This month marks the 50th anniversary of the opening of the Second Vatican Council, that momentous worldwide summit that shaped Catholicism as we know it today. The 2,500 or so participants in that four-year meeting accomplished more than anyone dared imagine beforehand. The 16 major documents they produced reformed the liturgy, put ecumenism on the agenda and committed the Catholic church to support religious freedom for the first time. Life in the church would never be the same.

As a Catholic theologian, I am especially eager to affirm the directions of the council and defend its achievements against charges one hears from traditionalists these days, that its embrace of modernity was indiscriminate -- an unwise betrayal of the Catholic tradition. On the contrary, when the council fathers affirmed the crucial dialogue between church and world, they were advancing the very best of our tradition.

The legacy of Vatican II is sharply contested by progressives and traditionalists. Whether you are impatient for the reforms promised by Vatican II to unfold further or whether you would prefer to roll back some of its teachings, you have to tip your hat and recognize the impact of the transformational achievement forged by all those bishops gathered in Rome in the early 1960s. Their work was sparked by the jolly persona of John XXIII, the pope who called the council in order to "let a bit of fresh air in through the stained glass windows."

For centuries, Catholic moral theology had been dominated by a near-obsession with sin and rebuking enemies of the faith. It was far clearer what an embattled church stood against -- what was anathema -- than what Catholics stood for and what they should yearn for in the moral life. In documents like the 1864 Syllabus of Errors, church authorities issued sweeping condemnations of freethinking ideas that challenged the laws and social norms laid down by popes and bishops. Galileo was far from the only voice silenced by church disciplinary action.

By replacing words like anathema with terms like dialogue, collegiality, communion and participation -- words that evoke dynamic openness rather than static essences -- the council fathers thoroughly revived the creative side of Catholic ethics. The seriously constricted moral imagination of the faithful could now move beyond the previous preoccupation with law, sin and culpability and focus more upon moral freedom, the virtues, spiritual discernment, and above all, the role of conscience in the moral life.

One especially striking direction was Vatican II's emphasis on the inner depths of people as they attempt to lead admirable and socially responsible lives. This presumed that in forming and acting upon conscience, people of good will deliberate, consult, change their minds and yearn for relationships that are deeper and ever more fulfilling and faithful.

Ultimately, Vatican II spurred Catholicism to wake up to a more modest, less smug version of itself. It no longer pretended to hold a monopoly on all the answers, and it began to recognize the promise of learning valuable lessons from the wider world beyond the church vestibule. The church began to identify itself with the modern world, especially with the plight of the poorest among us, as it pursued social justice and solidarity with new energy and urgency. It began to understand itself as a world church, no longer solely grounded in Europe, but now open to the vitality of the global south. Catholicism would no longer be satisfied with constructing defensive walls against dangerous ideas but would actively seek to engage secular movements and to embrace worldly achievements. As Vatican II took up questions about the role of the laity, the proper basis for church-state relations and much else, many observers readily noted this outward turn.

In the heady days at the opening of the Second Vatican Council in 1962, nobody could predict just how the deliberations would combine the old and the new, drawing together traditional Christian sources with innovative insights. At the distance of half a century now, it is clear that the council fathers crafted a creative brew in which the flavor of the familiar is enhanced by new ingredients. In the field of moral theology and many others, we all still benefit immensely from the work of the council.

[Jesuit Fr. Thomas Massaro is a theologian and dean of Jesuit School of Theology at Berkley of Santa Clara University in California.]