Rambam's Introduction to the Mishneh Torah

The reason for recording the opinion of a single perfect man even though he later withdrew that opinion, such as when the Sages stated, “Bet Shammai say such and such whereas Bet Hillel say such and such, and Bet Hillel reconsidered and taught according to the opinion of Bet Shammai” (M. Edut 1:4, 12) is to demonstrate their love for the truth and pursuit of righteousness. For whom these great men - righteous, understanding, completely knowledgeable, and of eminent scholarship [such as Bet Hillel and Bet Shammai] - saw that the opinions of him who argues with them are more correct that their own and that his [the dissenter] deliberations are better, they would change to his viewpoint. All the more so should other people, when seeing the truth in the argument of their opponent, turn to it (and accept it) without being stubborn. This is the meaning of the scriptural phrase, Justice, justice you shall pursue. (Deut 16:20) It is concerning this matter that the Sages stated “Acknowledge the truth” (Avot 5:7) meaning that even if you could save face [lit. save your soul] with sophisticated counter-arguments, if you know that your opponent’s view point is the truth, although your argument may be clearer due to his weakness in expressing himself, or because of your as view point is the truth, although your argument may be clearer due to his weakness in expressing himself, or because of your ability in argumentation, withdraw to his viewpoint and abandon the fight [admit defeat with dignity]. [Translation by Fred Rosner.]