That's what I was asking Le Guin (or, rather, myself) as I read the first half of this book. You have this guy, George, who is ordinary -- literally median
, in fact -- except that when he dreams, reality changes to match his dreams. It does this by changing the past so that whatever new thing he dreams of has always been that way
so as far as everyone else is concerned nothing has happened. I read a lot of fantasy and science fiction and am willing to make some pretty damn suspensions to disbelief, but this is just over the limit impossible.
It's supposed to be. I'm sure Le Guin could have thought up some more marginally-plausible mechanism by which one individual could unintentionally and uncontrollably alter reality for the entire universe, but then the readers would have spent half the book thinking about how this worked and whether it was internally consistent, and she didn't want that. It's not possible, forget about that part. The point is to create an original arena for raising a number of huge ethical and philosophical questions.
What is evil? What makes us human? What is the relationship between memory and personality? Can one justify doing harm for the greater good? Is it possibly for a human being to really understand what the greater good is? Do we have free will? What are the moral and practical obligations of power? How do we balance conflicting moral dilemmas? Could we ever really communicate with aliens?
The aliens, by the way, seemed to me suspiciously like a joke about how this isn't really science fiction. This is a novel of ideas, and it doesn't matter how many alien invaders, space battles, time shifts, psychic powers, and futuristic machines you toss in.
All that was the part that was interesting to me. As an actual reading experience the book wasn't very enjoyable. The prose was skillful but not pleasurable, and the characters were boring. To a purpose, and I understand why, but still boring. The most interesting was Heather Lelache, and it bothered be how her character was so reduced in later incarnations. Again, I understand why and that Le Guin was raising issues of free will, gender norms, etc, but I think it was heavy-handed. Really a lot of the didactic purpose of the story seemed heavy-handed, and I wish the hard work involved had been me thinking instead of the struggle to persevere in reading it.