In the nineteenth and early twentieth century, the challenge came in the form of Darwinism and its seeming opposition to biblical religion, a battle initiated not so much by the scientists as by the beleaguered defenders of orthodoxy. In our own time, the challenge comes from molecular biology, behavioral genetics and evolutionary psychology, fueled by their practitioners’ overconfident belief in the sufficiency of their reductionist explanations of all vital and human phenomena. Never mind “created in the image of God”; what elevated humanistic view of human life or human goodness is defensible against the belief, asserted by most public and prophetic voices of biology, that man is just a collection of molecules, an accident on the stage of evolution, a freakish speck of mind in a mindless universe, fundamentally no different from other living – or even nonliving – things? What chance have our treasured ideas of freedom and dignity against the reductive notion of “the selfish gene” (or, for that matter, of “genes for altruism”), the belief that DNA is the essence of life, or the teaching that all human behavior and our rich inner life are rendered intelligible only in terms of their contributions to species survival and reproductive success?
Leon R. Kass – Life, Liberty, and the Defense of Dignity: The Challenge for Bioethics p.135