The painting is at the Metropolitan Museum, which considers it an allegory of the sense of sight.
They are, after all, carefully selected “types,” and to isolate them runs the risk of seeing the book as an allegory.
This simple fact is an allegory for the fundamental tension of our modern world.
late 14c., from Old French allegorie (12c.), from Latin allegoria, from Greek allegoria "figurative language, description of one thing under the image of another," literally "a speaking about something else," from allos "another, different" (see alias) + agoreuein "speak openly, speak in the assembly," from agora "assembly" (see agora).
A story that has a deeper or more general meaning in addition to its surface meaning. Allegories are composed of several symbols or metaphors. For example, in The Pilgrim's Progress, by John Bunyan, the character named Christian struggles to escape from a bog or swamp. The story of his difficulty is a symbol of the difficulty of leading a good life in the “bog” of this world. The “bog” is a metaphor or symbol of life's hardships and distractions. Similarly, when Christian loses a heavy pack that he has been carrying on his back, this symbolizes his freedom from the weight of sin that he has been carrying.
used only in Gal. 4:24, where the apostle refers to the history of Isaac the free-born, and Ishmael the slave-born, and makes use of it allegorically. Every parable is an allegory. Nathan (2 Sam. 12:1-4) addresses David in an allegorical narrative. In the eightieth Psalm there is a beautiful allegory: "Thou broughtest a vine out of Egypt," etc. In Eccl. 12:2-6, there is a striking allegorical description of old age.