Many people in the United States, including the president, view violent events such as school shootings and the Boston Marathon bombings as part of a struggle between good and evil. This has led to a debate about whether that view helps or prevents Americans from understanding why these things happen.
A few days after the marathon bombings, President Barack Obama spoke at an interfaith service in Boston.
"You’ve shown us, Boston, that in the face of evil, Americans will lift up what’s good," Obama said.
He is not the first U.S. president to use the word "evil."
Ronald Reagan used the word to label the Soviet Union. "To ignore the facts of history and the aggressive impulses of an evil empire," Reagan said.
President George W. Bush used the word to describe Saddam Hussein's Iraq, along with Iran and North Korea. "States like these, and their terrorist allies, constitute an axis of evil," Bush said.
During the recent National Prayer Day sponsored by groups from the religious right, devotees gathered on Capitol Hill and prayed to God to vanquish what they see as evil in Washington and the world.
"We can all do things that bring harm, and when you take that on a worldwide level, you have some pretty massive evil that can take place," said Dave Butts, president of Harvest Prayer Ministries
But what about the religious left? Evangelical pastor Jim Wallis
, an anti-war activist during the Vietnam era, criticized the invasion of Iraq. But, he says the September 11, 2001 terrorist attacks on the United States were evil.
"Evil is real. Evil is very real. How we respond to it can help overcome it, or just extend it and make it grow exponentially," Wallis said.
It may be correct to describe horrific violence as evil. But some people worry that it prevents Americans from having a serious conversation about the causes of terrorism and gun violence.
"For me, evil is what I call a 'black hole' concept," said Phillip Cole
, a professor of applied philosophy at the University of South Wales and author of "The Myth of Evil."
"It kind of blocks our understanding. It prevents us from going any farther. It brings the conversation to a halt," Cole said.
Some scholars say that evil as a category can be useful. They say it can help the human mind know whether to respond to something it does not like with moral outrage or ordinary displeasure.
But Cole says when people attribute evil to an event, they mythologize it and turn it into a Hollywood-like epic struggle.
And that, he adds, can make perceived opponents appear to be monsters.
"Therefore, it's enormously dangerous to identify people as evil, because it opens the door to doing terrible things. And very innocent people have been harmed by that," Cole said.
Cole says even in the Holocaust, the real horror was that it was carried out by ordinary people.
For many Americans, the more that becomes known about the two brothers accused of carrying out the Boston bombings, the more their motives seem to defy categorizing.
President Obama also referred to evil in a 2009 speech when he accepted the Nobel Peace Prize in Oslo, Norway.
"The general theme of the Nobel speech says that this is a dangerous world, where real evil exists out there," Obama said.
He later appeared on the television program PBS Newshou
r to explain his remarks
. Critics said his defense of America's military response to terrorism in the Nobel lecture was the same reasoning his predecessor used to justify the war in Iraq.