The Vatican and the U.S. Conference of Catholic Bishops are investigating the work of a theologian at Georgetown University, the Rev. Peter C. Phan, whose writings have analyzed and celebrated the expansion of religious pluralism.

That work, according to the National Catholic Reporter, contradicts one of the Vatican’s chief bugbears under Pope John Paul II and especially since the election of his successor, Pope Benedict XVI: religious relativism.

The Vatican is focusing its scrutiny on Father Phan’s book Being Religious Interreligiously (Orbis, 2004). In a letter to him in 2005, the Vatican asserted that the book “is notably confused on a number of points of Catholic doctrine and also contains serious ambiguities,” according to anonymous sources who spoke with the National Catholic Reporter.

Father Phan, a native of Vietnam, is a former president of the Catholic Theological Society of America. In an essay that touches on some themes of his book, he writes, “A pluralistic theology serves as a strong reminder to Christians that non-Christian religious traditions may and indeed do contain teachings and practices that will help Christians know and love God.” —John Gravois and Thomas Bartlett