Knowledge of God (Great Debates in Philosophy

This monograph presents Alvin Plantinga's mature articulation of reformed epistemology and its implications for rational belief in God. Building on his earlier work in warranted belief and proper function, Plantinga argues that theistic belief can be properly basic—that is, rationally held without evidence or argument. The work systematically defends the thesis that belief in God can possess warrant when produced by cognitive faculties functioning properly in an appropriate epistemic environment.

Plantinga's central innovation lies in his externalist account of warrant, which shifts the focus from internal justification to proper function. He contends that humans possess a sensus divinitatis, a cognitive faculty designed to produce belief in God under appropriate circumstances. When functioning properly, this faculty generates warranted theistic belief directly, without inferential support. This move sidesteps traditional evidentialist demands that religious belief requires propositional evidence or formal argumentation.

The monograph engages critically with the evidentialist objection to theism, particularly as formulated by W.K. Clifford and contemporary philosophers who insist that belief without evidence is intellectually irresponsible. Plantinga argues this requirement is self-defeating and that many of our most fundamental beliefs—in other minds, the external world, and the reliability of memory—are similarly basic. He extends this parity argument to show that theistic belief enjoys the same epistemic status as these commonly accepted beliefs.

Plantinga also addresses the problem of religious diversity and disagreement, arguing that the mere existence of competing religious claims does not undermine the warrant for Christian belief. He develops a model showing how specifically Christian beliefs, including those about sin and salvation, can be warranted through the internal testimony of the Holy Spirit. This extends reformed epistemology beyond generic theism to particular Christian doctrines.

The work's significance lies in its rigorous philosophical defense of the rationality of religious belief without reliance on natural theology or evidential arguments. By developing an alternative epistemological framework, Plantinga challenges the presumption that theistic belief requires independent justification. His approach has influenced subsequent discussions in religious epistemology, spawning debates about the nature of evidence, basicality, and the cognitive science of religion. The monograph represents a sophisticated attempt to show that theistic belief is not merely permissible but can meet the highest standards of epistemic warrant.