This poem is a sharp reminder of the mystery that is the future. It is something that many writers have grappled with, trying to sort through views of the future through a lens like Christianity or other religions which contain a divine order, as some see it, or what others perceive as deism, wherein a God created but then stepped back to no longer intervene and watch what unfolds. Some writers, like some of Shakespeare's plays, reference the wheel of fate and its cruel impulsiveness. Dickinson's speaker seems to take a rather athiestic approach, disregarding anything as mystical as prophecy as he or she declares that no one can know the future. For this speaker, not even the hint of the smallest sign will give away that lies a year, a month, a week, a day, an hour, or even a minute ahead.
Life happens unpredictably in this poem. In the second stanza, when the time arrives, what happens simply happens, leaving everyone to scramble to react and adapt. The future careens into the present, "Forestalling Preparation" and leaving man with little choice but to adapt. There is no "substitute" for the future or for the one experiencing. Man does not choose his joys nor his sorrows. And the future, fate or otherwise, remains indifferent to the human condition. The future remains exacting, "His Office but to execute", with no emotion, what fate dictates. There is a stoicism in the poem, an edge that is void of sympathy. In the end, this poem is the ultimate in "open endings" for the poem is left wide for the reader to interpret and to agree or disagree with both Dickinson and the speaker. And at the very literal text level, the poem in itself is wide open, lacking an ending and unknowing what fate awaits it-- to be remembered, to be forgotten among many other poems and pages, to continue, to end.