The interplay between character and external world is something that realist writers always dealt with conscientiously, and it started to drop out with minimalism. Hemingway dropped it out, too, but even in his stories there tends to be a volley going on between the environment and the character. Carver won’t say what the volley is. None of us will.
I guess you might say that minimalism resides in certain omissions, in trusting, à la Beckett, that if you give the sparest sort of context—two people in a trash can, a road at night—it will be like a dreamscape for people’s projections.
This is very well said, and something I've been wondering about for quite awhile. What makes literary characters seem real to us? What forms the boundaries around character? What delineates it; what processes build it up? I've always thought the "volley" was an important component, and that squares with my being somewhat averse to minimalism. But Beattie's right; minimalists like Beckett (whom I love) trust the reader to supply the "dreamscape." To put it another way, the characters' interior depictions are strong and suggestive enough to inspire that dreamscape.
So who's to say which is a more realistic depiction of character or "the world"? We don't come across people in trash cans calmly discussing life every day, but for many readers and playgoers, that psychological reality is fully recognizable. Perhaps it's more so, because they're creating their own context to a larger degree.
Jess Row is getting at this same issue in his recent Boston Review piece. His point, well worth remembering, is that our sense of "realism" is culturally determined. In part, anyway. (There's quite a dust-up going on in the comments to this article. By God, people do care about literature.)