This provocative twist on the Bible’s opening line was plastered on the side of 25 Chicago buses this week as part of an advertising crusade by the Indiana Atheist Bus Campaign.

The ads have been cruising between downtown and the city’s North and South sides, including the No. 56 Milwaukee route, since the beginning of the week and will run through June.

"The intent of the campaign is to stimulate discussion of religion and its place in our society," said Charlie Sitzes, a spokesman for the Indiana group who with help from the American Humanist Association has collected more than $10,000 in private donations to buy the ad space in Indiana and Illinois.

The group brought its message to Chicago after a similar campaign in Indiana – to post the slogan "You can be good without God" – was rejected by transit authorities in Bloomington and stalled by officials in South Bend, who didn’t want the ads posted in time for President Barack Obama’s speech at Notre Dame.

Indiana's chapter of the American Civil Liberties Union has sued the Bloomington Public Transportation Corporation on the atheist group's behalf. Bloomington Mayor Mark Kruzan has denounced his own transit system, saying he does not condone government censorship.

"It would appear that where there is more opposition to the message that maybe that would be the place where we needed dialogue more," Sitzes said, maintaining that the slogan is a simple fact.

"All non-believers believe God is a creation of man," he said. "We used to have thousands of gods. Now we’re down to one. We’re getting closer to the true number."

Among the guidelines for determining if an advertisement can run on the CTA is a requirement that the ad be truthful and is "not directed at inciting imminent lawless action."

Last year, eight religious organizations advertised on the city’s mass transit including Muslims, Roman Catholics, Christian Scientists and Seventh Day Adventists. Trinity Christian College is the only religious organization currently advertising on CTA.

Sitzes regrets that the ad campaign– inspired by similar signs in Europe– has encountered so much opposition in his home state. British ads sarcastically consoled passengers with the message: "There’s probably no God. Now stop worrying and enjoy your life."

Last November, the American Humanist Association plastered buses in the nation’s capital with pictures of a man in a Santa suit asking: "Why believe in a god? Just be good for goodness’ sake."

"[Chicago’s] slogan makes the point that religion is a social, man-made creation – like literature, art, politics, and science – and as such, it should be subject to debate like everything else," Sitzes said. He said the perspective of atheists, agnostics and secular humanists are often ignored in the public square

"Atheists, agnostics and secular humanists have a unique perspective on the topic that usually gets ignored in public discussion, and we’d like to make ourselves heard," he said. "The ads aren’t an attack on religious people but an affirmation of a different point of view."

What do you think? Conversation starter or attack ad?