The poem is a part of the lyric genre due to its small size and personal ideas. At the same time, the poem functions as a work of cultural commentary: It has a definable viewpoint on humans and the transitory aspects of them and their culture. The speaker identifies as a member of humanity and uses the plural pronoun “we” to speak for humans as a whole. In keeping with the central theme of the poem—mutability, as the title indicates—the speaker’s identity is unknown. Shelley gives the speaker neither a name nor a gender, and the poem provides no explicit personal information about the speaker. Yet the speaker is not a total mystery. Like Shelley, the speaker believes in the instability of human beings. The speaker is quite confident, too, as they’re comfortable speaking for all humankind.

Another detectable trait about the speaker is their mood. The speaker appears melancholy—that is, it’s like they’re inevitably sad or missing something. The palpable glum generates a melancholy tone from start to finish. The poem begins, “We are as clouds that veil the midnight moon” (Line 1). The comparison relies on a gloomy image.