We continue our discussion about the religiously deviant Rebbe....
The Rambam neglected to mention the distinction the gemara mentions between a gadol who may learn from him and a koton who may not. Why? In the previous post we presented one answer.
Another answer is based on the Meiri who has a different understanding of the gemara. He says that 'gadol' and 'koton' are refering not to the talmid [that a talmid who is an adult may learn but an impressionable child may not] as Rashi learns but to the Rebbe. The gemara [in Chagiga] means that if the Rebbe is so great that one can only learn from him then it would be permitted, while if he is not so unique one may not learn from him because he might as well learn from another Rebbe who HAS yiras shomayim.
Wow! What a pshat.
The Rambam then rules like the gemara in Moed Katan that doesn't mention this distinction and forbids everyone to learn from such a Rebbe. This understanding reads kaftor vaferach into the Rambam. He says [Talmud Torah 4/1] that EVEN IF THE REBBE IS SO GREAT THAT ALL OF THE JEWISH PEOPLE NEED HIM it is still forbidden to study under his tutelage. He is clearly precluding the understanding of the gemara in Chagiga that one may learn under such a great Rebbe. So he understood the gemara like the Meiri but didn't codify it as halacha.
The Maharal explains that the reason one may not learn from such a Rebbe is because it is forbidden to connect to a רשע. Rashi and the Rach learn that the reason is because one is liable to be influenced by him.
The gemara in Chagiga which permits one to learn from a unique one-of-a-kind-Rebbe [according to the Meiri and Rambam] is following the understanding of the Maharal that the reason is that it is forbidden to connect to a רשע. But for the tremendous opportunity to learn high level Torah that prohibition is suspended. The gemara in Moed Katan that doesn't give any permission to learn from a deviant Rebbe fits well with the understanding of Rashi and the Ra"ch that one might be negatively influenced. If that is the problem then there can be no heter under any circumstances - even if he is a gadol bi-yisrael and there is nobody who is his peer. On the contrary - since he is so great one is MORE likely to learn from him.
The Rambam ruled like the gemara in Moed Katan and gave no permission under any circumstances.
[See the sefer Dibros Ariel on Chagiga סימן מה]