In this book, Roberto Di Ceglie offers an historical, theological, and epistemological investigation exploring how commitments to God and/or the good generate the optimum condition to achieve knowledge. Di Ceglie criticizes the common belief that to attain knowledge, one must always be ready to replace one's convictions with beliefs that appear to be proven. He defends a more comprehensive view, historically exemplified by outstanding Christian thinkers, whereby believers are expected to commit themselves to God and to related beliefs no matter how convincing the evidence contradicting such beliefs appears to be. He also argues that both believers and unbelievers can commit themselves to God and the good, respectively, thereby creating a spiritual turn in epistemology that enables them to generate the best possible condition for conducting rational enquiries and discussion.