The fear instinct is intimately related to the innermost principle, characteristic of all life, namely the impulse of self-preservation. When, however, the fear instinct becomes deranged by being too intense, and especially when reaching the extreme stage, the instinct becomes pathological, and its functioning leads to degeneration, destruction, and death. Even in its initiatory stages the fear instinct may become abnormal, when associated with objects, situations, and sensori-motor reactions which are otherwise normal and beneficial, or actually requisite in the total economy of life activity of the particular organism. Under such conditions the fear instinct is decidedly pathological.[1] In fact we may say that the fear instinct is the main source of functional, psychopathic diseases. This also holds true of the individual in his aggregate capacity. If the impulse of self-preservation is at the basis of life, the fear instinct is its intimate companion. We may unhesitatingly assert that the fear instinct is one of the most primitive instincts of animal life. We are sometimes apt to overlook the power of fear, because our life is so well guarded by the protective agencies of civilization that we can hardly realize the full extent, depth, and overwhelming effects of the fear instinct. Fear is rooted deep in the nature of animal life, in the impulse of self-preservation. The fear instinct is the earliest instinct to appear in child life. Preyer observed definite manifestations of the fear instinct on the twenty-third day after birth. Perez and Darwin put its appearance somewhat later. In my observations of child life I found the manifestation of the fear instinct during the first couple of weeks, Ribot and other psychologists regard the fear instinct as “the first in chronological order of appearance.” “The progress from brute to man,” says James, “is characterized by nothing so much as the decrease in the frequency of the proper occasion for fear. In civilization in particular it has at last become possible for large numbers of people to pass from the cradle to the grave without ever having had a pang of genuine fear. Many of us need an attack of mental disease to teach us the meaning of the word. Hence the possibility of so much blindly optimistic philosophy and religion. (James refers here to the blind optimism and cheerful metaphysical mysticism handed out to the uncultured classes.) Fear is a genuine instinct, and one of the earliest shown by the human child.”