbi Akiva is arguing with his son, how can Rabbi Akiva, have a mesorah for this Geziara Shava while his own son did not have this same mesorah?
מגילה ב:
בשלמא רבי יהושע בן קרחה לא אמר כתנא דידן דלית ליה פרזי פרזי
רש״י שם
פרזי פרזי. לא גמיר גזירה שוה מרביה ואין אדם דן גזירה שוה מעצמו אלא אם כן קיבלה מרבו
מגילה ב.
אמר רבה בר בר חנה א"ר יוחנן זו דברי ר"ע סתימתאה דדריש זמן זמנם זמניהם
רש״י שם
זו דברי ר' עקיבא. הכי גמיר רבי יוחנן מרביה דמתני' ר"ע אמרה:
רש״י שבועות ו.
יהושע בנו של ר' עקיבא. הוא יהושע בן קרחה שר' עקיבא קרח היה כדאמרי' בבכורות (דף נח.) חוץ מן הקרח הזה:
Noah Zisquit, Boca Raton, US
halom Noah,
Very good question. I haven't seen a good answer to this question yet.
In any case, it is important to divide the question into two parts.
The first part is the specific question about Rebbi Yehoshua ben Karchah, and according to Rashi who writes in several places that he was the son of Rebbi Akiva. On this I would like to point out the words of Tosfos (Shabbos 150a, Bava Basra 113a, Bechoros 58a) and other Rishonim who do not accept Rashi's opinion. It seems that most of the differing opinions about Rashi are due to many difficulties and problems with his opinion.
In any case, it can be said that perhaps Rebbi Yehoshua did not study with his father, since it is known that his father was not at home for many years (24 years at least), although it is part of the discussion when exactly was Rebbi Yehoshua born, if he is actually Rebbi Akiva's son. But this is a hypothesis and I have no authoritative source for this.
The second part refers to the general question about Gezeirah Shavah which is not derived unless there is a tradition about it. Here, too, there is a lot to expand on regarding what exactly is the requirement that a Talmid should hear from his Rebbi, and what is there for him to derive on his own. But for the very question of how it is possible for one Tana to learn a Gezeirah Shavah that he learned from his rebbi, and the Tana who disagrees with him cannot learn the Gezeirah Shavah from his Bar Plugta who did learn it from previous generations, and especially here that it may even be his father, I would like to refer to the words of Tosfos (Shabbos 97a) who asks the question. He says something interesting. He says that what was known from Har Sinai is that there are a clear number of Gezeiros Shavos in the Torah in general, and when the Tana'im argue about whether or not to learn something from a Gezeirah Shavah, they are actually arguing about whether this specific derivation is included in the general number. In our case, this explanation does not fit so well, since, after all, this is about a Gezeirah Shavah on a word from Esther and not a word from the Torah, so it is a bit difficult to assume that this specific Gezeirah Shavah was included in the number from Har Sinai, especially since there are no other Gezeiros Shavos derived in Megilas Esther, so it is difficult to understand what is the proposed replacement for this Gezeirah Shavah.
Best Regards,
Aharon Steiner