Once again, propaganda does not base itself on errors, but on exact
facts. It even seems that the more informed public or private opinion is
(notice I say "more," not "better"), the more susceptible it is to
propaganda. The greater a person's knowledge of political and economic
facts, the more sensitive and vulnerable is his judgment. Intellectuals
are most easily reached by propaganda, particularly if it employs
ambiguity. The reader of a number of newspapers expressing diverse
attitudes -- just because he is better informed -- is more subjected
than anyone else to a propaganda that he cannot perceive, even though he
claims to retain free choice in the mastery of all this information.
Actually, he is being conditioned to absorb all the propaganda that
coordinates and explains the facts he believes himself to be mastering.
Thus, information not only provides the basis for propaganda but gives
propaganda the means to operate; for information actually generates the
problems that propaganda exploits and for which it pretends to offer
solutions. In fact, no propaganda can work until the moment when a set
of facts has become a problem in the eyes of those who constitute public
opinion.
-- Jacques Ellul. Propaganda: The formation of men's attitudes
(1965) Chapter 2.