Rabi Akiva came from a family of Geirim, people who had escaped their previous non-Jewish life to embrace the Torah. This is in contrast to Rabi Yishmael who was the Kohen Gadol and came from an illustrious family. This background helps explain how these two Chachachim view Matan Torah. Rabi Akiva perceived it as an opportunity for Bnei Yisrael to break loose from the world and embrace a higher spiritual reality. Therefore, he understands the Pasuk (Shemot 20:15), “VeChol HaAm Ro’im Et HaKolot," “And all the people could see the sounds” literally. Similarly, when Bnei Yisrael responded that they would observe the Mitzvot, Rabi Akiva interprets the Pasuk in the same way. Rather than responding affirmatively to the positive Mitzvot and negatively for the negative Mitzvot, they said yes to every kind of Mitzvah. Their exalted level enabled them to see no difference between the two.
Rabi Yishamel, however, was of the opinion that life itself must be filled with holiness. For him, the key element was not that the spiritual world engulfed the physical, but that the physical world as it stands embraced the spiritual. Therefore, he states that in reality at Har Sinai we saw what is usually seen and heard what is normally heard. He also is of the opinion that Bnei Yisrael did differentiate between the positive and negative Mitzvot.
Rashi appears to have incorporated into his commentary contradictory elements within this dispute. On the one hand he cites the opinion of Rabi Akiva that the sights were seen (ad loc. s.v. Ro’im Et HaKolot); yet, on the other hand, he writes that Bnei Yisrael did differentiate between negative and positive Mitzvot (Shemot 20:1 s.v. Leimor). How can we reconcile Rashi’s seemingly contradictory comments?
The Lubavitcher Rebbe explains that the answer to this question must be understood from the lens which Rashi is working with. Rashi’s job throughout Chumash is in order to teach the simplest understanding of the Pesukim. In the case of accepting the Mitzvot, it is more straightforward to assume that Bnei Yisrael distinguished between positive and negative Mitzvot, and therefore he quoted Rabi Yishmael's opinion. Later, however, when the Pasuk literally says that Bnei Yisrael saw the sounds, it is more straightforward to translate as understood, and therefore he quoted Rabi Akiva in that instance. As we read about the receiving of the Torah, we come to understand through these comments of Rashi’s the depth and range of opinions that are present. While Rashi may seem to contradict himself, he is merely explaining the Torah in the most straightforward manner. The breadth and depth of the Torah enables Rashi to quote various, seemingly contradictory opinions throughout the Torah and represents the exact reason why the reception of the Torah is the greatest gift Hashem has given the world.