Robert Weisbuch,  from "A Typology of Death, II: Dickinson in White"  (Part 1), in  Emily Dickinson's Poetry (University of Chicago Press, 1975).

Robert Weisbuch offers a reading of "Because I could not stop for Death," placing it beside other instances where Dickinson uses the figure of Death to interrogate her own assumptions abootherut pain, immortality and the writer's imagination. He distinguishes Dickinson from the other great American romantics (Emerson, Hawthorne, Melville), who tend to abandon their early optimism, becoming darker and more realist over time. Unlike these writers, Dickinson incorporates skepticism and doubt into her work all along, through the presence of figures such as the courtly Death of this poem.

In either case, there is no final loss of faith in "Because I could not stop," but Dickinson's imagination receives a dual setback. The imagination is forced to stop for a terrifying thought, which then forces the imagination to admit that this thought constitutes its circumference of certitude.

We are ready now to answer more fully the question of why Dickinson makes us (and herself) confront these poems of dying and the grave. Dickinson's poetry shows her to be as enamored of Emersonian idealism as Emerson himself; but the realist in Dickinson fights off the bardic seer, and the poems we have just considered represent the realist's thrust. Like Emerson, Dickinson can say that "Paradise is of the option" (L 319), but she has a greater concern than Emerson for blocking forces, psychological and natural. She, too, sees thought as a process of constant expansion, but Emerson's circles become Dickinson's circumferences. That term, "circumference," is often overrated and made the key to an understanding of Dickinson. Thus it becomes mysterious. Simply put, "Circumference" may denote an ultimate, totally inclusive vision, but more often it is a name for the boundaries of thought and suggests exclusion as well. Dickinson strives to measure the imagination rather than to claim everything for it, and she wants it to earn its way, by suffering.