Eilu V'Eilu by Rabbi Hershel Schachter

 https://www.torahweb.org/torah/2017/parsha/rsch_shoftim.html

The Talmud, as well as later rabbinical literature, is replete with halachic disputes. The halacha has had to decide which opinion should be followed. Should we assume that the rejected view was mistaken and simply incorrect? The Gemara (Eruvin 13b) states regarding the many disputes between Beis Shamai and Beis Hillel that, "eilu v'eilu divrei Elokim Chaim - both opinions are the words of the Living G-d." although in the overwhelming majority of cases we have not accepted the views of Beis Shamai, this does not mean that they were wrong; one who spends time learning the views of Beis Shamai is in fulfillment of the mitzvah of Talmud Torah. Beis Shamai were also basing their opinions on middos she'ha'Torah nidreshes bohein; they were following the principles and the rules of the Torah She'b'al Peh, just that they came to a different conclusion than Beis Hillel. Therefore learning their opinions would also constitute a proper fulfillment of the mitzvah of Talmud Torah. To use the terminology of Rav Soloveitchik, their views also constitute a cheftza shel Torah.