Monism was not just a philosophical outlook, but also an early twentieth-century new religious movement. Founded by the internationally renowned evolutionary theorist Ernst Haeckel, it was supposed to be a “Religion of Science” that repudiated matter-mind dualism in favor of reverence for a divinized Mother Nature. This article traces the genesis of the German Monist League and how it was transplanted to the United States by the publisher, Paul Carus. Although readers of this journal are likely to know about new religions that embrace “pseudoscience,” the surprise is that Monism had followers with significant scientific renown including multiple Nobel Prize-winning scientists, famous philosophers of science, and even a celebrated sociologist. Scholars of secularism or science and religion will want to know about how Haeckel and his followers constructed a hybrid Scientific Faith or Secular Church that this article demonstrates went on to provide the foundation for professionalizing American philosophy.
