The author first rejects interpretations of Aquinas, which he calls “Lockean” because, in the footsteps of Locke, they focus on faith and reason without taking into consideration what seems to be specific to faith, that is, the divine grace because of which the faithful believe. Then, the author concentrates on the theological standpoint from which Aquinas looks at the matter. Finally, he considers the consequences of Aquinas’s view as to the inconclusiveness that often affects debates, especially the religious ones.

The author argues that the firmness of faith championed by outstanding representatives of the Christian tradition is incompatible with the view that one should always prefer beliefs supported by more evidence to beliefs supported by less evidence. The author considers and refutes some perspectives that more or less implicitly minimize this incompatibility. He argues that the Christian faith offers an opportunity to rethink the nature and purpose of debates and to develop a more comprehensive and fruitful epistemological view.

The author shows the limits of the common assumption that beliefs supported by more evidence should always be preferred to beliefs supported by less evidence. This assumption falls into self-referential contradiction; furthermore, it does not explain inconclusiveness, that is, the property of debates – especially the religious ones – whose protagonists are not ready to change their mind, however convincing contrary evidence may appear to them to be.

The author focuses on how Reformed epistemologists and John Henry Newman have criticized Locke’s view of faith and reason, a view that the author, too, rejects. The author’s argument is that their original and intellectually penetrating criticisms are only relatively satisfactory once considered from the viewpoint of what he calls the spiritual turn from mere epistemology.