This article concerns a subject about which a great deal has been said, and over which many people have drawn battle lines. I believe, however, that I offer a different view. I myself believe that natural selection explains the origin of species. I think it is improbable that theories of irreducible complexity and intelligent design, which I shall explain and discuss here, provide answers. I also believe, however, that the introduction of these alternate theories in public school biology classes would accomplish desirable purposes-and that it could be accomplished consistently with the Constitution.