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.”