Chapter 14 of my research book about the morality and politics of our time as seen through the subjects of representational art is now available.
What makes a visual allegory?
When Allegory Works
What Have We Done to Angels by Nelson Shanks works as an allegory because the artist took an object visually charged with meaning imbued by centuries of understanding, and used it in a composition such that we can see what he intends. He meant to show the price paid when we ignore the higher state of being, once described as angels, for reasons of expedience. It is not necessary to know or agree with the Christian tradition to grasp the meaning of the dove figure created with the knot of the string.