Some themes of the poem "The Second Coming" by William Butler Yeats are apocalypse, disintegration, transition into a new universe or reality, the mystery of the integration of the old world with the new and the replacement of Christianity with a new mystical spiritualism. Yeats emphasizes that the present existence is falling apart, and a new, ominous reality is going to replace it.
The first image in the first stanza of "The Second Coming" is of a falcon spiraling into the air until it can no longer hear the falconer. Then Yeats mentions that "things fall apart; the center cannot hold," and goes on to describe this present world of war, lost innocence, hypocrisy and iniquity. This coincides with the deep study of mysticism Yeats was into at the time. He believed that patterns of history of both personal and historical importance called gyres account for ever-changing phases of existence. According to Yeats, these gyres intersect like cones, with the small point of one cone set within the wide end of another. As one reality widens and disintegrates, it collapses back in onto the point of the next.
The second stanza uses the phrase "the second coming" at the beginning, and then describes a pitiless sphinx-like creature in a desert, suggesting a bizarre mythical world much different that the present one. Yeats then uses various phrases to bring to mind the first coming, the birth of Christ, such as the "rocking cradle" and the town of Bethlehem. The poem then closes with the suggestion that it is not
Christ arriving at this second coming, but a "rough beast" that "slouches towards Bethlehem." In the poem's conclusion Yeats suggests that out of the chaos of this present era, something is arising that is darker and more sinister.