Making a distinction between affective response and cognitive process resolves semantic contradictions like "realistic" or "neurotic anxiety," "rational anxiety" or "irrational anxiety." It is illogical to qualify an emotion or a feeling state with adjectives ("rational" or "irrational," for example) that are usually applied to ideas or concepts.
One can label a fear as being realistic or unrealistic, rational or irrational. A fear is realistic if based on a sensible assumption, logic and reasoning, and objective observation. It is unrealistic if based on fallacious assumptions and faulty reasoning and is contrary to observation. Anxiety, on the other hand, cannot be labeled realistic or unrealistic because it refers to an affective response not to a process of evaluating reality.
Freud made a distinction between realistic anxiety and neurotic anxiety (1915-17). He regarded realistic anxiety as "something very rational and intelligible" and "a reaction to the perception of external danger"-that is, of an injury which is expected and foreseen. He regarded anxiety as being "connected with the flight reflex" and as "a manifestation of the self preservative instinct" (pp. 393-94). According to Freud, neurotic anxiety results from the perception of internal danger (1926).
He proposed that neurotic anxiety is an affective reaction that occurs when unconscious impulses threaten to become conscious, and results from the fear of the consequences if the defense mechanisms fail and allow the demands of the id to push a person into impulsive instinctual action.