Abstract: Can it be justifiable to commit oneself ‘by faith’ to a religious claim when its truth lacks adequate support from one's total available evidence? After critiquing both Wittgensteinian and Reformed epistemologies of religious belief, this book defends a modest fideism that understands theistic commitment as involving ‘doxastic venture’ in the face of evidential ambiguity: practical commitment to propositions held to be true through ‘passional’ causes (causes other than the recognition of evidence of or for their truth). It is argued that the justifiability of religious faith-ventures is ultimately a moral issue — although such ventures can be morally justifiable only if they accord with the proper exercise of our rational epistemic capacities. The book canvasses issues concerning the ethics of belief and doxastic voluntarism. William James's ‘justification of faith’ in The Will to Believe is extended by requiring that justifiable faith-ventures should be morally acceptable both in motivation and content. The book conducts an extended debate between fideists and ‘hard line’ evidentialists, who maintain that religious faith-ventures are never justifiable. It concludes that, although neither fideists nor evidentialists can succeed in establishing their opponents' irrationality, fideism may nevertheless be morally preferable, as a less dogmatic, more self-accepting, even a more loving, position than its evidentialist rival.

Keywords: doxastic voluntarism, epistemology, ethics, evidential ambiguity, evidentialism, fideism, Reformed epistemology, theism, William James