In the seventeenth century, one of the most popular arguments for the existence of God was that drawn from the universal consent of mankind; but this argument fell out of favor during the eighteenth century, never really to recover. This article charts some of the key stages in its early modern downfall. It highlights a general shift among the argument’s supporters, away from treating the existence of God as an innate principle to treating it instead as the result of discursive reasoning. And, if that could be made to work, all might still have been well. However, the effect of that shift was to open the door to alternative accounts of the psychological origins of theistic belief, ones based on sources like tradition or fear. But these other sources could not be relied upon to track the truth in the way that either innateness or reason might have done, meaning that the truth of the hypothesis could no longer be demonstrated from the mere fact that so many people believed it. Authors discussed include Lord Herbert of Cherbury, Ralph Cudworth, Edward Stillingfleet, John Locke, Pierre Bayle, Matthew Tindal, and David Hume.