Would you consider The Alchemist by Ben Jonson an allegory ?

Allegory is the representation of abstract ideas or principles by charaacters or events in a story. Using this definition, then, The Alchemist is, indeed, allegorical, must as the story The Life of Pi is.

Santiago is an allegorical representation, one might say, of a dreamer, of someone who has longed for a purposeful and meaningful life. The entire story is rich in symbolism all about living the unfullfilled and fulfilled life.