The speaker's despair mirrors Hardy's own sense of fatigue with the world and his dwindling hope for humanity's future. Distanced from those who have "sought their household fires," the speaker witnesses a landscape filled with death and an ever-increasing "growing gloom." Hardy mourned the decline of agricultural society and saw little to celebrate in England's rapid industrialization, which eroded rural traditions and customs. The speaker's link to the past is severed, leaving him unable to find significance in the present. The new century, symbolized by the thrush's song, offers little promise of meaning. The bird is described as "frail, gaunt, and small," and its "carolings," though joyful and "fullhearted," are an evensong nearing its end. Any potential meaning that a new beginning might hold is missing, both in the landscape and within the speaker's heart.

In Hardy's poem, nature is far from a serene paradise where flowers flourish and animals frolic under the sun. Instead, it is dictated by the relentless cycle of life and death, showing little regard for human needs or desires. In "The Darkling Thrush," nature is devoid of any promise of renewal: “The ancient pulse of germ and birth, / Was shrunken hard and dry.” While Romantic poets like William Wordsworth often depicted nature as awe-inspiring and meaningful, Hardy’s speaker finds no such inspiration in the natural world. Despite pondering the essence of life, he discovers no vitality in nature. Even the thrush, which traditionally symbolizes hope, is described as "aged" and singing its final song. By portraying the barren landscape as a reflection of the speaker's internal state, Hardy offers a bleak commentary on the potential of human nature.

Hardy’s poem employs a traditional meter and rhyme scheme, which acts as a structured framework for the chaotic imagery he portrays. Other structural elements also create coherence that stands in stark contrast to the poem’s themes. For example, the speaker's stance, as he leans "upon a coppice gate," reflects the "Century's corpse outleant." By juxtaposing the disarray of a decaying world with the poem's orderly presentation, Hardy emphasizes his unique role as a poet bridging Victorian England and the modern era.

The primary theme of “The Darkling Thrush” is the despair of the modern temperament. Hardy describes in lyrical, descriptive detail the dying of the old world, but he cannot positively replace the dying with the new. Something is over, all is changed, civilization has decayed, and he does not know what will replace it. In “The Darkling Thrush,” Hardy poses one of the central questions of the modern age and reveals himself as a significant voice of the early twentieth century.

Hardy the modern poet is an isolated man. He has lost his connection with those nineteenth century people who are inside by their household fires. They are connected with one another, and with the natural cycle of death and rebirth, but Hardy, the twentieth century persona, is alone in the cold, surrounded by images of death. He may yearn for that simpler, truer world, and he may seek to recapture something that is lost by using the form of folk themes, but that old century is dead, and the outlook for the new century is bleak indeed.

Hardy saw traditional agricultural society decaying, the earth destroyed by industrialization, and in “The Darkling Thrush” he clearly reveals that he cannot believe in a note of hope. He finds “so little cause for carolings” that he cannot picture the new century or describe it for the reader. Hardy is “unaware” of any hope for the future.

With his tale of the “darkling thrush,” a thrush of evening rather than morning, Hardy rejects the Romantic themes of the nineteenth century. While the song of the thrush is the force that crystallizes his fervorless spirit, Hardy’s thrush is aged, “frail, gaunt and small,” not symbolizing new life but belonging to that dying old century. Even after hearing the thrush’s “full-hearted evensong/ Of joy illimited,” Hardy’s depression is lifted only as far as a state of puzzlement. He comes into the new century unable to believe that even the thrush, that representative of nature, can have a reason to hope.