Recurrence and cyclical history
Scholars and critics have noted the theme of cyclic history or recurrence in Miller's works, epitomized in A Canticle for Leibowitz. David Seed, in discussing the treatment of nuclear holocaust in science fiction in his book American Science Fiction and the Cold War: Literature and Film (1992), states, "it was left to Walter M. Miller's A Canticle for Leibowitz to show recurrence taking place in a narrative spanning centuries".[15] David N. Samuelson, whose 1969 doctoral dissertation is considered the "best overall discussion" of the book, calls the "cyclical theme of technological progress and regress ... the foundation-stone on which A Canticle for Leibowitz is built".[3][6]
The story's circular structure – and the cyclical history it presents – support a number of thematic and structural elements which unify its three sections. Although the novel's events take place in a fictional future, the three parts allegorically represent crucial phases of Western history. The first section, "Fiat Homo", depicts a Church preserving civilization, a counterpart to the "Age of Faith" after the Fall of Rome. The action of the second part, "Fiat Lux", focuses on a renaissance of "secular learning", echoing the "divergences of Church and State and of science and faith". "Fiat Voluntas Tua", the final part, is the analog of contemporary civilization, with its "technological marvels, its obsessions with material, worldly power, and its accelerating neglect of faith and the spirit".[16]
In her analysis of Miller's fiction, Rose Secrest connects this theme directly to one of Miller's earlier short fiction works, quoting a passage from "The Ties that Bind", published in the May 1954 edition of If magazine: "All societies go through three phases.... First there is the struggle to integrate in a hostile environment. Then, after integration, comes an explosive expansion of the culture-conquest.... Then a withering of the mother culture, and the rebellious rise of young cultures".[17]
Church versus state
The third part, "Fiat Voluntas Tua", includes a debate between future Church and state stances on abortion and euthanasia, a thematic issue representative of the larger conflict between Church and state.[18] Literary critic Edward Ducharme claimed that "Miller's narrative continually returns to the conflicts between the scientist's search for truth and the state's power".[19]
