Organic Unity is the idea that all parts of a piece of art function together to make a cohesive narrative. This narrative, through the interrelatedness of its parts,  asserts a claim about life as it is lived. A work lacking organic unity is nothing more than a collection of disparate instances that does not warrant analysis or interpretation. 

Students often wonder if artists mean to infuse meaning into the work. Creating something with organic unity demands the establishment of pattern and selective representation which implies meaning. To put it in simpler terms, here is a typical exchange I have with students who are new to literature:

Me: "When you are able to predict what is going to happen in a movie, when you accurately predict who is the villain, or what the mystery is actually about, does it mean you are psychic?"

Student: "No" - grudgingly said. 

Me: "It is because you recognize the pattern or were able to infer meaning which allowed you to determine what was going to happen next." 

With regards to intentionality, I equate the process of creation to that of the chemist mixing a potion. Even if the chemist does not intend to make an explosion, the right mixture of chemicals will cause one to occur, regardless of intent. The same can be said for the mixture of connotations in a work.*

*I do not completely believe in the intentional fallacy nor am I a complete adherent to the Formalist school of thought. Students should be able to consider authorial intent and new interpretation to understand the dynamic nature of their own communication. This gives them impetus to tame their own words.