While the German word übermensch might be most precisely translated as "overman," it appears in this play translated as "superman." The concept of the "superman," an ideal human who will redeem the rest of humanity, is drawn from the works of Friedrich Nietzsche. Nietzsche was a German philosopher who first conceived of this idea in 1883, in his book Thus Spoke Zarathustra. Nietzsche's übermensch is morally superior to any human who has ever existed. But rather than subscribing to a specific moral code, the übermensch is notable precisely because he lacks a strict, preconceived morality. That is to say, rather than basing his ideas of right or wrong off of church doctrines or Victorian mores, the übermensch is capable of seeing beyond arbitrary social structures and norms. He is capable of completely logical moral reasoning, unhampered by social pressure as well as by baser instincts. Within Shaw's play, Jack Tanner embodies the spirit of the übermensch. He views every situation according to his own moral instincts, as if entirely unaffected by the norms of his society.
The only problem with the übermensch is that he doesn't actually exist. All normal humans, according to Nietzsche, are to some extent biased by less noble concerns or are limited in their worldview by the norms of the society in which they live. Therefore, it's only through radical self-improvement that we can strive to produce this superman. In Man and Superman, this perfection is achieved through, and manifests as, the "Life Force," an invisible energy that causes people to seek knowledge and reproduce. This is just one possible interpretation of Nietzsche's übermensch, who can be thought of as a metaphorical symbol or a literal, if not-yet-existing, person. In either case, though, the superman represents a future arrival, whether it's the arrival of a state of being or of a savior figure. Nietzsche himself was an avowed atheist, famous for announcing the death of God in modern society. The characters in Man and Superman seem in their own ways to casually accept that God is dead. They discuss politics, ethics, and science with no mention of religious obligation whatsoever. In spite of that, though, the übermensch/superman is an almost theological concept. It can easily be compared to a messiah, for instance.
Nietzsche did have some beliefs that make most modern audiences uncomfortable—some of which have, in fact, been attractive to reactionary segments of the far right over the past century. For instance, the philosopher found ideas about the fundamental equality of people to be absurd, and he believed that strong people would eventually come to dominate weaker ones. These leanings are visible within the idea of the übermensch—a strong, superior human who is superior to everyone else both physically and mentally doesn't quite square with the idea of equality. On the other hand, the Nietzscheans in Man and Superman are socialists, not fascists, and it seems as if Shaw interprets the übermensch differently—as a force capable of making the world better, and perhaps as an ideal towards which all people might aspire—and therefore a way to make people more equal, rather than less.
