Rosh (55.9) No one's view - not even Rashi's - is automatically accepted

from Daas Torah - translation copyrighted

Rosh (55.9): You wrote that because of the perfection of the distinguished scholar Rabbi Yaakov ben Shushon no one would think to question his views and reject his explanation. That is not a reason for not disagreeing with an authority. Who is greater than Rashi who illuminated our eyes in the darkness of exile with his commentaries and yet his own descendants Rabbeinu Tam and Ri disagreed with him concerning many issues and rejected his words. That is because it is the Torah of truth and we submit to no man because of his status and authority. And this that you said he was perfected in reasoning or language – it doesn’t matter because Yiftach in his generation is like Shmuel in his (Rosh HaShanna 25b)… Furthermore the Gaonim (Seder Tanaym and Amoraim #25) have said that from Abaye and Rava the halacha follows the more recent authority – not the previous ones…