In May 1988, a 13-year-old girl named Ashley King was admitted to Phoenix Children’s Hospital by court order. She had a tumor on her leg—an osteogenic sarcoma—that, writes Jerry Coyne in his book Faith Versus Fact, was “larger than a basketball,” and was causing her leg to decay while her body started to shut down. Ashley’s Christian Scientist parents, however, refused to allow doctors permission to amputate, and instead moved their daughter to a Christian Science sanatorium, where, in accordance with the tenets of their faith, “there was no medical care, not even pain medication.” Ashley’s mother and father arranged a collective pray-in to help her recover—to no avail. Three weeks later, she died.

Had Ashley received medical care, Coyne writes, she would likely have recovered. The Kings, tried in an Arizona court for negligent homicide, expressed no remorse, pleaded no contest, and were convicted on a lesser charge. They effectively escaped punishment, because their actions were faith-motivated. “Had the Kings been atheists,” Coyne writes, “there was a good chance [Ashley] would have lived.”

This tragic story backs up the chief argument Coyne, an evolutionary biologist at the University of Chicago, makes in Faith Versus Fact, namely that “it is time for us to stop seeing faith as a virtue, and to stop using the term ‘person of faith’ as a compliment.” In the book’s 262 pages, Coyne tackles arguments stating that belief in God is a laudable quality, and reasons instead that faith is detrimental, even dangerous, and fundamentally incompatible with science, even while peacemakers try to find common ground between the two. Coyne, it should be noted, has spent much of his career objecting to religious rejection of Darwinism—he published a bestseller, Why Evolution Is True, that was based on his blog of the same name. In Faith Versus Fact, his overarching argument is that religion and science both make claims about the universe, but only one of the two institutions is sufficiently open to the fact that it might be wrong.

In calm, levelheaded prose, Coyne refutes the “accommodationist” position that science and faith belong to “two non-overlapping magisteria”—a theory coined by his late colleague Stephen Jay Gould that espouses that science concerns itself with establishing facts about the physical universe, while religion is interested in spiritual matters, and the two therefore cannot be in conflict. Reconciling the two is impossible, he writes, because religion’s “combination of certainty, morality, and universal punishment is toxic,” while science, in contrast, acknowledges the fact that it might err, arriving at truths that are “provisional and evidence-based,” but at least testable. Unlike religion, science self-corrects, points out its errors, and tries again.

Faith Versus Fact arrives at a time when non-belief is increasing among young Americans, with a recent Pew survey showing that 34 percent of adult Millennials are unaffiliated with any particular religion—compared with 25 percent in 2007. But Americans on the whole are still largely religious, with 70.6 percent identifying as Christian in 2014. Out of those who did so, the largest group (25.4 percent) identified as Evangelical, and the survey shows that Evangelical Protestantism has lost fewer members over the past seven years than other branches of Christianity (a drop of 0.9 percent, compared with 3.1 percent for Catholicism).

One of the most significant examples of conflict between religion and science is the global-warming debate, and Coyne takes care to stress the religious roots of the arguments against climate change. He refers to Rick Santorum’s claims about it all being a “hoax” and the Illinois Representative John Shimkus’s 2009 Genesis-based testimony before a House subcommittee. Religion and climate-change denialism are inextricably linked, Coyne writes, because people of faith have a vested belief in “God’s stewardship of the planet, and his promise to preserve it until his return.” But his book was published before Pope Francis delivered an encyclical on the environment in June, warning that “climate change is a global problem with grave implications.” (The Pope was loudly criticized by politicians for doing so, but many faith leaders appear to agree with him, which somewhat undermines Coyne’s argument.) What is clear, though, is that some conservatives in the United States deny climate change on the basis of their faith.

Primarily, though, Coyne focuses on the epistemological. He notes that religion has always advanced hypotheses about the cosmos and the origins of life—matters that he argues belong within the realm of science. He bluntly evaluates faith’s record of teachings about the natural world as a “failure of religion to find out the truth about anything.” Worse, he states, faith from the start leads humans toward “thinking that an adequate explanation can be based on what is personally appealing rather than on what stands the test of empirical study.”

Coyne is clear in his argument that to understand the cosmos there is no need of a “Creator.” What science says about the temporal nature of our own solar system, in fact, renders more than improbable the existence of a divine plan for humanity. “Human tenure on Earth,” he writes, “will end when the sun … vaporize[s] the Earth in less than five billion years,” while the universe “will also end [through] heat death,” with temperatures falling to absolute zero. What does this say for those who insist there’s a divine plan for mankind on Earth? The “God of the gaps,” Coyne argues, is losing out as science fills in the missing pieces.

This rationalist understanding of life might seem cold. But Coyne isn’t out to be heartless, and recognizes the consolation religion can provide. “Your grandmother is on her deathbed,” he writes, “and is deeply consoled by thinking that she’ll soon be in heaven, reunited with her late husband and ancestors. You don’t believe a bit of it, but refrain from saying anything. What’s wrong with that?” Nothing, of course. But there’s no guarantee that faith will always be so anodyne, as he makes apparent in recounting the case of Ashley King.

Believers frequently argue that it takes faith to accept science’s improbable, occasionally inconclusive, and frequently incomprehensible deductions. Coyne dismisses this as a tu quoque dodge, a way of saying that “science is just as bad as religion,” which is in fact no argument in favor of the latter. Defenders of faith also cite the good deeds many religious people perform. But that faith at times motivates people to do good things, Coyne argues, does not outweigh the harm it causes. “We at least have plausible nonreligious explanations for all forms of altruism,” he writes, “from the least onerous to the most sacrificial.”

Coyne’s rationalist disquisition counters the popular, often hazy ideas put forward by relativist scholars, including Reza Aslan and Karen Armstrong. Aslan, for instance, contends that the Quran is meant to be seen not as literally true, but as “sacred history” and metaphor, and has even declared that “it is totally irrelevant … whether the word of God indeed poured through the lips of Muhammad.” Coyne notes that “such a statement would get one killed if uttered publicly in some Muslim lands.” Moreover, he writes, the notion that the Bible might be allegory “somehow escaped the notice of churches and theologians for centuries.”

If there’s a subject Faith Versus Fact could have dealt with in more depth, it’s the question of how people, once shorn of faith, should perceive religion’s astonishing cultural heritage, from literature and music to art and architecture. He only briefly touches on art in the context of its unsuitability as a means of ascertaining truths about the objective world because, he writes, “it lacks the tools for such inquiry.” Works of art “can move us,” he writes, “even change us, but do they convey truth or knowledge?” But he does offer telling asides about his own reaction to such things, to demonstrate that he has a heart, and isn’t just a “cold scientist.”

Faith Versus Fact could serve as a primer for nonbelievers wishing to present their case to the faithful as well as an aid for doubters struggling to resolve theistic dilemmas themselves. Atheists might hope that it could challenge believers by picking apart arguments for religion’s merits and veracity. But as his book demonstrates, and as the reactions to previous atheistic polemics by Sam Harris, Richard Dawkins, and the late Christopher Hitchens have proved, it’s unlikely to dissuade those whose faith is strongly grounded. Science might be based on a foundation of rational thought and trial-and-error, but the roots of religion lie in something much more incalculable, and thus much harder to counter.