His next and best-known work, Divine Legation of Moses demonstrated on the Principles of a Religious Deist (2 vols., 1737-1741), preserves his name as the author of the most daring and ingenious of theological paradoxes.
What that work has done is to prove to the consistent deist that no objections can be drawn from reason or experience against natural or revealed religion, and, consequently, that the things objected to are not incredible and may be proved by external evidence.
Voltaire during his three years' residence in England (1726-1729) absorbed an enthusiasm for freedom of thought, and provided himself with the arguments necessary to support the deism which he had learned in his youth; he was to the end a deist of the school of Bolingbroke.
But this mission helped to make him an object of suspicion to the other members of the Committee of Public Safety, and especially to Robespierre, who as a deist and a fanatical follower of the ideas of Rousseau, hated Herault, the follower of the naturalism of Diderot.
The first specific attack on deism in English was Bishop Stillingfleet's Letter to a Deist (1677).
Though to some extent anticipated by the English deist Thomas Morgan, Semler was the first to take due note of and use for critical purposes the opposition between the Judaic and anti-Judaic parties of the early church.
The second is the typical deist of Locke's school, improved as regards his philosophy, and holding that the only possible proof of God's existence was a posteriori, from design, and that such proof was, on the whole, sufficient.