The best way to approach this posthumous novella is to define “solipsism”—solus meaning “alone,” ipse denoting “self,” in Latin. The psychology of solipsism contends that the self can be aware of nothing but its own experiences and states. The philosophy of solipsism argues that, therefore, the only existence of which one can be absolutely sure is the self.
In this remarkably radical story, Mark Twain actually goes beyond the philosophy of solipsism. He does not simply say that nothing but the self can be known by the self. He says that nothing but the self exists. Thus, at the end, Theodor finds himself—and this discovery of self is customary in the Bildungsroman (psychological novel)—but at a staggering price. The self he discovers is only a thought, and the universe with which he was dealing is only his imaginative dream.
In addition to this major argument of the novella, there are several minor themes. Satan was an angel before his fall, but since God figures nowhere in the narrative, Satan rules the world of the story. Satan is immortal and as different from Theodor as an elephant from a small red spider; he is indifferent to the plight of humanity and totally without moral scruples.
The negative summary of human history was achieved before in the Genesis story of the Flood and in William Godwin’s Enquiry Concerning Political Justice and Its Influence on General Virtue and Happiness (1793). Absolutely no Utopian dreams such as those in Plato’s Republic (fourth century B.C.), Thomas More’s Utopia (1516), or Samuel Butler’s Erewhon (1872) are offered here by Twain. Indeed,this savage diatribe has only two objects of praise: animals and laughter.