The first line of the poem sets up the premise of "When I Have Fears." The speaker addresses when he "may cease to be," which suggests that the poem focuses on his worries concerning life and mortality (1). Much of this poem centers on the speaker's regrets of not accomplishing many of his dreams and goals, such as:
And when I feel, fair creature of an hour,
That I shall never look upon thee more (9-10).
Besides looking upon his beloved, the speaker of the poem also wishes to capture all his best ideas in pen from his brain, trace shadowy silhouettes from the clouds, and ponder the beauty of nature. The poem concludes with the speaker's desire to contemplate his regrets and dreams in solitude until the metaphorical end of time.
Keats died of tuberculosis at a very early age. This was a great loss to literature because he was such an obvious genius. During much of his young adulthood he was haunted by the fear of death because he knew he was susceptible to tuberculosis and the disease was usually incurable in his time. He went to Italy hoping that the milder climate would help him cope with his disease, and he is buried in Italy alongside Percy Shelley, another great English poet who died at an early age. Much of Keats' poetry is colored with his reflections on death. Another example is the sonnet which begins with "Bright star, would I were steadfast as thou art!" His greatest poem is "Ode to a Nightingale," and it is full of reflections on human mortality, as is his "Ode to a Grecian Urn." It is sad that such a young man should have to give so much thought to dying, but that was his tragedy. The sonnet which begins with "When I have fears that I may cease to be" quite literally is dealing with his fears of death. He would like to have a full career as a writer, and he would like to marry the girl he loved, but he realized that he only had a tiny role in the vast space and time encompassed in the universe. This sonnet is probably his most sincere and intimate expression of his feelings about his personal tragedy.