There has been an idea tossed around (nothing scientific about it, I think) that Earth has been isolated from the rest of the universal community because of its tendency to violence. A friend told me that there have been some good science fiction novels on this topic. She could not name any because it has been so long since she read any.
Does anyone know of a good scifi novel with such a theme? I'd like to read a few and see what good authors make of it. Thanks.