This poem opens with the declaration that there is a certain kind of light in early spring (“A Light exists in Spring”), right at the opening of March (“When March is scarcely here”), that isn’t present at any other time of year (“Not present on the Year / At any other period –“). This light cannot be measured scientifically or quantified in anyway (“That Science cannot overtake”), but it can still be observed, felt, and is therefore real (“But Human Nature feels”).
This light, which illuminates all in the observer’s sight, from “the Lawn” to “the furthest Tree / Upon the furthest Slope you know,” has such a powerful effect on the speaker that it feels like direct communication (“It almost speaks to you”). This quality of light is, however, unfortunately ephemeral, and as time passes (“Noons report away”), which it does, even if one does not hear a bell tolling (“Without the Formula of sound”), so too does the light, leaving the observer behind (“It passes and we stay –“).
The passing of this light does not ruin the speaker’s content completely, but it adds a quality of loss to it (“A quality of loss / Affecting our Content”). She compares this to how it would feel, for example, if the sacrament lost its divinity (“As Trade had suddenly encroached / Upon a Sacrament”), because trade, or business, encroaching on the sacrament would strip it of its divinity, as we can imagine, the loss of this light strips this scene of its majestic quality.
“A Light exists in Spring,” although ostensibly one of Dickinson’s nature poems, makes this experience of nature a rather religious one. There are many things that hint to this, but this “Light” is first clearly aligned with the religious when it is described as being something beyond science, something that can be felt by humans but not understood by science, just as the divine is often presented to be.
Science doesn’t just fail to understand this light, but it “cannot overtake” it, as if understanding it would diminish its power; and yet, the light is still fully real and able to be experienced. This light—perhaps a light of belief—stands “On Solitary Fields.” It is not something that comes upon a person when they are busy or surrounded by others, but only in the lonely parts of the natural world, like the solitary experience of gaining belief. There is something communal in the light, too however, just as in religion, as shown by the speaker’s use of the second person, as well as her use of the word “we,” later in the poem.
The light’s presence illuminates the whole of the speaker’s world, from the lawn to the very limits, not only of the speaker’s sight, but of her knowledge, and her reader’s knowledge—“the furthest Slope you know,” not the furthest slope you can see. The diction here, in choosing “know,” thus shows that the light does not just affect the speaker’s external vision, but also her internal vision where her knowledge of the slope lies even without its physical presence, which makes the experience of this light seem very likely to be a religious one.
This light, too, shows a kind of agency—it “waits upon the Lawn,” it “almost speaks to you,” like a kind of divine vision that has a specific person in mind to receive it. The connection between this natural scene and a religious experience is solidified by the final simile of the poem. This light does not remain for the speaker, it is a momentary experience, and the “quality of loss” that follows its absence is compared to trade, mundane and irreligious as it is, encroaching upon “a Sacrament,” something divine, and thereby taking the divine out of the experience.
The absence of this light, then, makes the natural scene again just a natural scene, capable of being measured by science, without the comforting feeling of another presence there with the observer. This experience of the loss of the light, then, makes nature not just something that can show the speaker inspiration and closeness to God, but also something that teaches despair, loss, and loneliness. It shows the speaker and the reader the dangers of losing the divine presence in their lives.