SectionS 11-17; vi, xiv-xvi).
In forming their stock of Certainties and Probabilities men employ the faculty of reason, faith in divine revelation, and enthusiasm (chh.
xvii-xix); much misled by the last, as well as by other causes of 'wrong assent' (ch.

xx), when they are at work in 'the three great provinces of the intellectual world' (ch.

xxi), concerned respectively with (1) 'things as knowable' (physica); (2) 'actions as they depend on us in order to happiness' (practica); and (3) methods for interpreting the signs of what is, and of what ought to be, that are presented in our ideas and words (logica)..