Leading biologists spell out some of the implications. As Darwin has shown how life is “the result of a natural process,” Francisco Ayala writes, we are “without any need to resort to a Creator.”” In an essay on evolution and its implications, William Provine writes, “Modern science directly implies that there are no inherent moral or ethical laws, no absolute guiding principles for human society…. We must conclude that when we die, we die, and that is the end of us.”

Many scientific atheists portray man as simply a carbon-based machine, a purely material object whose belief in immaterial things is a kind of epiphenomenon or illusion. Biologist Francis Crick, who helped to discover the structure of DNA, writes that all biology is reducible to the laws of physics and chemistry. Life is the product of the same mechanical operations as the inanimate matter in nature. Consciousness is “no more than the behavior of a vast assembly of nerve cells and their associated molecules.” Biologist E. 0. Wilson writes that the hidden operations of our mental activity give us “the illusion of free will.”

For centuries, cognitive scientist Steven Pinker points out, religion has taught men to believe in an immortal soul that inhabits our bodies, a kind of “ghost in the machine.” But modern science has, in Pinker’s view, destroyed that belief. “The mind is the physiological activity of the brain” and “the brain, like other organs, is shaped by the genes” and those have been “shaped by natural selection and other evolutionary processes.” Therefore the mind is nothing more than “an entity in the physical world, part of a causal chain of physical events:’ When the brain decays through aging or disease, the mind disappears. As for the soul? Pinker ringingly declares that “the ghost in the machine has been exorcised.”