(Latin: fides, faith)
A false system of philosophy, closely related to Traditionalism, which denies the ability of unaided human reason to arrive at certain knowledge of matters meta-physical, religious, and moral; and which insists that an act of faith alone is the means by which to attain certitude.
Its criterion of certitude is authority, which has its foundation in Divine revelation.
The latter is transmitted through the ages by society, in the form of tradition, common sense, or some agent of a social character.
The exponents of this philosophy, among whom were De Bonald, De Lamennais, Bonnetty, Ventura, and Rohrbacher, were theologians and philosophers who wished to offset the prevalent materialistic scepticism and to place Christianity on a firmer basis than human reason can furnish.
The system, which arose in France at the beginning of the 19th century, was extreme, and led to scepticism, subjectionism, agnosticism, pragmatism, and positivism.
It was expressly condemned in two Encyclicals (1832, 1834) of Gregory XVI.
New Catholic Dictionary