Earlier I referred to 'theory'. Ideology is inside-out theory. In ideological activity, the motivations come from without. With theory, motivations come from within, from our own subjective ideas, experiences, longings and needs. Thus theory can also be called 'self-theory'.
Theory is never static, never rigid.
Our theory, if we fail to constantly evolve and test it against our experience and new information, quickly fossilises into ideological thinking. When we base our activities and ideas on our self-theory, we can clearly see what the actuality behind new information is and choose to take or leave whatever we want. The self-theorist skips and dances through the great supermarket of ideology, tearing open every package, scattering the contents and appropriating what seems good and nourishing and discarding the rest. Ideologists often are brand switchers. The person under the influence of an ideology, a false consciousness, on the other hand, having constructed these barriers, cannot see out.