Stephen Layman of Seattle Pacific University has penned a spirited series of letters, between fictional correspondents Thomas and Zach, touching on various aspects of the philosophy of religion. As motivation for the exchange, Layman's Zach sets himself the task of convincing Thomas that "theism" - which he defines as belief in the necessary existence of a unique, perfectly good and omnipotent being - is a more convincing hypothesis than "naturalism" - the belief that there exists nothing beyond the physical world.
Together the pair explore a number of the factors that have traditionally been held to support or undermine the two positions, including mystical experience, the problem of necessary existence, cosmological fine-tuning, the question of free will, the problem of natural and moral evil, the appearance of design in nature, and the Euthyphro dilemma. Zach's initial statement of the issues surrounding each topic is in most cases clear and even-handed, and for this reason alone the book offers a useful introduction to the philosophy of religion for the freshman student and casual reader alike. Layman's dialog format also helps bring to life material that would otherwise often be technical and dull.
However, as each chapter develops Zach's balance quickly falls away to be replaced by a one-sided defense of theism, and Thomas rarely points out the many weaknesses and inconsistencies in his arguments (the only major exception has Thomas shooting down Zach's first attempt at framing an ontological argument for the existence of God in Chapter 9). Many of the rhetorical maneuvers Zach uses - such as appealing to the extreme claim that only a perfectly good creator can guarantee human cognitive reliability to stave off suggestions that God is morally indifferent, or insisting that naturalism cannot explain evil because it cannot explain life at all - smack more of apologetics than mainstream philosophy. And Zach's solution of the problem of evil commits him to the odd belief that (some) animals will experience life after death "if God's purposes [for them] are not fulfilled prior to death" [p. 202], a proposition that few theologians would likely embrace.
Moreover, Layman's Zach seems to be unaware that naturalists play this particular philosophical game with quite different ground rules. At one point in Chapter 8, Zach concludes a passage critical of naturalism's failure so far to explain the origin of life with the hedging remark "Let me hasten to add that if life did arise from natural causes, there is no reason for Theists to deny this" [pp. 211-212]. Far from being a point in favor of theism, most naturalists would regard this as a black mark against it. As the mathematician Pierre-Simon Laplace famously retorted more than 200 years ago, "the precise difficulty with the hypothesis [of a creator]" is that "it explains everything, but predicts nothing".