Beauty is momentary in the mind--The fitful tracing of a portal;But in the flesh it is immortal.The body dies; the body's beauty lives.So evenings die, in their green going,A wave, interminably flowing.
Stevens' work is obsessed with the whole conundrum Plato introduced with the Ideal Forms, perfect in their unknowable terrain, versus the actual thing we see in front of us, aging with time, falling apart and eventually dying. The perfection , the beauty of the body we see, is a construct, a phenomenon we subject to our psychological preferences that make the world tolerable, livable. And when the body dies, it remains beautiful, in memory, in the mind that Stevens addressed in the stanza above it. Stevens , a realist, actually, and not a romantic, would suggest that "beauty" and "spirit" are actual concepts by which we arrange our lives, but that such things only have currency as long as there is someone still alive to remember the particular , place, or thing that embodies the previously mentioned qualities.
Stevens believed language, the vehicle with which we construct our complicated notions of permanence and metaphysical certainty, is finally inadequate to the task of capturing the things of the world as they actually are, in themselves, beyond the assumptions of our paradigms and censoring filters. This is what gave his poems their exquisite lyric tension, the pondering of shapes, concepts, places , arranged just so, altering and changing to other versions of "permanent" perfection as the personality changes , however slightly. Our heaven is a malleable place, he considered, eternal and ever lasting , ironically, only as long as there is someone who remembers to hold those thoughts in mind.