On the surface at least, More Than Human embodies some common themes of science fiction: the misfit mutants, superior to and alienated from normal human society; the next stage of human evolution viewed as the development of a higher consciousness linking all humanity; the impact on society of psychic powers. Yet, while Sturgeon's speculations on all these matters are in themselves quite interesting and entertaining, the heart of the novel lies elsewhere; all the science fictional apparatus merely provides him with a set of metaphors that express his abiding concern with the themes of alienation and love.

As several critics have pointed out, More Than Human, like many other science fiction stories, is at a deep level a wishfulfillment fantasy of power. The scorned and neglected children possess remarkable powers. Lone, the hapless idiot, can look into a man's eyes and wordlessly order him to commit suicide; Janie, the hated daughter of an unfaithful wife, is a telekineticist; Beanie and Bonnie, black twins with speech impediments, are teleports; Baby, a Mongoloid child, is a computer of limitless power; and Gerry, the bitter runaway from a Dickensian orphanage, combines Lone's powers with a keen and angry intelligence. And their individual powers are only the beginning, for together they comprise a single entity, "Homo Gestalt," the apparent beginning of a new species. Perhaps the most frightening moment of the novel occurs when Gerry finally recognizes the nature of Homo Gestalt and his own function as its controlling will and intelligence. Asked by the psychiatrist who has helped him what he plans to do next, Gerry responds that he wants to have fun, "the kind of fun everybody has . . . kicking someone around, someone small who can't fight back . . . What the hell is morality, anyway?" The stage seems set for a power fantasy of revenge, like Stephen King's Carrie (1974).

The quality of the novel, however, lies in its controlling ethical vision. Gerry—and Homo Gestalt—in fact learn what morality is. The novel's climax is not Gerry's recognition of his powers, nor the acts of cruelty he subsequently commits. Homo Gestalt is not complete with his intellectual maturation; it remains fragmented and alienated against itself, normal human society, and a society of its fellow Gestalt creatures until the incorporation of one final member, Hip Barrows. Hip is another neglected child, but he has no special powers; he is merely the conscience of Homo Gestalt, "the one with the insight called ethics who can change it to the habit called morals." Hip triumphs over Gerry by forcing him to confront the evil he has done and recognize it as evil. And Gerry's shame and renunciation of his past behavior set the stage for the novel's final vision of a transcendent, godlike humanity. But it is essential to realize that this transcendence, for Sturgeon, comes only after individual humans become morally aware and responsible. People cannot become more than human without first becoming fully human.