On the basis of the five features above, then, one can recognize as ideologies systems as diverse as Destutt de Tracy’s own science of ideas, the positivism of the French philosopher Auguste Comte, communism and several other types of socialism, fascism, Nazism, and certain kinds of nationalism. That all these “-isms” belong to the 19th or 20th century may suggest that ideologies are no older than the word itself—that they belong essentially to a period in which secular belief increasingly replaced traditional religious faith.