Ideas of this general character were voiced on the Continent at about the same period by such men as Pierre Bayle, a French philosopher famous for his encyclopaedic dictionary, even though he would have rejected the Deist identification. During the heyday of the French Philosophes in the 18th century, the more daring thinkers—Voltaire among them—gloried in the name Deist and declared the kinship of their ideas with those of Rationalist English ecclesiastics, such as Samuel Clarke, who would have repudiated the relationship. The dividing line between Deism and atheism among the Philosophes was often rather blurred, as is evidenced by Le Rêve de d’Alembert (written 1769; “The Dream of d’Alembert”), which describes a discussion between the two “fathers” of the Encyclopédie: the Deist Jean Le Rond d’Alembert and the atheist Diderot. Diderot had drawn his inspiration from Shaftesbury, and thus in his early career he was committed to a more emotional Deism. Later in life, however, he shifted to the atheist materialist circle of the baron d’Holbach. When Holbach paraphrased or translated the English Deists, his purpose was frankly atheist; he emphasized those portions of their works that attacked existing religious practices and institutions, neglecting their devotion to natural religion and their adoration of Christ. The Catholic church in 18th-century France did not recognize fine distinctions among heretics, and Deist and atheist works were burned in the same bonfires.

English Deism was transmitted to Germany primarily through translations of Shaftesbury, whose influence upon thought was paramount. In a commentary on Shaftesbury published in 1720, Gottfried Wilhelm Leibniz, a Rationalist philosopher and mathematician, accepted the Deist conception of God as an intelligent Creator but refused the contention that a god who metes out punishments is evil. A sampling of other Deist writers was available particularly through the German rendering of Leland’s work in 1755 and 1756. H.S. Reimarus, author of many philosophical works, maintained in his Apologie oder Schutzschrift für die vernünftigen Verehrer Gottes (“Defense for the Rational Adorers of God”) that the human mind by itself without revelation was capable of reaching a perfect religion.

Reimarus did not dare to publish the book during his lifetime, but it was published in 1774–78 by Gotthold Ephraim Lessing, one of the great seminal minds in German literature. According to Lessing, common man, uninstructed and unreflecting, will not reach a perfect knowledge of natural religion; he will forget or ignore it. Thus, the several positive religions can help men achieve more complete awareness of the perfect religion than could ever be attained by any individual mind. Lessing’s Nathan der Weise (1779; “Nathan the Sage”) was noteworthy for the introduction of the Deist spirit of religion into the drama; in the famous parable of the three rings, the major monotheistic religions were presented as equally true in the eyes of God.

Although Lessing’s rational Deism was the object of violent attack on the part of Pietist writers and more mystical thinkers, it influenced such men as Moses Mendelssohn, a German Jewish philosopher who applied Deism to the Jewish faith. Immanuel Kant, the most important figure in 18th-century German philosophy, stressed the moral element in natural religion when he wrote that moral principles are not the result of any revelation but rather originate from the very structure of man’s reason. English Deists, however, continued to influence German Deism. Witnesses attest that virtually the whole officer corps of Frederick the Great was “infected” with Deism and that Collins and Tindal were favourite reading in the army.

By the end of the 18th century, Deism had become a dominant religious attitude among intellectual and upper-class Americans. Benjamin Franklin, the great sage of the colonies and then of the new republic, summarized in a letter to Ezra Stiles, president of Yale College, a personal creed that almost literally reproduced Herbert’s five fundamental beliefs. The second and third presidents of the United States also held Deistic convictions, as is amply evidenced in their correspondence. “The ten commandments and the sermon on the mount contain my religion,” John Adams wrote to Thomas Jefferson in 1816.