Organic unity is the idea that a thing is made up of interdependent parts. For example, a body is made up of its constituent organs, and a society is made up of its constituent social roles.
Organic unity was propounded by the philosopher Plato as a theory of literature. He explored the idea in such works as The Republic, Phaedrus, and Gorgias. But it was Aristotle, one of Plato's students, who advanced the idea and discussed it more explicitly. In Aristotle's Poetics he likened drama narrative's and action to organic form, presenting it as “a complete whole, with its several incidents so closely connected that the transposal or withdrawal of any one of them will disjoin and dislocate the whole.” Plato is suggesting removing all love interest, wit, conventional expectations, rhetoric or ornament out of a literary criticism and philosophy. Plato's Republic takes the natural principle birds of a feather flock together as a premise for organic form.
In Poetics (c. 335 BCE), Aristotle describes organic unity by explaining how writing relies internally on narration and drama to be cohesive; but without balance between the two sides, the work suffers. The main theme of organic unity relies on a free-spirited style of writing and by following any guidelines or genre-based habits, the true nature of a work becomes stifled and unreliable on an artistic plane.
The concept of organic unity gained popularity through the New Critics movement. Cleanth Brooks played an integral role in modernizing the organic unity principle. In The Well Wrought Urn, Brooks used the poem "The Canonization" by John Donne as an example to relate the importance of a work’s ability to flow and maintain a theme, so that the work gains momentum from beginning to end. Organic unity is the common thread that keeps a theme from becoming broken and disjointed as a work moves forward.