One possible clue to the many ambiguities and levels of meaning in The Man Who Was Thursday is in the novel’s subtitle, A Nightmare, which implies that after debating poetry and anarchy with his friend, Lucian Gregory, Gabriel Syme falls into a reverie in which symbolic events occur and then, the adventure completed, returns to reality. Once this dream structure is accepted, the apparently illogical and progressively symbolic narrative creates no insurmountable difficulties. Nevertheless, it is unlikely that any two readers will arrive at precisely the same interpretation of the meaning behind Syme’s adventures and his encounter with the enigmatic Sunday.

G. K. Chesterton states in his Autobiography that The Man Who Was Thursday was the product of his intellectually and spiritually unsettled youth: “The whole story is a nightmare of things, not as they are, but as they seemed to the young half-pessimist of the 1890’s.” Initially, the major targets of the satire are the negative philosophies that seemed to him to dominate the intellectual atmosphere of the late Victorian period. As Chesterton suggested in his poetic dedication to E. C. Bentley, “Science announced nonentity and art admired decay.”

Each of the anarchists embodies one possible perversion of intellect: Gogol (Tuesday) is the stereotypical gruff, bearded anarchist; Professor de Worms (Friday) is the perverted scholarly intelligence; Dr. Bull (Saturday) represents cold, scientific rationalism, whereas Marquis de St. Eustache (Wednesday) represents decadent aristocracy and death worship; and the Secretary (Monday) embodies political fanaticism and power madness. This political satire, however, changes into something quite different as each of the supposed anarchists is, in turn, exposed as an upholder of the moral order. “I thought it would be fun,” Chesterton commented in an interview, “to make the tearing away of menacing masks reveal benevolence.”

Syme prefers the old world of clearly defined good and evil. However disruptive evil may be, it is preferable to moral and spiritual ambiguity. As he runs from a mob that he believes to be in the service of Sunday (they turn out to be good citizens who believe him to be an anarchist), Syme speculates on his new view of reality: Was not everything, after all, like this bewildering woodland, this dance of dark and light? Everything only a glimpse, the glimpse always unforeseen, and always forgotten. . . . He had found the thing which the modern people call Impressionism, which is another name for that final skepticism which can find no floor to the universe.

Thus, Syme’s nightmare turns from a crusade against tangible evil to a search for reality itself, and that reality—or the absence of it—seems to be embodied in Sunday.

Following a wildly comic chase after Sunday, the search for reality ends in the fantastic, symbolic final scene of the book, where Sunday reveals his identity, only to leave the meaning of the novel more ambiguous than ever. With all the detectives dressed in elaborate costumes that suggest their days in Genesis, Sunday identifies himself. “I am the Sabbath. I am the peace of God.” The detectives challenge him to explain and justify his behavior, but the skepticism of the believers is submerged by the negations of the true denier, Lucian Gregory, who presents himself as the authentic anarchist: “I am the destroyer. I would destroy the world if I could.”

Gregory issues two challenges that bring the book to its ideological climax. He demands that the five detectives—representatives of human moral order—justify themselves in the light of the fact that they have never suffered. Syme, speaking for Chesterton and humanity, denies the anarchist’s charge: “We have been broken upon...