"The Idea of Order at Key West" begins with a lyrical phrase containing a direct comparison between art and nature:
She sang beyond the genius of the sea.
This is one of Stevens's characteristic themes. It is not merely a competition between art and nature, in which art is shown to be superior. Rather, art sits at the summit of nature and imposes order upon it. The water is a "body wholly body." It is art that provides the mind, structure and rigor.
The mind itself, therefore, is at its most rigorous when it is artistic, possessed by the "Blessed rage for order" the poet invokes on the final stanza. This is how art influences the mind, by imbuing both creation and appreciation with order. The poem is remarkable in the way it combines numinous mystery and logical rigor. This combination is expressed in the creative act of the singer, who imposes order on her surroundings and the minds of her hearers at the same time as creating a new world in her song. Stevens says the song is the only world that exists for her: "the one she sang, and, singing, made."
The sea in the poem is depicted as naturally empty and formless. When, in the penultimate stanza, the poet turns away from the sea, he sees the lights from the fishing boats imposing order on the night and the sea as the singer's song did:
The lights in the fishing boats at anchor there,
As the night descended, tilting in the air,
Mastered the night and portioned out the sea,
Fixing emblazoned zones and fiery poles,
Arranging, deepening, enchanting night.
Stevens sees this as the highest role of humanity, using the minds developed and refined by art to impose order on chaos, even if only by shining a light on it. Art shapes the human mind both through original creation on appreciation. Then, through its clarifying effect on our minds, art influences everything else.