As a socio-cultural phenomenon fundamentalism may be understood as ideological rigidity. Religious worldviews, characteristic of orally transmitted religious traditions, are reshaped as orthodoxies measured by written texts as religious traditions become literate. Ideology is a characteristic of literate religion in so far as literate religion is decontextualized, which means that it requires the justification provided by either the hermeneutics of sacred experts or the new perceptions of converts to overcome the gap between the written and everyday realities. Converts, those new to a religious tradition in its literate form, to overcome high levels of ambiguity use the religious text to establish boundaries between the "nominal" and the "true." Catholicism, which historically combined a great (literate) tradition with a little (nonliterate/folk) tradition, is being restructured by the advent of mass literacy. Biblical fundamentalism among the new readers (converts) in the catholic community is but one form of ideological rigidity, the other being doctrinal fundamentalism. Both threaten the "fullness of Christianity" to which historical catholicism witnesses. Consistent historical criticism of both the biblical and the post-biblical tradition is an antidote to ideological rigidity that encourages the "new readers" to move from text to text towards an ever more open pluralism that will encompass in spirit, if not in material content, the "fullness of Christianity."