In John Keats When I Have Fears That I May Cease to Be, Keats reflects on the fragility of human life when looked through the grander scope of time and eternity. In the first four lines, he makes note of the literary goals that he wants to accomplish, and his own fears that he may die before he gets to achieve any of them. This is a common fear; one that anyone might come to when acknowledging the possibility that the time needed to achieve their hopes, dreams and ambitions may outpace their lifespan.
The next four lines moves beyond his literary pursuits and into a more personal realm. He broods over the possibility that he may never make any substantial connection to another. He compares the beauty of a romantic bond to that of the night sky: vast and directly above him, but ultimately intangible. And as a concept, it can only be intangible, but in the poem he equates intangibility to something that can never be had, in any way, because it transcends his existence as a human being (“And I think that I may never live to trace/Their shadows with the magic hand of chance”).
The last four lines bring everything into perspective: if his lifespan is only so long, and love something that is forever out of his reach, then in his solitude everything else that could be counted as worthwhile fades away into meaninglessness. When put together, the entire poem has a rather bleak overcast; when combined with it’s accepting tone, it counteracts the way the poem pins corporal, worldly things and attachments to the concept of transcendence. If the human life is only so long, then one must do everything they can to be fulfilled in both their personal and professional spheres, and in doing so, they leave their mark, their legacy. But if these things can’t be achieved, then there truly is nothing left—only a quiet solitude. It raises the concern: can a human life truly have any impact, no matter how brief it is? The poem is, simply, the anxiety and despair of an existential crisis put into stanza and prose.