There are plenty of books that make the case for atheism, but Alex Rosenberg's The Atheist's Guide to Reality isn't one of them. The American philosopher maintains that religious belief is immune to rational objection. There's little point, argues Rosenberg, in preaching to the unconverted. His aim is to enlighten the converted by arguing for what an atheist should believe, since there's more to atheism than simply "there is no God". He begins by rebranding atheism as "scientism" so as to better describe what atheists "do believe". First, an atheist has to understand the science, then accept its "irrefutably correct answers to the persistent questions". What is the nature of reality? What physics says it is. What is the purpose of the universe? There is none. What is the meaning of life? Ditto.
Rosenberg's scientism is built on accepting well-established laws of physics as the basic description of reality. He argues that the physics tells us just about everything we need to know about how the universe works. We can extend this to chemistry and biology, and then, with an appeal to Darwinian processes, everything else. For Rosenberg, almost everything we think of as having inherent value or meaning, from morality to the idea of a self, does not. He wants us to let go of our many illusions, such as the concept of free will. Being "scientistic" means treating science as the "exclusive guide to reality" and accepting that it "enables atheism to answer life's universal and relentless questions".
Rosenberg argues that atheists are assailed on all sides by attempts to sow doubt about the completeness and credibility of science. Worse still, some of those questioning the reach of science are people with impeccable scientific qualifications. Rosenberg wants to clarify "what our attachment to science... really commits us to".
There's much that Rosenberg writes one can agree with; as for the rest, it's at least thought-provoking. If you can't swallow science's answers as interpreted by Rosenberg, he has one last piece of advice: "Take a Prozac or your favourite serotonin reuptake inhibitor, and keep taking them till they kick in."