Warranted Christian Belief

The Extended A/C Model is Plantinga's account of how Christian belief can be warranted. It draws on Thomas Aquinas and John Calvin, both of whom held that humans have a natural, noninferential awareness of God—a sensus divinitatis. Because of sin, this capacity is corrupted, so the model adds a second element: the internal instigation of the Holy Spirit, which produces faith in the central truths of the gospel. The model describes a cognitive process designed by God to produce true beliefs about him, functioning properly in a suitable environment . Plantinga's claim is that this model is epistemically possible—consistent with what we know—and that if it is true, Christian belief is warranted.

Warranted Christian Belief is the third volume, following Warrant: The Current Debate (1993), which surveys and rejects contemporary accounts of warrant, and Warrant and Proper Function (1993), which develops Plantinga's own proper functionalist alternative. The first two volumes establish the general epistemology; the third applies it to Christian belief. A reviewer notes that the book is 'more than just a simple application' of the earlier epistemology, because the shift from justification to warrant involves a change in epistemological conviction, not merely a change of topic . Readers who want the full force of Plantinga's argument should read the trilogy in order, though this volume can be read independently by those primarily interested in the religious application.

A de jure objection claims that Christian belief is irrational, unjustified, or intellectually unacceptable, regardless of whether it is true. A de facto objection claims that Christian belief is false. Plantinga's strategy is to argue that all de jure objections fail: if the Extended A/C Model is epistemically possible, then there is a way Christian belief could have warrant, and therefore the claim that it cannot be rational is refuted. As one analysis puts it, 'because the Extended A/C Model is epistemically possible, de jure objections to Christian belief are refuted' . The remaining question is de facto: is Christian belief actually true? Plantinga concedes that philosophy cannot answer this, and that the model's truth is a matter of faith.

Swinburne's central criticism was that Plantinga's externalist account dodges the question the religious sceptic actually asks: are Christian beliefs justified given the believer's evidence and the standards of inductive reasoning we use in science, history, and law? Swinburne argued that only an internalist, evidentialist account can answer this question, and that Plantinga's warrant epistemology 'simply ignores the main problem' . Plantinga replied that the book is aimed in two directions: toward readers generally, to clear away de jure objections, and toward Christian believers, to offer a plausible account of how their belief is in fact warranted . He did not concede that the evidentialist question is the only legitimate one.

The most common misunderstanding is that Plantinga claims to have proven that Christian belief is true, or that he has demonstrated that Christians have warrant. He claims neither. His conclusion is conditional: if the Extended A/C Model is true, then Christian belief is warranted. He explicitly states at the end of the book that whether the model is true is 'the really important question,' and that philosophy cannot answer it—only faith can . A related misunderstanding is that the book is a work of apologetics aiming to convince non-believers. It is a work of epistemology: its target is the philosophical claim that Christian belief cannot be rational, not the claim that it is false.

A substantial portion of the book is devoted to what Plantinga calls 'defeaters' of Christian belief—arguments that, if successful, would undermine its warrant. He examines Freudian and Marxist projection theories, which claim that religious belief is an illusion produced by psychological or social forces; historical-critical biblical scholarship, which raises questions about the reliability of scripture; postmodernist and pluralist objections; and the problem of evil . Plantinga argues that none of these constitutes a successful defeater for the believer who accepts the Extended A/C Model, because the model provides a framework within which the evidence cited by these objections can be reinterpreted. The engagement is extensive and technical, reflecting Plantinga's conviction that de facto objections must be taken seriously even after de jure objections are set aside.