"In recent years there has been much discussion of the theory of evolution and its relation to Christian belief. This discussion has been particularly intense in the United States, but it involves theological and philosophical questions of fundamental importance to all Christians. Unfortunately, the discussion has often been conducted by people holding extreme positions and reported on by journalists interested primarily in sensationalism. As a consequence, confusion and misunderstandings abound. In this article I will attempt to clarify the issues and examine them from a Catholic point of view. Much of the confusion is created or compounded by ambiguous terminology. It is useful, therefore, to begin by clarifying terms, and most importantly the term “evolution” itself. The theory of evolution has several layers; and when people refer to “evolution” in the current controversies, it is not always clear to which layer they are referring. First, there is the evolution of species, the idea that the present species of plants and animals arose from other species by a gradual process, and that ultimately all of them came from a single original form of life. This is sometimes called the theory of “common descent”, since it says that all living things descended from a common ancestor. Second, there is human evolution, the idea that human beings evolved in the same way and are thus part of the same branching tree of life. Finally, there is the Darwinian mechanism, the idea that evolution is driven by natural selection acting on random genetic mutations."(...)