The controversy surrounding the Terri Schiavo case earlier this year surprised a number of well educated, middle-aged and older Catholics who had always been taught, from the days of Pope Pius XII (d. 1958), that no one is required to employ extraordinary means to stay alive.

Over the centuries, the concept of "extraordinary means" varied as medical technology evolved, but by the middle of the 20th century the term clearly applied to the use of a feeding tube to keep alive someone in a persistent vegetative state with no realistic hope of recovery.

A different type of Catholic, associated in one way or another with the pro-life movement and apparently unaware of this lengthy and consistent moral tradition, latched onto a talk given by the late Pope John Paul II to a group of visiting physicians in March, 2004. These Catholics interpreted the pope's remarks as if it were a definitive moral teaching on the Schiavo case, unequivocally favoring the continuation of life-support mechanisms.

Middle-aged and older Catholics have had a similar experience with regard to the current controversy over evolution-versus-intelligent design, the latter an updated version of creationism.

Catholics brought up and educated for the most part before Vatican II were taken aback when a prominent cardinal, Christoph Schönborn, archbishop of Vienna and someone who had been frequently mentioned as a possible successor to John Paul II, published an op-ed column in The New York Times ("Finding Design in Nature," July 7) that purported to give the "real" Catholic position on evolution.

The problem was that the position offered by the cardinal seemed to represent a reversal of the Catholic moral tradition on the subject of evolution, and particularly the teaching of Pope Pius XII.

Even in one of his most doctrinally rigid encyclicals, Humani Generis (1950), Pius XII explicitly approved of dialogue on the subject of evolution between scientists and theologians. He acknowledged the existence of scientific arguments in support of evolution, and insisted that the Church is open to them so long as there is no retreat from the Church's traditional teaching that "souls are immediately created by God" (n. 64).

The Second Vatican Council's Pastoral Constitution on the Church in the Modern World, Gaudium et Spes (1965), also spoke approvingly of an evolutionary framework for understanding the human condition: "the human race has passed from a rather static concept of reality to a more dynamic, evolutionary one" (n. 5).

In a 1996 address before the Pontifical Academy of Sciences in Rome, Pope John Paul II noted that the scientific case for evolution was growing stronger and that the theory was "more than a hypothesis."

Bishop Francis DiLorenzo, chair of the Committee on Science and Human Values of the U.S. Conference of Catholic Bishops, cited the pope's remarks in assuring his brother bishops that "the Church does not need to fear the teaching of evolution as long as it is understood as a scientific account of the physical origins and development of the universe."

Catholic theologians also find the scientific arguments for evolution fully compatible with the view that God creates through evolution. They have clearly distanced themselves from creationist theories which are based on a literalist reading of Genesis.

Creationism and its updated form, intelligent design, are products of faith, not scientific evidence. Their proponents act as if the Bible, narrowly interpreted, is in the same genre as scientific data.

It was later discovered that Cardinal Schönborn's op-ed piece had been solicited by the Discovery Institute in Seattle, a leading advocate for the teaching of intelligent design in biology classes, and that the article was subsequently submitted to The New York Times by a Virginia public relations firm, Creative Response Concepts, which also represents the Discovery Institute.

More recently, however, another cardinal, Paul Poupard, head of the Pontifical Council for Culture, seemed to weigh in against Cardinal Schönborn's view. He spoke at a recent news conference about "the dangers of a religion that severs its link with reason and becomes prey to fundamentalism."

Another Vatican official, Msgr. Gianfranco Basti, director of the Vatican project, Science, Theology and Ontological Quest (STOQ), reaffirmed Pope John Paul II's 1996 statement that evolution "is more than a hypothesis because there is proof."

Although Msgr. Basti agreed that the pope's statement before the Pontifical Academy of Sciences was not doctrinally definitive, neither were John Paul II's remarks on life-support mechanisms which many in the pro-life movement seized upon in the Terri Schiavo case.

In the end, as Cardinal Poupard noted, the doctrine of creation is "perfectly compatible" with evolution.

Father Richard P. McBrien is the Crowley-O'Brien Professor of Theology at the University of Notre Dame.