Considering Mary Shelley's Frankenstein, how might one argue that the monster is superior to humans?
The monster is superior to humans, in part, because he learns faster. Just from observing Safie's lessons, he is able to learn to read and write and speak, and he learns more quickly and more thoroughly than she does. Remember, he is less than two years old at that point! Thus, he is intellectually far superior to us.
Further, the creature is physically superior to humans as well. He is shot when he saves a little girl from drowning, and though it pains him, he survives and is not materially affected by his wound. Moreover, when Victor first sees him, he is "hanging among the rocks of the nearly perpendicular ascent" of a mountain, a feat nearly impossible for a human. In addition to the superhuman strength displayed here, he also shows superhuman speed and the ability to withstand temperature extremes that Victor cannot.
I think one could also make the argument that the creature is emotionally superior to humans as well. Aside from being born quite gentle and beneficent, the creature is ultimately willing to take responsibility for his violence, something Victor is never willing or able to do. Victor says that he does not "'find [his past conduct] blameable,'" even though he ruined so many lives, including his own. However, the creature says to Walton, "'My heart was fashioned to be susceptible of love and sympathy; and, when wrenched by misery to vice and hatred, it did not endure the violence of the change without torture, such as you cannot even imagine.'" He not only takes responsibility for the evil he's done, he also explains the terrible emotional toll it's taken on him.