problem of how evolutionary theory relates to the doctrine of original sin. They generally question the idea of a human fall from an original state of perfection and a common theme among them, most explicitly stated by Rahner, is to see Adam's sin as the sin of the entire human community, which provides a resolution of the problem of polygenism. Evolution in Catholic schools Catholic schools in the United States and other countries teach evolution as part of their science curriculum. They teach that evolution occurs and the modern evolutionary synthesis, which is the scientific theory that explains how evolution proceeds. This is the same evolution curriculum that secular schools teach. Bishop Francis X. DiLorenzo of Richmond, chair of the Committee on Science and Human Values, wrote in a letter sent to all U.S. bishops in December 2004: "Catholic schools should continue teaching evolution as a scientific theory backed by convincing evidence. At the same time, Catholic parents whose children are in public schools should ensure that their children are also receiving appropriate catechesis at home and in the parish on God as Creator. Students should be able to leave their biology classes, and their courses in religious instruction, with an integrated understanding of the means God chose to make us who we are." A survey of principals and teachers of science and of religion at Catholic high schools in the United States indicates some attitudes toward the teaching of evolution and the results of that teaching. 86% of principals reported their schools took an integrated approach to science and religion, in which "evolution, the Big Bang, and the Book of Genesis" were addressed together in classes. On specific topics, 95% of science teachers and 79% of religion teachers agreed that "evolution by natural selection" explains "the diversity of life on earth". Only 21% of science teachers and 32% of religion teachers believed that "Adam and Eve were real historical people". A companion survey of Catholic adults found that 65% of those who had attended a Catholic high school believed in evolution compared to 53% of those who did not attend. Unofficial Catholic organizations There have been several organizations composed of Catholic laity and clergy which have advocated positions both supporting evolution and opposed to evolution, as well as individual figures such as Bruce Chapman. For example: The Kolbe Center for the Study of Creation operates out of Mt. Jackson,