Thanks to the theory of evolution, naturalism is now the dominant religion of modern society. Less than a century and a half ago, Charles Darwin popularized the credo for this secular religion with his book The Origin of Species. Although most of Darwin's theories about the mechanisms of evolution were discarded long ago, the doctrine of evolution itself has managed to achieve the status of a fundamental article of faith in the popular modern mind. Naturalism has now replaced Christianity as the main religion of the Western world, and evolution has become naturalism's principal dogma.
Naturalism is the view that every law and every force operating in the universe is natural rather than moral, spiritual, or supernatural. Naturalism is inherently anti-theistic, rejecting the very concept of a personal God. Many assume naturalism therefore has nothing to do with religion. In fact, it is a common misconception that naturalism embodies the very essence of scientific objectivity. Naturalists themselves like to portray their system as a philosophy that stands in opposition to all faith-based world-views, pretending that it is scientifically and intellectually superior precisely because of its supposed non-religious character.
Not so. Religion is exactly the right word to describe naturalism. The entire philosophy is built on a faith-based premise. Its basic presupposition--an a priori rejection of everything supernatural--requires a giant leap of faith. And nearly all its supporting theories must be taken by faith as well. (See below.)
Consider the dogma of evolution, for example. The notion that natural evolutionary processes can account for the origin of all living species has never been and never will be established as fact. Nor is it "scientific" in any true sense of the word. Science deals with what can be observed and reproduced by experimentation. The origin of life can be neither observed nor reproduced in any laboratory. By definition, then, true science can give us no knowledge whatsoever about where we came from or how we got here. Belief in evolutionary theory is a matter of sheer faith. And dogmatic belief in any naturalistic theory is no more "scientific" than any other kind of religious faith.
Michael Ruse is an evolutionist who testified in the 1980s at the infamous Arkansas creationism trial (McLean v. Arkansas). During the trial, he claimed that creationism is a religion because it is grounded in unproven philosophical assumptions. But Darwinism is a science, he said, because it requires no philosophical or religious presuppositions. Ruse has since admitted that he was wrong, and he now acknowledges that evolution "is metaphysically based"--grounded in unproven beliefs that are no more "scientific" than the set of beliefs on which creationism is based. See Tom Woodward, "Ruse Gives Away the Store: Admits Evolution Is a Philosophy" on the "Origins" Web site.