Yes, there is a bit of arrogance here, but in the view of the atheists and the brights, it is justified. Long considered a marginal and reticent minority, atheists are now lashing out at religion with enormous gusto. Nobel laureate Steven Weinberg writes, “Anything that we scientists can do to weaken the hold of religion should be done and may in the end be our greatest contribution to civilization.” Sam Harris in The End of Faith condemns what he terms “the lunatic influence of religious belief.” Christopher Hitchens writes, All religions and all churches are equally demented in their belief in divine intervention, divine intercession, or even the existence of the divine in the first place.” Dawkins adds, “The great unmentionable evil at the center of our culture is monotheism. From a barbaric Bronze Age text known as the Old Testament, three anti-human religions have evolved: Judaism, Christianity, and Islam.”

What gives the atheists such confidence? The answer, in a word, is science. Many atheists believe that modern science—the best known way to accumulate knowledge, the proven technique for giving us airplanes and computers and drugs that kill bacteria—has vindicated the nonbeliever’s position. And it seems that a majority of scientists in the United States are atheists. Only 40 percent—a sizable minority, but a minority nevertheless—believe in a personal God. And among members of the elite National Academy of Sciences, only 7 percent of scientists can be counted among the ranks of the believers.” These figures have remained generally consistent over several decades, with the proportion of atheists rising slightly.

But what is it about science that supports atheism? For one, science seems to work better than religion. “We can pray over the cholera victim,” Carl Sagan writes, “or we can give her 500 milligrams of tetracycline every twelve hours.” In such cases, Sagan points out, even Christians are likely to supplement their prayers with medicine. Another reason, according to Steven Pinker, is that “the modern sciences of cosmology, geology, biology, and archaeology have made it impossible for a scientifically literate person to believe that the biblical story of creation actually took place.” While science relies on the principle that “nothing is more sacred than the facts,” Sam Harris charges that “theology is now little more than a branch of human ignorance. Indeed it is ignorance with wings.”

In making their case, the atheists often appeal to the revolutionary influence of Charles Darwin. In his book The Blind Watchmaker, Dawkins writes that “Darwin made it possible to be an intellectually fulfilled atheist.” He points out that the universe and its creatures show irrefutable evidence of design. Before Darwin, there was no plausible explanation for that design other than to posit a designer. So atheists had no way to account for life’s diversity and complexity. Many—including skeptic David Hume—were forced to concede that each creature was fitted with the equipment needed for its survival by some sort of higher being.

The great achievement of Darwin’s theory of evolution and natural selection, Dawkins and others say, is that it shows how creatures that appear to be designed have in fact evolved according to the pressures of chance and survival. Atheists now have an alternative explanation for why fish have gills, why birds have wings, and why human beings have brains and arms and lungs. Indeed, in the atheist view, evolution refutes the biblical account of human creation, exposing it as a crude and primitive myth. Carl Sagan remarks that “as science advances, there seems to be less and less for God to do…. Whatever it is we cannot explain lately is attributed to God…. And then after a while, we explain it, and so that’s no longer God’s realm.’ This is none other than the God of the Gaps, who is forced by science into ever greater irrelevance. Dawkins argues that contrary to the claims of religion, we humans “are survival machines—robot vehicles blindly programmed to preserve the selfish molecules known as genes.”