John Henry Cardinal Newman begins the Essay by defining how true developments in doctrine occur. He then delivers a sweeping consideration of the growth of doctrine in the Catholic Church from the time of the Apostles to his own era. He demonstrates that the basic “rule” under which Christianity proceeded through the centuries is to be found in the principle of development, and he emphasizes that throughout the entire life of the Church this principle has been in effect and safeguards the faith from any corruption.
Ian Ker is a member of the theology faculty at Oxford University. His many works include The Catholic Revival in English Literature, 1845-1961 (University of Notre Dame Press, 2003).