Ideology

n.
  1. The science of ideas.
  2. (Metaph.) A theory of the origin of ideas which derives them exclusively from sensation.
  3. A set or system of theories and beliefs held by an individual or group, especially about sociopolitical goals and methods to attain them; in common usage, ideology is such a set of beliefs so strongly held by their adherents as to cause them to ignore evidence against such beliefs, and thus fall into error -- in this sense it is viewed as a negative trait; contrasted to pragmatism, and distinct from idealism.

By a double blunder in philosophy and Greek, idéologie . . . has in France become the name peculiarly distinctive of that philosophy of mind which exclusively derives our knowledge from sensation. Sir W. Hamilton.