The reactions of the fear instinct run the contrary way, approach is precluded from the very start. Fear is not associated with useful objects or events, unless it be in morbid states of fear.
And still fear and disgust may become intimately associated when disgust and its objects awaken the fear instinct, and the fear becomes the fear of disgust or of the disgusting object. Disgust is more of a specialized character, and is associated with particular events or specific objects, while fear, in its primitive form at least, is more of a generalized character.
In the higher forms of life disgust may be so intimately related to fear that the two become synthesized, so to say, and are felt like one emotional state, the state becoming one of fear disgust. In such cases the fear instinct, fear disgust, is a determining factor of the morbid state. This is confirmed by clinical experience of the various cases of psychopathic functional neurosis and psychosis.
In the various morbid states of the depressive types fear is awakened long before any pain is actually suffered, or any particular cause is found by the patient to account for the terror that dominates his mental life. The fear comes first while the representative cause is assigned by the sufferer as the cause of the fear.
Similarly in the functional psychosis and neurosis the object, experience, event, may be quite ordinary without any suggestion of pain or distress in it. In fact, the experience may be indifferent or even pleasant, but when associated with the fear instinct may become the nucleus of a very distressing pathological state. The experience is the occasion, while the fear instinct, the intimate companion of the impulse of self-preservation, is the only cause of functional psychopathic maladies.
The fear instinct in its primitive state is anterior to all experiences of danger, pain, and suffering, as is the case in most of the lower animals. In the higher animals where memory is developed, the fear instinct is associated with some form of representation, however vague, and then fear becomes posterior to experience. In man both forms of fear are present. The anterior form is specially found in children, while in adults the posterior form is, under normal conditions, predominating. The primitive anterior type of the fear instinct is by no means absent, in fact, it is more overpowering, its effects are overwhelming when it comes forth from the subconscious regions to which it is confined, and is manifested under conditions of lowered vitality.
When the strata of dynamic energies are passed and the strata of reserve energies are reached, the reserve energy not being accessible, the fear instinct is elemental, fundamental, while the fear of pain and of some definite representation of danger, or of suffering is a secondary consequence. People may suffer from pain, disease, and even danger, and still have no fear, while others may have never experienced the pain or disease, and still be obsessed by intense pangs of fear. Fear is sui generis, it is at the foundation of animal life.
The fear instinct may be awakened directly by a sensory stimulus, when, for instance, one finds himself in darkness and feels some creeping, slimy thing, or when attacked suddenly with a club or a knife. The fear instinct may again be aroused by an expectation, by something to which his dynamic energies cannot respond adequately, while the reserve energies are in abeyance, such for instance as the expectation of some threatening event either to himself or to the objects bound up with his life existence. When one is threatened with some misfortune, with torture, death, or with a mortal disease, or with a serious operation, or when confronted with great danger against which his energies prove inadequate, in such cases the fear is ideational. These types of fear may in turn be either conscious or subconscious.
We may thus classify the fears as follows: