The Brief History of a Soul is the story of a lively debate whose arguments, vocabulary, and even subject have evolved over millennia. In this historical narrative cum apologia, Stewart Goetz and Charles Taliaferro champion “substance dualism,” a philosophical position that asserts the ontologically distinct reality of matter and soul (or body and mind in post-Cartesian terms). They largely succeed in their efforts to be “fair and balanced” (4) and succeed in presenting a sophisticated and nuanced yet readable account of the controversy in its philosophical and, to some extent, theological and scientific dimensions. As entailed by the “Brief” caveat, they maintain a disciplined focus on a relatively few major players in this saga of the soul. Early in the book, the authors capture just how unstable the concept of “soul” has been in Western thought. Classical thought had already ranged from Plato's independently (and pre-) existing soul as discrete entity, to Aristotle's non-dualistic version of the human soul as the formed aspect of the body. Their decision to discuss only Plato and Aristotle among pre-medieval thinkers is reasonable; less defensible is their curious omission of a substantial line of thought in philosophy and theology that is both important to thinking about the soul in its own right, and especially pertinent to soul-related issues that the authors engage: free will. A commonplace among Christian Fathers especially was the question of the soul's origin. Origen, first church theologian, believed that question was first in priority after addressing the topic of the Trinity itself (On First Principles). Augustine, as the authors note in chapter 2 (45), postulates four possibilities: traducianism (physical procreation of the soul by parents), creationism (special creation by God at birth), sent preexistence (God sends preexisting souls to be embodied) and fallen preexistence (human choices result in the embodiment of their preexisting souls). The authors address the merits of theories 1 and 2, but inexplicably drop here and for the remainder of the book the other two options, although the theory of the soul's premortal existence figures prominently with the thought of dozens of subsequent philosophers and theologians, many of whom they discuss. For Plato the idea provided theodicy (Republic X). Augustine long favored preexistence as carrying less theological baggage than the alternatives and only retreated from the idea when grace became a greater theological concern than free will. The authors mention Henry More's unconventional defense of a soul that was spatially extended, but neglect his emphatic defense—along with a whole cohort of Cambridge Platonists—of a preexistent soul. Locke found his theory of memory-based human selfhood to render preexistence moot, and Kant, whom the authors discuss along with all the above named, found the soul's preexistence essential to human agency. In the twentieth century as well, philosophers like John McTaggart argued any conception of a human soul that did not posit its preexistence could not adequately ground a theory of free will, which is clearly of great import to Goetz and Taliaferro.

More important to these authors is a sustained defense of dualism itself; a principal form this takes today is to insist that an immaterial soul is the most effective solution to the “bundling problem” (87). David Berlinski articulates one version of this dilemma: “How do the twitching nerves, chemical exchanges, electrical flashes, and computational routines of the human eye and brain provide a human being with experience? The gap opened between causal sequences that with a moving finger we can trace from one point to the next and the light-enraptured awareness to which they give rise is unfathomably large because it spans an incommensurable distance” (David Berlinski, The Devil's Delusion: Atheism and its Scientific Pretensions [New York: Crown Forum, 2008] 204). The consistent historical description of a soul that is “simple in nature” does not just result from the questionable metaphysics of immaterial substance, but answers to the lived phenomenon of first-person experience and the unity of consciousness.

Goetz and Taliaferro also devote considerable time on dualism's principal vulnerability: the mind-body problem. Though Aquinas gives it passing attention, it remained for Descartes to give it its enduring form—interaction with a body presupposes extension and contact, both of which are excluded by immateriality. Though he tentatively located the node of maximum interpenetration of mind and body in the pineal gland, he confessed “we have no notion” of how causal interaction occurred (81). The authors do not know either, but they are convinced that neither philosophy nor contemporary science have found compelling arguments against the soul or against mind-body interaction. Regarding science, their argument is largely a matter of explaining why most recent developments are irrelevant to the debate; mapping brain functions tells us much about cerebral geography, but the real issue in current debates about the nature of mind has to do with causal closure. This doctrine holds that all physical events have causes originating in the physical domain; and since mental events are really physical in nature, there is no necessity (or room) for non-physical causes originating in mind or soul to explain physical events. The authors show why this argument is more about a naturalist set of presuppositions than scientific method per se.

One of the book's questionable steps is to buttress the argument against causal closure by noting it is irreconcilable with any “explanatory space for God” (175). What they present as an warning of logical inconsistency to Christian advocates of causal closure sounds dangerously like an argument from faith in the context of their larger polemic, their disclaimer notwithstanding. Similarly, they (and Thomas Nagel) may be right that some critics of Intelligent Design misread their own naturalistic assumptions (that is, causal closure) as simply good science. But the controversial distraction of Intelligent Design can only detract from this book's larger purposes. And those larger purposes—tracing the history of the soul and revealing the idea to be as timely and viable today as it was for Plato and Augustine—are commendably executed.