Having converted to Catholicism, he returned to Anglicanism in 1687. Of his numerous writings, noteworthy are: The Rights of the Christian Church against the Romish and all other priests who claim an independent power over it (published anonymously in 1706; despite its condemnation, it went through four editions in three years) and, principal among all, Christianity as old as the Creation (1730), which had a wide European influence, especially in Germany, where it was translated in 1741. This work was for many years the Bible of English deism (v.).
T. identifies Christianity with natural religion: human nature is immutable like God, who has revealed Himself to reason from the creation; hence positive Revelation is superfluous inasmuch as it adds nothing to natural revelation (the Gospel is the republication of the law of nature). There is no difference between morality and religion, inasmuch as the reason of things (according to which one acts), considered in itself and as the law of God, is identical.