He was not, however, to be moved by such means, and (1792) issued his work Die Religion der Vollkommeneren, an exposition of his theological position, in which he advocated at length the idea, subsequently often urged, of "the perfectibility of Christianity," - that is, of the ultimate transformation of Christianity into a scheme of simple morality, with a complete rejection of all specifically Christian ideas and methods.
The aim of his inquiries was to promote the happiness of mankind, which could be better accomplished by pointing out the real possibilities of progress than by indulging in vague dreams of perfectibility apart from the actual facts which condition human life.
Malthus's Essay on Population grew out of some discussions which he had with his father respecting the perfectibility of society.
Believing in the perfectibility of the race, that there are no innate principles, and therefore no original propensity to evil, he considered that "our virtues and our vices may be traced to the incidents which make the history of our lives, and if these incidents could be divested of every improper tendency, vice would be extirpated from the world."
On the 1st of May 418 a great synod ("A Council of Africa," St Augustine calls it), which assembled under the presidency of Aurelius, bishop of Carthage, to take action concerning the errors of Caelestius, a disciple of Pelagius, denounced the Pelagian doctrines of human nature, original sin, grace and perfectibility, and fully approved the contraryviews of Augustine.