As was true of most intellectual trends in colonial America, deism originated in England and spread to the colonies. To understand deism as it developed in eighteenth century America, one must examine the roots and mature status of deism in England. Deism did not emerge as an entirely new system of thought in seventeenth century England. The disputes, schisms and wars of the Reformation laid a negative foundation for its appearance. The counter-accusations of the clergy of different sects provided ammunition for its anticlerical campaign. The Reformation itself, by its rejection of the ritualism and authority of the Roman Catholic Church, its teaching that in matters of religion each individual should use his own reason, and its putting greater stress on the ethical element in religion, was a movement in the same direction as deism. It did not, however, advance as far. To replace the authority of the Catholic Church, the Protestants substituted the Bible.

In 1784, Ethan Allen (1738-1789), the leader of the Green Mountain Boys and legendary Revolutionary War hero, and his friend Thomas Young (1731-1777) published Reason the only Oracle of Man. In their opus, America’s premier text formally introducing Deism, Allen and Young systematically dismantle the ecclesiastical foundations of New England by specifically targeting the undemocratic principles of the Congregational Church. Allen and Young wrote Reason as a revolt against the encroaching ecclesiastical domination. The duo focused upon many topics central to the European Enlightenment: substance and matter, formation versus creation, immortality, the soul, the nature and motives of prophecy, and time and eternity. Thomas Young, a student of deism, mentored a teenage Allen and instilled in him a distinctly British ideology (one based on the writings of Charles Blount and John Locke) that, paired with Allen’s upbringing in an anti-Calvinist home, materialized into America’s premier deist text.

Le protestantisme fut longtemps considéré dans l’historiographie comme le vecteur et le ferment principal des évolutions sociales et culturelles ayant accompagné l’entrée des États-Unis dans la modernité. Dans ce récit, le déisme ne constituait guère qu’un courant éphémère à l’influence mineure, voué à un inéluctable déclin. À rebours du postulat historiographique selon lequel le déisme aurait disparu au tournant des XVIIIe et XIXe siècles aux États-Unis, cette étude se propose de mettre en évidence les manières dont se transforme et se reconfigure la pensée déiste entre 1794 et 1887. À travers l’analyse de trois mouvements que sont le mesmérisme, les communautés utopiques et le spiritualisme, l’enjeu est de revisiter l’historicité du déisme américain et de ce que nous nommons ses avatars afin d’en proposer une nouvelle généalogie et de mieux cerner les sources auxquelles va puiser l’engouement actuel pour les formes de spiritualité non religieuses. Ces mouvements ne sont pas les répliques exactes du déisme mais constituent autant d’espaces propices à la perpétuation de certains principes centraux de la pensée déiste ainsi qu’à leur métabolisation. Outre qu’ils furent accusés de promouvoir l’infidélité et d’encourager l’irréligion, les avatars du déisme considérés ici ont en commun un attachement profond à l’exercice de la raison, une aversion pour les appareils ecclésiastiques et les injonctions normatives en matière politique, sociale, économique ou sexuelle ainsi qu’un scepticisme envers les manifestations surnaturelles et les vérités révélées. Ils portent, ainsi, la promesse d’une régénération du corps biologique comme du corps social et font valoir une spiritualité hors du champ des religions instituées, proche d’une forme de religion naturelle. Au croisement de la science et de la religion, ces mouvements révèlent in fine une évolution du déisme vers une spiritualité composite que nous avons pu qualifier de panenthéiste. / Scholars of American religious history have long argued that the United States channeled and developed the social and cultural forces associated with modernity through the medium of Christianity, and more specifically evangelical Protestantism. In this narrative, deism was considered a fleeting phenomenon, which had naturally disappeared at the turn of the 18th and 19th centuries. This dissertation invalidates this assertion and examines how deism remained alive while being refashioned between 1794 and 1887. Reappraising mesmerism, utopian communities and spiritualism as avatars of deism allows us to reconsider the genealogy of deist freethought and shed light on the historical influences that contributed to the forging of “spiritual but not religious” systems of belief that are on the rise in the United States nowadays. These movements cannot be considered as exact duplicates of deism ; they provide rather a favorable environment for the continuation and assimilation of central deist tenets. Besides the fact they were accused of promoting infidelity and encouraging unbelief, the avatars of deism share a strong commitment to the concept of reason, a detestation of religious authorities, social, political, economic and sexual prescriptive norms, as well as skepticism towards supernaturalism and revelation. Their members aspire to a regeneration of the social and biological body and defend a non-theological approach to spirituality, akin to a form of natural religion. At the intersection of science and religion, these movements eventually reveal an evolution of deism toward a composite, panentheistic spirituality.