When a reader attempts analysis of a poem, she must determine what is literal and what is non-literal meaning. One way to do this is to know some background on the poet and his tropes and preferred images, etc. And what is literal and non-literal can shift, depending on context; this shifting definitely is what Wallace Stevens often does, interlacing mind and matter. For instance, there is the juxtaposition of literal and non-literal in these lines:
Their evocations [literal] are the speech of clouds [non-literal].
So speech [literal]of your processionals returns [non-literal]
In the casual evocations [non-literal] of your tread [literal]
Across the stale, mysterious seasons. [non-literal]
Usually, too, metaphor is at the center of most poetic expression. So, to break the code of a poem, the reader can look for the controlling metaphor. In Stevens' poem, "On the Manners of Addressing Clouds," the controlling metaphor is that of clouds of speech and thought as they affect concerns of human experience. Stevens challenges the words of "gloomy grammarians" and philosophers and ponderers who both obfuscate the enlightenment that imagination can bring to understanding: "Their evocations are the speech of clouds."
In this poem, Stevens challenges formal thought and speech that block ideas and knowledge derived from intuition and the imagination. Instead, this "meet resignation" prevents the illumination of ideas and the play of the mind which are essential in the struggle for meaning. Stevens urges the grammarians and philosophers to not be satisfied with the "mute bare splendors of the sun and the moon" because the imagination can lead people to a deeper understand of the dimensions of beliefs, an understanding that Stevens attempts to probe in poem after poem.