What is a Short Story Besides Short?

As I have mentioned before I am not much of a short story reader though I am starting to appreciate the form more than I used to. I figured a critical study or history of the form might go a long way to helping me understand it better. I am currently in the midst of Frank O'Connor's book The Lonely Voice: A Study of the Short Story. The book is a series of lectures he delivered at Stanford in 1961 with an introductory essay by the author. The lectures are an attempt to define the short story form by examining the work of some of the great short story writers in order to discover what a short story can and cannot do.   Thus far I am through the author's introduction and the first two lectures. The lectures are interesting, though I feel hindered because I have not read the work of Gogol, whom O'Connor credits as the creator of the form, Turgenev, and Mauspassant, the writers he discusses in the first two lectures. I am undaunted, however, and gleaning what I can.   One of the questions O'Connor raises is what is the difference between a short story and a novel other than length? A good question that has caught me up. What is the difference? I've been thinking about it for a week and I still can't say. Even O'Connor has difficulty and admits it is easier to say what a short story is not rather than what it is.   The short story is a fairly recent literary creation and perhaps it is so difficult to define the form because the form is still evolving. O'Connor finds it easiest to talk about the form in comparison to the novel. After taking several stabs at it (which I'll get to in a second) he tosses up his hands and calls it a case of "you know it when you see it." This is very frustrating for me because I don't think I would be able to tell the difference if given 80 pages and asked if the work in question was a really long short story or a really short novel. Because it is easiest to list, here are some of the things O'Connor says about the short story:

• The short story draws its characters from "submerged populations groups" (Gogol's officials, Turgenev's serfs, Maupassant's prostitutes) and because of this has never had a hero.
• "There is in the short story at its most characteristic something we do not often find in the novel--an intense awareness of human loneliness"
• Time is the greatest asset of the novel, the novelist who flouts this does so at his or her peril. The short story is organic and springs from a single detail, embracing past, present, and future.
• The short story writer differs from the novelist in that the story writer "must be much more of a writer, much more of an artist [...] more of a dramatist."
• The difference between a short story and a novel "is a difference between pure and applied storytelling."

I disagree with some of his assessments, perhaps because over 40 years have passed and both the short story and the novel have changed. And however unsatisfying his ideas are to me at this point, they still provide a whisper of a framework from which to explore for myself what, exactly, is a short story.