Kevin Diller argues that Christian theology faces an epistemic dilemma rooted in two necessary but conflicting affirmations. On the one hand, we must affirm that the knowledge of God is a real human possibility; on the other hand, we must concede that humans are unable to secure this knowledge on their own due to their inadequacy and fallibility. So how do we claim that God truly can be known while also accounting for the intrinsic limitations of the human knower? This is the dilemma. One problem in contemporary theology is that many theologians respond to this dilemma by embracing one of the necessary affirmations at the expense of the other. Diller's alternative is to draw upon the work of Karl Barth and Alvin Plantinga to formulate a ‘mutually informed Barth/Plantinga theological epistemology’ which cogently addresses this dilemma without shortchanging either affirmation.
The challenge Diller faces is that, on the matter of theological epistemology, Barth and Plantinga often are presumed to be rivals rather than allies. Yet Diller insists that this presumption is a mirage arising from the distinct nature of their projects rather than foundational theological or philosophical differences. He seeks to unveil the true state of affairs by clarifying each thinker's commitments in light of the other and their respective critics. So, for example, Diller offers a careful examination of Barth's thought on natural theology, apologetics and the relationship between philosophy and theology – all areas of potential friction with Plantinga. He determines precisely what Barth affirmed and rejected on these topics and, in conversation with Barth's critics, explains why Barth did so in light of his unique commitments and goals. He then offers a close reading of Plantinga to see if a plausible interpretation of Plantinga's thought exists which will both correspond to Barth's affirmations and ‘neutralize Barth's main concerns’ (p. 206). The same procedure works, to a lesser degree, in reverse: a critical examination of Plantinga's philosophical arguments becomes the lens through which Barth's theological claims are clarified and directed.
The process of clarifying each thinker's epistemological claims in light of the other enriches them both, with ‘Barth providing what Plantinga lacks in theological depth and Plantinga providing what Barth lacks in philosophical clarity and defense’ (p. 22). The result is an overlapping set of shared fundamental commitments. Barth and Plantinga each adopt a critically realist position undergirded by a ‘theo-foundational’ commitment that Christian knowledge of God is grounded in God and comes solely through God's action. They agree that this knowledge comes by grace and is transformational, corporately known, personal and cognitive. Even though they both believe that this knowledge is received in and through creaturely forms, neither thinks it comes in such a way that it can be reducible to these forms. And they both are convinced that warrant for this knowledge is not dependent upon any general theory even though this knowledge is defensible and coherent with respect to just such a theory.
This ‘unified Barth/Plantinga approach’ forms the basis of the philosophically refined theological epistemology that Diller believes solves theology's dilemma. His proposal presents a challenge, not only to critics of Barth and Plantinga, but also to many of their sympathetic allies. Barth and Plantinga are presumed to be rivals in part because many of their interpreters read them in a way which precludes the claims of the other. In several cases, Diller shows that such readings are simply mistaken, often due to a misunderstanding of the nuances of Barth's and Plantinga's arguments. In other cases, the process of reading Barth and Plantinga in light of one another establishes boundary lines for how their respective claims should be interpreted. One might work out the implications of Plantinga's claims about natural theology and apologetics in a certain way, for instance, precisely in order to avoid falling into the range of Barth's criticism (see pp. 209–10). The benefit of staying within such interpretative limits is the ability to appeal to the coherency and strength of the unified epistemological proposal.
Diller's constructive argument is undergirded by the remarkable clarity of his writing and argumentation. Theological epistemology is inherently complex, and perhaps especially so in the hands of Barth, Plantinga and their critics. All figures involved in the book tend to utilise the same terms and ideas in distinct yet overlapping ways. Such complexity could easily overwhelm, but Diller remains in total command throughout. He describes each figure's claims crisply and with true insight, takes measure of the central issues at stake in their thought, and engages charitably with their critics along the way. His description of Barth's theological epistemology, his rejection of natural theology, his debate with Emil Brunner, his doctrine of the analogia fidei and his approach to scripture could stand on their own as clear and succinct introductions to Barth's thought on these matters. The same could be said for his description of Plantinga's philosophical project and its nuances. In the foreword, Plantinga writes that he has ‘learned a good deal about my own work’ from Diller's volume (p. 11). I suspect that Barth would have said much the same. This volume ranks among the best books on Barth's theology published in the past decade, and it shows the promise of bringing Christian theology and Christian analytic philosophy into conversation around shared fundamental commitments.
