Reason vs. Imagination
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 not a symbol of reason but of imagination. He describes it as having grown out of the hand of Nature (or some other creator) and says that it "sang laughed prophesied," casting spells and creating miracles. The entire description of the paradise is one that requires readers to use imaginative power, to make connections between what would otherwise be thought of as disparate images. But these ideas and connections are possible in the imagination and in the subconscious. At the end of the poem, paradise is destroyed and its unity is fragmented. A possible interpretation of this is that reasoned discourse or description, in trying to capture the unified, uninhibited experiences of the subconscious, cannot do justice to it. The explanation of it is doomed to be fragmented and partial.

Language
Related to the idea of the tension between reason and imagination is the concept of the limitations of language. Again it seems dangerous and counter to the spirit of "Fable" to try to tease out a single "meaning" about the nature of language in its lines to explain what is being expressed. Paz seems to be pointing to the idea that there is a gap between an experience and the expression of it in language. Or perhaps he is saying that human experience cannot be expressed in certain types of language. He talks about the unity of the "word." It should be mentioned that the concept of the "word" was important for surrealists, who aimed to restore language to its original purity by releasing it from constricting rules so it could do justice to humans' inner vision. In "Fable," the "word" encompasses all things in the universe. It may be thought of as the true expression of truth that is corrupted by an attempt to recount it in "the language that we speak." When we understand the "word" we understand the primordial nature of human existence, but any attempt to explain what this is in ordinary language is bound to fail. Or it may be that for Paz the "word" is all the facts and feelings of the world that are conveyed in poetry but which cannot be expressed in non-imaginative language, for example in the languages of philosophy or politics or science. So then the "word" may be seen as poetic language that reflects the world in its unity, while its fragmentation symbolizes the attempt of discursive language to explain those things that only poetry can convey.

Myth
Myth is centrally important in Paz's poetry and is connected with his ideas about language and the subconscious. In many of his writings, Paz emphasizes the alienation and isolation of twentieth-century humans from each other and the world. Ancient people, he believed, found meaning and cohesion in their lives through the understanding of sacred stories and rituals. Myths communicate the common values and experiences of people across cultures and histories by tapping into and trying to make sense of humans' basic and common experiences. Myths then are a reflection of humans' subconscious longings and visions of themselves and the world. Paz hoped that a return to an understanding of humans' stories, recreated for the modern world by the poet, could reconnect humanity with its lost soul. Early in his life Paz sought through politics to effect change in society and return people to a more harmonious existence, but became disillusioned and gave up hope for the transformation of society through political revolution. Paz felt also that in the modern age people were removed from religious beliefs that traditionally served to connect them to the sacred, to each other, and to the world. In this secularized and fragmented society, people needed a new world image, new mythology, to give meaning to their existence.

In "Fable" myth functions on various levels. Most obviously, the setting of the poem is a mythical time. It presents a creation myth and a myth of a "golden age" where there is unity and harmony among all things. The poem also calls up biblical and ancient Aztec myths. There is, as mentioned earlier, an allusion to the Tree of Knowledge from the Garden of Eden. There is a symbol of the sun, which was the principle of creation and the source of life in Aztec mythology. The image of the word that appears later in the poem calls up ideas from Christian mythology; in the Christian New Testament, the word or "logos" is all that exists at the beginning of time. With the explosion of the word and the introduction of language, the ancient mythical world is shattered. A feeling of dislocation and disharmony enters where before there was unity. So then the poem may be seen as portraying a wondrous world in which myth and the sacred pervade the landscape but which when destroyed give rise to fragmented, isolated modern existence.