Along with the descriptions of the twenty-eight incarnations that make up the largest section of “Book I: What the Caliph Partly Learned”and the poems “The Phases of the Moon” and “All Souls’ Night,” which frame the main text, “Dove or Swan” is one of the few sections of A Vision that did not undergo a radical revision when Yeats rewrote his philosophical treatise. Indeed, Yeats goes out of his way in “A Packet for Ezra Pound” to call attention to these unchanged sections:

If we, for the moment, take this admission at face value, Yeats is essentially stating these two core texts form the foundation of A Vision(1937). They are the framework of Yeats's system— “the hard symbolic bones under the skin” (AVB24)—upon which he structures his interpretations and understanding of the interchange between the primary and the antithetical.

This foundation, however, is more than metaphor. Because they are constantly grounded in particulars and provide illustrative examples, the description of the twenty-eight incarnations and “Dove or Swan” are the most concrete, comprehensible sections in both editions. As such, they serve a particular function within A Vision B: they are the specific expressions of Yeats's system which follow after and balance against the sections that deal in the abstractions of the more theoretical and philosophical concepts—a structural balance appropriate to his duality-based system.