FORTY years ago, as the reforming Second Vatican Council moved towards its conclusion, intense discussion surrounded one of its documents.

The Pastoral Constitution on the Church in the Modern World, known from the first words of the Latin version as Gaudium et Spes (Joy and Hope), was without precedent. It witnessed to the Church’s changed understanding of its place in the world, in accordance with Pope John XXIII’s wish that the Council should serve “humanity as such, and not just Catholics”, and should defend “above all else and everywhere, the rights of the human person and not just those of the Catholic Church”.

Pope John Paul II always maintained that the council’s work was the foundation of his papacy. For 26 years as Pope until his death in April, Gaudium et Spes was his agenda. He presented Christ as the key to being truly human, and human rights were the platform of his preaching in every continent.

This was new. In the 19th century and well into the 20th, the Catholic Church had taken up a defensive position against the world, claiming to be a society complete in itself, set above the flux of human history like a lighted castle on a hill. From the security of its precincts Christian knights would venture out to pluck lost souls from the morass and convey them to salvation. As for human rights, these had been perceived by Catholics as a secularising master stroke dealt by the French Revolution, designed to oust the Church from the marketplace and replace it with worldly ethics and law. In riposte, Catholics would appeal to duties, and sometimes to the rights of God.

Vatican II took a different line. Persuaded by Pope John, the Church now understood itself to be a pilgrim with all humanity, bearing a message which it wanted to share through a respectful dialogue and conversation. Gaudium et Spes set the tone with its memorable opening: “The joys and the hopes, the griefs and the anxieties of the people of this age, especially those who are poor or in any way afflicted, these too are the joys and hopes, the griefs and anxieties of the followers of Christ. Indeed, nothing genuinely human fails to raise an echo in their hearts.”

This pioneering pastoral constitution has two parts. The first sets out a theological basis for the Christian humanism that inspires the whole text. It is a sustained meditation on how Jesus reveals what it is to be truly human. Gaudium et Spes highlights the paradox by which men and women feel a “sense of sorrow, of evil, of death, which continues to exist despite so much progress”. The “riddle of human existence” points beyond itself: it can only be illuminated, says Gaudium et Spes, by the mystery of the incarnate Christ who “united Himself in some fashion” with every human being — “He worked with human hands, thought with a human mind, acted by human choice, and loved with a human heart.” In this perspective the constitution speaks of “the human family and its history”, and of the Church’s conviction that it can contribute greatly to making that family and history more human.

In its second part the constitution sets itself to read “the signs of the times” — a favourite pastoral method of Pope John — and in the light of them looks in turn at “problems of special urgency”, including marriage and the family, the development of culture, economics, politics, warfare and international relations. It thus reasserts on the one side that grace is at work not only in psychology but in society and history, and on the other repudiates the secularist thesis that religion has no relevance beyond the private sphere.

Along these lines John Paul II established the Catholic Church as a dynamic world force. Here was Gaudium et Spes in action. That stance was part of the reason for the outpouring of respect, admiration and fellow feeling that surrounded his death.

We wait now for evidence of what Benedict XVI’s agenda will be. Though he wrote one of the best commentaries on Gaudium et Spes, he has expressed strong reservations about its “astonishing optimism”. There is a fear that the Council’s vision will be denied, but Pope Benedict will not do that. He has insisted that Vatican II’s authority is as great as that of Vatican I or Trent.

Pope John XXIII can still have the last word. “It is not the Gospel that changes,” he said. “It is we who are beginning to understand it better.”

John Wilkins was Editor of The Tablet, 1982-2003