In a very important sense, any attempt to explicate the "themes" of "Fable" does a disservice to the poem, because it speaks to readers on a subconscious rather than a conscious level. It seems to try to tell readers about a truth that cannot be explained in intellectual, reasoned terms but which are meaningful and representative of the human experience nonetheless.
One way to see the poem is as a visual representation of the subconscious mind unbounded by the fetters of rational thought. In the harmonious age that is described, there are free associations of images and ideas. Connections are made effortlessly and the fantastic is commonplace. Paz uses and overturns the biblical symbol of the Tree of Knowledge in the Garden of Eden, for in his dreamlike Eden the tree is.....