Most people believe that the Creator of the universe wrote (or dictated) one of their books. Unfortunately, there are many books that pretend to divine authorship, and each makes incompatible claims about how we all must live. Despite the ecumenical efforts of many well-intentioned people, these irreconcilable religious commitments still inspire an appalling amount of human conflict.
In response to this situation, most sensible people advocate something called "religious tolerance." While religious tolerance is surely better than religious war, tolerance is not without its liabilities. Our fear of provoking religious hatred has rendered us incapable of criticizing ideas that are now patently absurd and increasingly maladaptive. It has also obliged us to lie to ourselves — repeatedly and at the highest levels — about the compatibility between religious faith and scientific rationality.
The conflict between religion and science is inherent and (very nearly) zero-sum. The success of science often comes at the expense of religious dogma; the maintenance of religious dogma always comes at the expense of science. It is time we conceded a basic fact of human discourse: either a person has good reasons for what he believes, or he does not. When a person has good reasons, his beliefs contribute to our growing understanding of the world. We need not distinguish between "hard" and "soft" science here, or between science and other evidence-based disciplines like history. There happen to be very good reasons to believe that the Japanese bombed Pearl Harbor on December 7th, 1941. Consequently, the idea that the Egyptians actually did it lacks credibility. Every sane human being recognizes that to rely merely upon "faith" to decide specific questions of historical fact would be both idiotic and grotesque — that is, until the conversation turns to the origin of books like the bible and the Koran, to the resurrection of Jesus, to Muhammad's conversation with the angel Gabriel, or to any of the other hallowed travesties that still crowd the altar of human ignorance.
Science, in the broadest sense, includes all reasonable claims to knowledge about ourselves and the world. If there were good reasons to believe that Jesus was born of a virgin, or that Muhammad flew to heaven on a winged horse, these beliefs would necessarily form part of our rational description of the universe. Faith is nothing more than the license that religious people give one another to believe such propositions when reasons fail. The difference between science and religion is the difference between a willingness to dispassionately consider new evidence and new arguments, and a passionate unwillingness to do so. The distinction could not be more obvious, or more consequential, and yet it is everywhere elided, even in the ivory tower.
Religion is fast growing incompatible with the emergence of a global, civil society. Religious faith — faith that there is a God who cares what name he is called, that one of our books is infallible, that Jesus is coming back to earth to judge the living and the dead, that Muslim martyrs go straight to Paradise, etc. — is on the wrong side of an escalating war of ideas. The difference between science and religion is the difference between a genuine openness to fruits of human inquiry in the 21st century, and a premature closure to such inquiry as a matter of principle. I believe that the antagonism between reason and faith will only grow more pervasive and intractable in the coming years. Iron Age beliefs — about God, the soul, sin, free will, etc. — continue to impede medical research and distort public policy. The possibility that we could elect a U.S. President who takes biblical prophesy seriously is real and terrifying; the likelihood that we will one day confront Islamists armed with nuclear or biological weapons is also terrifying, and it is increasing by the day. We are doing very little, at the level of our intellectual discourse, to prevent such possibilities. In the spirit of religious tolerance, most scientists are keeping silent when they should be blasting the hideous fantasies of a prior age with all the facts at their disposal.
To win this war of ideas, scientists and other rational people will need to find new ways of talking about ethics and spiritual experience. The distinction between science and religion is not a matter of excluding our ethical intuitions and non-ordinary states of consciousness from our conversation about the world; it is a matter of our being rigorous about what is reasonable to conclude on their basis. We must find ways of meeting our emotional needs that do not require the abject embrace of the preposterous. We must learn to invoke the power of ritual and to mark those transitions in every human life that demand profundity — birth, marriage, death, etc. — without lying to ourselves about the nature of reality.
I am hopeful that the necessary transformation in our thinking will come about as our scientific understanding of ourselves matures. When we find reliable ways to make human beings more loving, less fearful, and genuinely enraptured by the fact of our appearance in the cosmos, we will have no need for divisive religious myths. Only then will the practice of raising our children to believe that they are Christian, Jewish, Muslim, or Hindu be broadly recognized as the ludicrous obscenity that it is. And only then will we stand a chance of healing the deepest and most dangerous fractures in our world.