The recent mass shooting at a movie theater here in Colorado is a classic example of evil. The death of potentially hundreds of people was coldly planned for months. The randomness of the targets suggests that they were but objects in the murderer's mind, with no value as fellow human beings.
Objectification of people, which I've traced as a key enabler of evil, is also at the root of the vast plundering done by people seeking perpetually increasing power for themselves or those they work for. The difference is scale: the theater killer exercised the ultimate power, the power of life and death, over a much smaller number than many leaders of organizations (such as businesses, governments, and religious institutions) have the potential to affect.
Predictably, a lot of attention has been directed toward the issue of accessibility to guns. Guns are relevant only because they are extremely efficient multipliers of power that don't by design ensure that their users are capable, or willing, to exercise a proportional amount of responsibility. Cultural tools, such as education and enforceable laws of behavior need to be in place to fill that gap, and clearly they weren't.
We are left more vulnerable to these kinds of events as cultural tools are disabled, removed, or rendered incapable of being improved or replaced with better ones. Similarly, we are at increasing risk of being harmed when the designs of our tools are left to the whims of people who either can't or won't anticipate and mitigate the tools' potential negative impacts on people and their environments. Without some outside force (such as an all-powerful – and preferably benevolent – deity, for which there is no evidence of existence) to protect us from ourselves, we must rely on each other to instill and exercise responsibility so we can keep the risk of harm to a minimum.
There are some of us who will harm people for reasons that can't be anticipated or offset. They must be deprived of the power to do so, by isolation or other means. To the extent that a society is willing and capable of doing so, it will survive, but it must constantly try to build up its ability to anticipate and mitigate such threats while enabling people to achieve maximum happiness. If we abandon this challenge, we do so at our great peril.