The session was titled "The Design of Life," and the TED audience was probably expecting remarks about evolution's role in our history from biologist Richard Dawkins.
Instead, he launched into a full-on appeal for atheists to make public their beliefs and to aggressively fight the incursion of religion into politics and education.
Scientists and intellectuals hold very different beliefs about God from the American public, he says, yet they are cowed by the overall political environment.
Dawkins' scornful tone drew strongly mixed reactions from the audience; some stood and applauded his courage.
Others wondered whether his strident approach could do more harm than good.
Dawkins went on to publish The God Delusion and become perhaps the world's best-known atheist.