Propagating a collection of beliefs that provide a theoretical basis for action and behaviour.
Ideology is those aspects of a philosophy which have the most apparently ready application to the world of action, i.e. ethics, politics and economics, and secondarily, psychology, sociology, philosophies of science, history, education, and religion, etc.
Ideology is a secular substitute for religion in which there is emotional adherence to an unsystematic corpus of theories, opinions and beliefs, mainly on how to organize and improve the world.