Faith is confidence or trust in a particular system of religious belief, in which faith may equate to confidence based on some perceived degree of warrant.
The English word faith is thought to date from 1200–50, from the Middle English feith, via Anglo-French fed, Old French feid, feit from Latin fidem, accusative of fidēs (trust), akin to fīdere (to trust).
James W. Fowler (1940-2015) proposes a series of stages of faith-development (or spiritual development) across the human life-span. His stages relate closely to the work of Piaget, Erikson, and Kohlberg regarding aspects of psychological development in children and adults. Fowler defines faith as an activity of trusting, committing, and relating to the world based on a set of assumptions of how one is related to others and the world.
No hard-and-fast rule requires individuals pursuing faith to go through all six stages. There is a high probability for individuals to be content and fixed in a particular stage for a lifetime; stages from 2-5 are such stages. Stage 6 is the summit of faith development. This state is often considered as "not fully" attainable.
There is a wide spectrum of opinion with respect to the epistemological validity of faith.
Fideism is an epistemological theory which maintains that faith is independent of reason, or that reason and faith are hostile to each other and faith is superior at arriving at particular truths (see natural theology). Fideism is not a synonym for religious belief, but describes a particular philosophical proposition in regard to the relationship between faith's appropriate jurisdiction at arriving at truths, contrasted against reason. It states that faith is needed to determine some philosophical and religious truths, and it questions the ability of reason to arrive at all truth. The word and concept had its origin in the mid- to late-19th century by way of Catholic thought, in a movement called Traditionalism. The Roman Catholic Magisterium has, however, repeatedly condemned fideism.