I think that even if Steinbeck had not been aware of Poetics, it was learned in some manner. What Aristotle put together was not something he made up, but rather what he observed and kindly put down in an essay as to what he found to be the "recipe for success" or at the least, the traditional and established norm, as well as discussing the roots of literature form. Much of the nature of Aristotle’s essay can be absorbed through reading as well as studying literature and writing, although most of this, I’m sure, has been based on Aristotle’s input anyway. Even everyday conversation gives us a feel for storytelling.
But I am intrigued by the notion of going so far back into these written basics to see what holds true in Steinbeck’s writing. Unfortunately, I’ve gotten in deep, over my head maybe even, and I’ve starting writing it in a Word Document that will be linked here, and it will have to be broken down into sections rather than a rambling piece. Right now I’m concentrating on the building up of Tragedy (vs. Comedy, which started me on this whole thing, the tragi-comic situation Steinbeck created) and there may need to be subheadings or whatever on Plot, Character, etc. as each is valued by Aristotle in Poetics.
In other words, it’s turned into a project. But the easiest way to understand and post about Poetics is exactly what inspired me to do it–having read it, and then seeing it in action as it applies as I read Cannery Row. It is easier, I think, to find the "rule" or "law" or "norm" as Aristotle lays them out and apply them to the novel, than to write of Poetics and seek out examples. Especially since they have been recognized in Cannery Row as becoming familar.