2.(Metaph.) A theory of the origin of ideas which derives them exclusively from sensation. Note: 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.
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.