An ideological theory explains everything: all the past, all the present, and all the future. This means that an ideologue can consider him or herself in possession of the complete truth (something forbidden to the self-consistent fundamentalist). There is no claim more totalitarian and no situation in which the worst excesses of pride are more likely to manifest themselves (and not only pride, but then deceit, once the ideology has failed to explain the world or predict its future).
