Themes are the fundamental and often universal ideas explored in a literary work.

The Power of Ambiguity

Most major concepts are ambiguously defined in Herzog: morality, philosophy, psychology, self, religion, faith, death, and marriage, among others. These concepts, like Moses Herzog himself, are all internally torn between contradictory principles and forces. Nothing seems certain; everything has the potential for paradox. For example, Moses discovers the necessity of society, but he only discovers this through solitary meditation. Only after being totally alone can he turn toward the world.

At the end of the novel, Moses claims in a letter to Dr. Edvig that he is more capable of dealing with ambiguities, and that the uncertainty of faith does not prevent it from being a "relief." God, death, and the future will always be unknown, but we can still be optimistic. Death, which pervades the novel, is the ultimate ambiguity, but Moses eventually learns to accept its existence. He thinks about the death of his father and his mother, faces the prospect of his own death, and comes to believe that life is about the beauty that comes in intervals. He chooses to savor such brief moments of happiness, instead of fearing death.

Bellow beautifies death when he likens it to the soil. Moses' mother tries to prove that God created Adam out of the soil by rubbing her finger into her palm until dirt rises up. When his mother begins to die, he says that "she had begun to change into earth." Her story and death echoes the biblical phrase from Genesis, "dust thou art, and unto dust shalt thou return." This phrase can sound depressing, but it can also sound like a reassurance that we are all part of a cycle, and we all, great and small, return to dust eventually.

The Internal Journey of Modern Man

Saul Bellow reacts to the horrors of history in a different way than do some other writers. The Great Depression, World War II, the Cold War, and the Vietnam War caused widespread disillusionment, which was expressed by great artists such as the poet T.S. Eliot, who wrote the masterpiece "The Wasteland." Moses acknowledges the facts of war and death, but he does not become alienated as a result of them. Moses remembers thinking of the Holocaust when he went to Poland and thought of the death that pervaded the place. He makes reference to both T.S. Eliot and the Holocaust, criticizes the leaders of his country for the war in Vietnam, and condemns an "aesthetic" view of history that ignores death and murder.

Even though Bellow fills his novel with references to death, however, he does not ascribe to the view that historical events should make us jaded. As Moses says in a letter, "We musn't forget how quickly the visions of genius become the canned goods of the intellectuals…the commonplaces of the Wasteland outlook, the chap mental stimulants of Alienation…I can't accept this foolish dreariness." Moses does not call Eliot foolish—he considers Eliot a genius. However, he does think that the ideas of a genius can become corrupted and trite in the minds of ordinary people. Bellow believes that modern man can find communion and beauty in midst of the bleakness and isolation of the modern world. Although Moses does feel alienated, and although the bulk of his novel is about his solitary thoughts, in the end, Moses rejects alienation and solitude. He comes to embrace society and to see the importance of sharing his life with others.