Faith and Reason

Swinburne argues that faith is not opposed to reason but is a form of rational belief. To have faith is to believe that a particular creed is more probable than its alternatives, based on the total evidence available to the believer . He distinguishes six senses of 'rational belief' and argues that the highest form—rational5—requires that the belief be based on adequate investigation . Faith is thus an evidential matter: the believer should practice the religion whose creed is most probably true, given the evidence. This position rejects fideism, the view that faith is independent of evidence, and it rejects the claim that faith requires belief beyond what the evidence supports.

The second edition (2005) maintains the same structure and conclusions as the original but has been substantially rewritten . Swinburne relates his arguments more closely to classical theologians and philosophers and responds to more recent views. The most significant addition is his explicit engagement with Alvin Plantinga's externalist account of warrant and with John Hick's pluralism, both of which he rejects . The book was originally the concluding volume of a trilogy, following The Coherence of Theism and The Existence of God . While it can be read independently, readers who want the full case for theism should consult the earlier volumes, which Swinburne assumes rather than argues for here.

Swinburne is a committed internalist: he holds that what justifies a belief must be accessible to the believer through introspection and conscious reasoning. Plantinga's externalism holds that a belief has warrant if it is produced by properly functioning faculties aimed at truth, regardless of whether the believer has access to that fact . Swinburne argues that there is 'no intrinsic merit in having a belief justified by externalist criteria of a reliabilist kind' . What we value, he contends, is a belief that results from consciously responding to the evidence in the right way. For Swinburne, if theistic belief is rational, it is primarily a matter of inference from evidence, not of immediate acquaintance or properly basic status.

Swinburne argues that we should practice the religion that has the best goals and is more probably true than the creeds of other religions . He proposes criteria for determining the probabilities of different religious creeds, drawing on the same inductive principles he develops in The Existence of God—such as the principle of simplicity and the principle of testimony . The comparison is not a matter of arbitrary preference but of rational assessment: which creed, given the total evidence, is most likely to be true and to achieve the purposes of religion—worship, salvation, and helping others attain salvation . This comparative approach distinguishes Swinburne from exclusivists who assume the truth of one tradition without examining alternatives.

The book's epilogue is titled 'Faith is Voluntary,' and Swinburne's claim is that while belief itself is not directly under our control—we cannot simply decide to believe something—it is indirectly voluntary through the process of inquiry . We can choose to investigate the evidence, to consider arguments, and to expose ourselves to relevant information. Faith is an act of commitment based on the belief that a creed is probably true, and this commitment is voluntary because it follows from the inquiry we choose to undertake. This position contrasts with views that treat faith as a sheer gift or as an irrational leap; for Swinburne, faith is a rational and responsible act that engages our cognitive agency.

The most common misunderstanding is that Swinburne reduces faith to a cold calculation of probabilities, leaving no room for commitment or trust. He does not. Faith, on his account, requires total commitment to the creed one believes to be most probable . The probability assessment is the rational basis for commitment, not a substitute for it. A related misunderstanding is that Swinburne claims the evidence for theism is so overwhelming that only a fool could disbelieve. He does not: his argument is that the evidence makes theism more probable than its alternatives, not that it compels assent. The book is an exercise in 'strong rationalism,' as William Abraham labeled it, but rationalism does not entail certainty .