Zevachim 96B

ואפילו רבי יוסי ברבי יהודה לא קאמר אלא דעץ, אבל דחרס לא.

And even R' Yosei, son of R' Yehuda, says only that a service vessel may be fashioned of wood, which is a somewhat significant material, but with regard to a service vessel fashioned of earthenware, he holds that this is not valid.

רב יצחק בר יהודה הוה רגיל קמיה דרמי בר חמא, שבקיה ואזל לרב ששת. יומא חד פגע ביה, אמר ליה: אלקפטא נקטן, ריחא אתי לה ליד?! משום דאזלת לך לקמיה דרב ששת, הוית לך כי רב ששת?!

§ The Talmud relates an incident related to the halakha of scouring and rinsing. Rav Yitzḥak bar Yehuda was initially accustomed to study Torah before Rami bar Ḥama. After some time, he left him and went to study before Rav Sheshet. One day Rami bar Ḥama met him and said to him colloquially: Did you assume, as many do, that when the chief of taxes [alkafta] grasped me by the hand, the fragrance of his hand came to my hand? Do you think that because you went away from me in order to study before Rav Sheshet, have you become like Rav Sheshet merely by association?

אמר ליה: לאו משום הכי; מר ⁠– כי בעינא מילתא, פשיט לי מסברא; כי משכחנא מתניתא ⁠– פרכא לה. רב ששת ⁠– כי בעינא מילתא מיניה, פשיט לי ממתניתא; דכי נמי משכחת מתניתא ופרכא ⁠– מתניתא ומתניתא היא.

Rav Yitzḥak bar Yehuda said to him: It is not due to that reason that I went to study before Rav Sheshet, but for another reason. As for you, Master, when I ask with regard to any matter, Master resolves the question for me through reasoning. Consequently, when I find a Mishnah that opposes that reasoning, it refutes Master’s proposed resolution. As for Rav Sheshet, when I ask of him a question concerning any matter, he resolves the question for me by citing a Mishnah. Consequently, when I also find a Mishnah, and that Mishnah refutes the proposed resolution, it is a dispute between one Mishnah and another Mishnah, which does not necessarily refute the Mishnah that he cited.