An influential cardinal in the Roman Catholic Church, which has long been regarded as an ally of the theory of evolution, is now suggesting that belief in evolution as accepted by science today may be incompatible with Catholic faith.

Cardinal Christoph Schönborn, pictured at the Vatican in 2003, said students should be taught that evolution is just one of many theories.

The cardinal, Christoph Schönborn, archbishop of Vienna, a theologian who is close to Pope Benedict XVI, staked out his position in an Op-Ed article in The New York Times on Thursday, writing, "Evolution in the sense of common ancestry might be true, but evolution in the neo-Darwinian sense - an unguided, unplanned process of random variation and natural selection - is not."

In a telephone interview from a monastery in Austria, where he was on retreat, the cardinal said that his essay had not been approved by the Vatican, but that two or three weeks before Pope Benedict XVI's election in April, he spoke with the pope, then Cardinal Joseph Ratzinger, about the church's position on evolution. "I said I would like to have a more explicit statement about that, and he encouraged me to go on," said Cardinal Schönborn.

He said that he had been "angry" for years about writers and theologians, many Catholics, who he said had "misrepresented" the church's position as endorsing the idea of evolution as a random process.

Opponents of Darwinian evolution said they were gratified by Cardinal Schönborn's essay. But scientists and science teachers reacted with confusion, dismay and even anger. Some said they feared the cardinal's sentiments would cause religious scientists to question their faiths.

Cardinal Schönborn, who is on the Vatican's Congregation for Catholic Education, said the office had no plans to issue new guidance to teachers in Catholic schools on evolution. But he said he believed students in Catholic schools, and all schools, should be taught that evolution is just one of many theories. Many Catholic schools teach Darwinian evolution, in which accidental mutation and natural selection of the fittest organisms drive the history of life, as part of their science curriculum.

Darwinian evolution is the foundation of modern biology. While researchers may debate details of how the mechanism of evolution plays out, there is no credible scientific challenge to the underlying theory.

American Catholics and conservative evangelical Christians have been a potent united front in opposing abortion, stem cell research and euthanasia, but had parted company on the death penalty and the teaching of evolution. Cardinal Schönborn's essay and comments are an indication that the church may now enter the debate over evolution more forcefully on the side of those who oppose the teaching of evolution alone.

One of the strongest advocates of teaching alternatives to evolution is the Discovery Institute in Seattle, which promotes the idea, termed intelligent design, that the variety and complexity of life on earth cannot be explained except through the intervention of a designer of some sort.

Mark Ryland, a vice president of the institute, said in an interview that he had urged the cardinal to write the essay. Both Mr. Ryland and Cardinal Schönborn said that an essay in May in The Times about the compatibility of religion and evolutionary theory by Lawrence M. Krauss, a physicist at Case Western Reserve University in Cleveland, suggested to them that it was time to clarify the church's position on evolution.

The cardinal's essay was submitted to The Times by a Virginia public relations firm, Creative Response Concepts, which also represents the Discovery Institute.

Mr. Ryland, who said he knew the cardinal through the International Theological Institute in Gaming, Austria, where he is chancellor and Mr. Ryland is on the board, said supporters of intelligent design were "very excited" that a church leader had taken a position opposing Darwinian evolution. "It clarified that in some sense the Catholics aren't fine with it," he said.

Bruce Chapman, the institute's president, said the cardinal's essay "helps blunt the claims" that the church "has spoken on Darwinian evolution in a way that's supportive."

But some biologists and others said they read the essay as abandoning longstanding church support for evolutionary biology.

"How did the Discovery Institute talking points wind up in Vienna?" wondered Glenn Branch, deputy director of the National Center for Science Education, which advocates the teaching of evolution. "It really did look quite a bit as if Cardinal Schönborn had been reading their Web pages."

Mr. Ryland said the cardinal was well versed on these issues and had written the essay on his own.

Dr. Francis Collins, who headed the official American effort to decipher the human genome, and who describes himself as a Christian, though not a Catholic, said Cardinal Schönborn's essay looked like "a step in the wrong direction" and said he feared that it "may represent some backpedaling from what scientifically is a very compelling conclusion, especially now that we have the ability to study DNA."

"There is a deep and growing chasm between the scientific and the spiritual world views," he went on. "To the extent that the cardinal's essay makes believing scientists less and less comfortable inhabiting the middle ground, it is unfortunate. It makes me uneasy."

"Unguided," "unplanned," "random" and "natural" are all adjectives that biologists might apply to the process of evolution, said Dr. Kenneth R. Miller, a professor of biology at Brown and a Catholic. But even so, he said, evolution "can fall within God's providential plan." He added: "Science cannot rule it out. Science cannot speak on this."

Dr. Miller, whose book "Finding Darwin's God" describes his reconciliation of evolutionary theory with Christian faith, said the essay seemed to equate belief in evolution with disbelief in God. That is alarming, he said. "It may have the effect of convincing Catholics that evolution is something they should reject."

Dr. Collins and other scientists said they could understand why a cleric might want to make the case that, as Dr. Collins put it, "evolution is the mechanism by which human beings came into existence, but God had something to do with that, too." Dr. Collins said that view, theistic evolution, "is shared with a very large number of biologists who also believe in God, including me."

But it does not encompass the idea that the workings of evolution required the direct intervention of a supernatural agent, as intelligent design would have it.

In his essay, Cardinal Schönborn asserted that he was not trying to break new ground but to correct the idea, "often invoked," that the church accepts or at least acquiesces to the theory of evolution.

He referred to widely cited remarks by Pope John Paul II, who, in a 1996 address to the Pontifical Academy of Sciences, noted that the scientific case for evolution was growing stronger and that the theory was "more than a hypothesis."

In December, Bishop Francis X. DiLorenzo, chairman of the Committee on Science and Human Values of the United States Conference of Catholic Bishops, cited those remarks in writing to the nation's 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." But in his essay, Cardinal Schönborn dismissed John Paul's statement as "rather vague and unimportant."

Francisco Ayala, a professor of biology at the University of California, Irvine, and a former Dominican priest, called this assessment "an insult" to the late pope and said the cardinal seemed to be drawing a line between the theory of evolution and religious faith, and "seeing a conflict that does not exist."

Dr. Miller said he was already hearing from people worried about the cardinal's essay. "People are saying, does the church really believe this?" He said he would not speculate. "John Paul II made it very clear that he regarded scientific rationality as a gift from God," Dr. Miller said, adding, "There are more than 100 cardinals and they often have conflicting opinions."