He is best remembered today for his 1968 encyclical Humanae Vitae reaffirming the Church's condemnation of artificial birth control. In typical fashion, Paul VI agonized over this decision for years – more than enough time, as events soon showed, for dissent from the Church's teaching to take shape and grow. In the short term at least, the dissent that greeted Humanae Vitae was a disaster from which the Church has yet to recover.
Besides the birth control encyclical, Paul VI also produced two other remarkable documents. One of these is Populorum Progressio (The Progress of Peoples), which firmly aligned the Church with the concerns of developing nations and provided an important new chapter in Catholic social doctrine. The other is Evangelii Nuntiandi (Evangelization in the Modern World) which since its publication in 1975 – three years before Paul's death – has been a Magna Carta for Catholic evangelization.
Evangelii Nuntiandi is in part a highly sophisticated reflection on the interlocking challenges – atheism on the one hand, religious indifference on the other – that face evangelization in today's secularized world and make evangelization perhaps more needed now than ever before. Those who propose to evangelize, he wrote, must work to find "the proper means for presenting, or representing…God's revelation and faith in Jesus Christ" to their alienated contemporaries.
But there is, he wrote, a serious obstacle – "one of the great sicknesses of evangelization today" – arising from the divisions existing, as no one knew better than he, not only among separated Christians but even within the Church. Calling unity "the test of the credibility" of evangelizers, he wrote:
"If the gospel that we proclaim is seen to be rent by doctrinal disputes, ideological polarizations, or mutual condemnations among Christians, at the mercy of the latter's differing views on Christ and the Church and even because of their different concepts of society and human institutions, how can those to whom we address our preaching fail to be disturbed, disoriented, even scandalized?
"As evangelizers, we must offer Christ's faithful not the image of people divided and separated by unedifying quarrels, but the image of people who are mature in faith and capable of finding a meeting-point beyond the real tensions, thanks to a shared, sincere and disinterested search for truth."