A lover of both poetry and nature, Coleridge found himself on the side of nature rather than literary tradition when it came to the song of the nightingale. Ever since the story of Philomela’s fate in classical mythology—as she fled from the man who raped her and cut out her tongue, she was transformed into a nightingale—the nightingale’s song has been understood by poets as an expression of grief and melancholy. In Elizabethan times, Sir Philip Sidney and William Shakespeare alluded to the myth, which was also taken up by 17th-century poet John Milton.

In “Il Penseroso,” Milton presents a picture of the melancholy man. The speaker of the poem is in service to “thou goddess, sage and holy, / [...] divinest Melancholy” (Milton, Lines 11-12), and he seeks inspiration from her. The speaker says that he often wanders in the woods in the evenings just to hear the nightingale sing, but unlike Coleridge, writing over 165 years later, this speaker hears a “Most musical, most melancholy!” (Milton, Line 62) sound—this is the line that Coleridge quotes—not the joyful song that the later poet hears. Coleridge takes his stand for nature in the here and now, as experienced by the awakened and receptive senses that drink in its joy, including the joy expressed in the nightingale’s song. Coleridge is somewhat animated by the reversal of poetic tradition that he wants to bring about, and his presentation of his case takes up nearly a quarter of the poem.

Ignoring literary tradition, Coleridge suggests a different origin of the melancholy song:

But some night-wandering man whose heart was pierced

With the remembrance of a grievous wrong,

Or slow distemper, or neglected love,

(And so, poor wretch! filled all things with himself,

And made all gentle sounds tell back the tale

Of his own sorrow) he, and such as he,

First named these notes a melancholy strain (Lines 16-22).

There is an irony in the expression “night-wandering man” (Line 16) because Coleridge in the poem also wanders the night with his friends, but he hears a song that is very different from the one heard by Milton’s melancholy speaker. Coleridge’s point is that the “night-wandering man” was merely projecting onto the nightingale his own sorrow and distress. He was turned inward, engrossed in his negative thoughts, and thus he reconstructed an aspect of nature’s joyousness in the image of his own disappointed, unsuccessful-in-love self. Instead of actually listening to nature, he filled it, as the poet says, “with himself,” (Line 19) and certainly not his best self.

Others poets have followed him, Coleridge says, and he is not surprised by the fact (Line 34). They do not realize that they would have been better off going outside and absorbing the spirit of nature rather than thinking all the time about “building up the rhyme” (Line 24) and becoming famous. (Both these points are likely an allusion to Milton’s presentation of the poet’s goals in his famous 1638 elegy “Lycidas.”) If these poets could learn to be true to their real experience in nature, not to something they have invented in their own mind or that has been passed down to them by others, the only result would be joy, within and without. The poet would then become a co-creator of nature’s beauty, making it even “lovelier” (Line 33) through his verse—just as Coleridge himself aspired to do.

Continuing his argument, Coleridge writes that, regrettably, poetically inclined young men and women, presumably influenced by their reading, are given to indulging their sorrows in love in “ball-rooms and hot theatres” (Line 37)—indoor locations—and they latch on to the “pity-pleading” (Line 39) song of Philomela the nightingale as a kindred spirit. As with the poets, they are not responding to anything in nature that is objectively true; the melancholy song they hear is simply a reflection of the sad emotions that they are allowing to take over their minds. True poetry, says Coleridge, offers a better way.