In this chapter I analyse early socialist passions for religion to show how it was the cornerstone in their hopes that a socialist “new world” would not remain merely a “dream world”. I ask why socialists argued with increasing fervour between the early 1830s and 1848 that social reform had to be rooted in spiritual as well as moral values. Two of the largest groups, the Icarians and the Fourierists, moved from a rational deism to Christianity. Both were driven by the need to defend themselves from accusations of immorality levelled against Fourier and the Saint-Simonians because of their rejection of monogamous marriage. The Fourierists, strongly influenced by their dominant female members, transformed Fourier's deity into a Christian God. Cabet, under pressure of “moral outrage” from his critics, did likewise and found that this corresponded to the experiences of the Icarians in their artisan organizations. In rejecting conventional Catholicism when she joined the Saint-Simonians aged 26 in 1831, Jeanne Deroin acknowledged merely that the regular systems of the universe indicated the presence of an intelligent spiritual force: “Proclaiming the law of progress, is acknowledging that the world has a purpose”. A generation later in the Second Republic she described herself as a Christian socialist. She had begun to refer to a God with a capital “D”, usually when she was claiming that woman should be recognized as man's equal because she was more in touch with God's laws than man.