[W]hat I find most terrifying about stories like Adam Lanza’s is not realizing that neither I nor my loved ones can ever be perfectly safe – I already knew that – but rather that I can all too easily imagine what it might be like to surrender to a horrible impulse. I can’t quite imagine my way into the mind of someone who picks off little children with a rifle, but any number of other horrors are mentally accessible. It only requires focusing intently on the normal rages and frustrations that bedevil anybody, and closing off everything else, including the access of other minds.

J.L. Wall adds:

The all-too-easy imagining he refers to is one of the purposes of literature, and the novel in particular—to bring us closer to those we are not, and who are not, but who could just as easily be.