Is it permissible for scholars to speak against each other?

Islam has forbidden backbiting and prohibited it, likening its perpetrator to one who eats the flesh of his dead brother. The Prophet, peace and blessings be upon him, defined it as "your mention of your brother with something he dislikes." Scholars must avoid it, as they are most knowledgeable of its ruling, and backbiting them is even more strictly forbidden. Exceptions to backbiting are made when there is a clear benefit, such as clarifying the errors of scholars to avoid imitating them. This falls under the category of "al-Jarh wal-Ta'deel" (discrediting and accrediting narrators) to expose a narrator's illusion or mistake, due to the benefit derived from it.