A Dutch clergyman, Bekker was the most far-reaching opponent of witchcraft in the 17th century. He denied that spirits could influence human affairs or that demonic pacts were possible, and argued that it was better to look for natural explanations than for witches. Labeling him an atheist, the Dutch Reformed Church defrocked and expelled Bekker for refusing to recant his views. He became a frequent target of most writers on the subject, especially for denying the existence of demonic possession.